New H8 Owner

[Peter Clark]

Hi All, 

I'm new to the group, and a new H8 owner.   I've been collecting, restoring and tinkering with computers that I could only dream of having back in the 70's, when I would read about them in Radio Electronics, for about 25 years.   I finally found an H8 I could afford.   I got a little more than I bargained for as a family of mice had made the H8 and it's H17 a home for quite some time.   It also didn't make the trip here in great shape due to not enough packing.   I'm going to be restoring this computer for the next few months (or maybe longer) and was very excited to find this group.  It amazes me the resources that are available for the H8 and H89.   

Here's some pictures of how it arrived.  The H17 was packed on top of the H8 and the weight of it smashed the top of the H8 down, popping off the screws from the left side and crushing it about 1-2".  Luckily nothing was broken, look at the middle picture!

 

I didn't take a picture before I vacuumed out the "mouse house" from the H17, but there was a large collection of insulation and paper filling the whole right size of the H17 unit.   Look at all the rulst from the mouse pee.   I already took out the 3 5.25 drives.   They weren't too bad, but there was a lot of crusted on "stuff" between the bottom of the drive and the cabinet.   Lots of clearning, and lots of Evaporust soaking for the H17.   I can tell the drives are going to need new belts.   

  

H17 case soaking in Evaporust.  

The mice chewed on a few of the wires, and actually chewed through a few of the very fine wires coming from the read head to the circuit board on the 5.25 drives.   This computer is going to keep me busy for a while. 

This H8 as a H8-6 Z80 CPU card, and a DG 64k Ram card.   I've got the H8 cleaned up now and the power supply is working great.  A few of the tantalum capacitors popped when I fired it up the first time, and after replacing those I'm now trying to get just the CPU, front panel and ram card working.   I'm just getting the power and run lights, but I can't get the XCON8 rom to boot.   Still working through diagnostics. 

[dwight]

Make sure to get any mouse urine off any of the IC leads.

This is especially  true for the RAM leads. Most of these are

plated steel.

They will corrode from the insides out. They will be useless that way.

Replace any IC sockets that have had urine in them as well.

Dwight

[Peter Clark]

Thanks a lot for that advice.   I had gone through and tested and reseated all the chips on the CPU and front panel, but I hadn't tackled the ram card yet.   Based on Heathkit's diagnostic flowchart, it would seem there is an issue with the ram, so what you are saying coincides.  I hadn't realized the way the pins would corrode.  That explains the condition of some of the pins.   I had to wire-brush some of the pins of the chips I tested as they were very tarnished and I noticed some of the plating was flaking off.   I wondered what that was - I've never seen that happen before, but then again, I've never had to clean a mouse infested piece of electronics quite this bad.     

Looks like I've got some sockets to replace!

Pete

[Glenn Roberts]

Wow.  Compared to the previous pictures this already looks a lot better!  Great project. Another H8 saved! (or soon to be saved).

 

Welcome to the group, keep us posted and let us know how we can help!

 

-          Glenn

 

 

From: se...@googlegroups.com [mailto:se...@googlegroups.com] On Behalf Of Peter Clark
Sent: Thursday, November 26, 2015 6:45 PM
To: SEBHC <se...@googlegroups.com>
Subject: Re: [sebhc] New H8 Owner

 

Thanks a lot for that advice.   I had gone through and tested and reseated all the chips on the CPU and front panel, but I hadn't tackled the ram card yet.   Based on Heathkit's diagnostic flowchart, it would seem there is an issue with the ram, so what you are saying coincides.  I hadn't realized the way the pins would corrode.  That explains the condition of some of the pins.   I had to wire-brush some of the pins of the chips I tested as they were very tarnished and I noticed some of the plating was flaking off.   I wondered what that was - I've never seen that happen before, but then again, I've never had to clean a mouse infested piece of electronics quite this bad.     

 

Looks like I've got some sockets to replace!

 

 

Pete

 

On Thursday, November 26, 2015 at 3:28:05 PM UTC-6, dke...@hotmail.com wrote:

Make sure to get any mouse urine off any of the IC leads.

This is especially  true for the RAM leads. Most of these are

plated steel.

They will corrode from the insides out. They will be useless that way.

Replace any IC sockets that have had urine in them as well.

Dwight

 

 

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[Peter Clark]

Thanks for the kind words!   The Evaporust really did a lot.   The H17 was in way worse shape than the H8, but the H8 was pretty bad too.   Here's what the H17 base looks like now.   Not great, but at least presentable. 

It took about 3 days of soaking along with frequent wire brushing.   I couldn't get all the rust off, but I got most of it.   I'm thinking of painting the inside of the case with a steel color rustoleum.   Can't decide whether to bother or not. 

I'm really struggling with testing - I'd like to see if I can get the xcon8 monitor working.   I can't get any response from the computer other than the power and run lights lighting up (none of the LED segments light at all).   If I press boot/alter at the same time, run will go off, and then come back on when I release the buttons.   I've tested all the chips on the front panel and on the CPU board (minus the Z80), and I read the rom with my prom programmer and it read correctly.  I have the 444-70 xcon8 rom I think. 

 

   I can't test the ram, but I cleaned all the pins (all 32 chips, man that was tedious) and used some deoxit on them. 

I'm trying to get to as simple a configuration as I can to debug.   Should I be able to boot the monitor without a RAM card installed?   I read that the monitor copies itself to ram, so am wondering if I must have some RAM in the machine to test the CPU/Front Panel. 

Pete

[dwight]

There is a good chance that you have at least one bad RAM.

Since you have a EPROM programmer, I recommend

learning to write some code to check things out.

You'll need to connect something to indicate that you are

completing things. Possibly something on the front panel.

If you have an oscilloscope spend some time checking the bus

signals first.

Start small and work towards more complicated code.

Dwight

[Norberto Collado]

It sounds that you memory board is bad. Also make sure that the memory board is behind the CPU to minimized timing issues. . Can you configure the board to 8K of RAM?

Norberto

On 11/26/15 7:49 PM, "Peter Clark" <pec...@gmail.com> wrote:

Thanks for the kind words!   The Evaporust really did a lot.   The H17 was in way worse shape than the H8, but the H8 was pretty bad too.   Here's what the H17 base looks like now.   Not great, but at least presentable. 

 <https://lh3.googleusercontent.com/-k-Wd1fHd1dI/VlfPv0le4QI/AAAAAAAAB-4/Or8jsxMMKB8/s1600/IMG_9318.jpg>

It took about 3 days of soaking along with frequent wire brushing.   I couldn't get all the rust off, but I got most of it.   I'm thinking of painting the inside of the case with a steel color rustoleum.   Can't decide whether to bother or not. 



I'm really struggling with testing - I'd like to see if I can get the xcon8 monitor working.   I can't get any response from the computer other than the power and run lights lighting up (none of the LED segments light at all).   If I press boot/alter at the same time, run will go off, and then come back on when I release the buttons.   I've tested all the chips on the front panel and on the CPU board (minus the Z80), and I read the rom with my prom programmer and it read correctly.  I have the 444-70 xcon8 rom I think. 

 <https://lh3.googleusercontent.com/-KIVSoCT-AdE/VlfSHxhVItI/AAAAAAAAB_M/KxXgeypg9Wc/s1600/IMG_9300.jpg>

 <https://lh3.googleusercontent.com/-DQfjIdEqFG8/VlfRr8cl-LI/AAAAAAAAB_E/5caLdta6YTY/s1600/IMG_9301.jpg>  

   I can't test the ram, but I cleaned all the pins (all 32 chips, man that was tedious) and used some deoxit on them. 



I'm trying to get to as simple a configuration as I can to debug.   Should I be able to boot the monitor without a RAM card installed?   I read that the monitor copies itself to ram, so am wondering if I must have some RAM in the machine to test the CPU/Front Panel. 



Pete

 

On Thursday, November 26, 2015 at 8:28:34 PM UTC-6, Glenn wrote:

Wow.  Compared to the previous pictures this already looks a lot better!  Great project. Another H8 saved! (or soon to be saved).
 
Welcome to the group, keep us posted and let us know how we can help!
 
-          Glenn

 
 
From: se...@googlegroups.com <javascript:>  [mailto:se...@googlegroups.com <javascript:> ] On Behalf Of Peter Clark
Sent: Thursday, November 26, 2015 6:45 PM
To: SEBHC <se...@googlegroups.com <javascript:> >
Subject: Re: [sebhc] New H8 Owner
 

Thanks a lot for that advice.   I had gone through and tested and reseated all the chips on the CPU and front panel, but I hadn't tackled the ram card yet.   Based on Heathkit's diagnostic flowchart, it would seem there is an issue with the ram, so what you are saying coincides.  I hadn't realized the way the pins would corrode.  That explains the condition of some of the pins.   I had to wire-brush some of the pins of the chips I tested as they were very tarnished and I noticed some of the plating was flaking off.   I wondered what that was - I've never seen that happen before, but then again, I've never had to clean a mouse infested piece of electronics quite this bad.     

 

Looks like I've got some sockets to replace!

 

 <https://lh3.googleusercontent.com/-KzOv385iQ_k/VleYhp3VCOI/AAAAAAAAB-k/oq_rfu0ncCo/s1600/IMG_9333.jpg>

 

Pete

 



On Thursday, November 26, 2015 at 3:28:05 PM UTC-6, dke...@hotmail.com wrote:

[dwight]

It would be best to find someone to try swapping boards with.

My guess is bad RAM but I've seen failed processors and bad bus buffers.

Making small test programs can root out problems that other than

easter egging will find.

Try moving the RAM from bank to bank. To boot, it only needs one bank.

Do note that it could be anything that is failing.

Making small test code for the processor gives you a starting point.

It doesn't need to be fancy, just to blink a light is a good starting point.

If that won't run, you can at least narrow it down to the processor board.

On one machine that I had particular problems getting up and running,

I had a bunch of switches to replace the processor with. I could manually

check everything except DRAM.

Sometimes you need to be creative.

Dwight

---

From: se...@googlegroups.com <se...@googlegroups.com> on behalf of Norberto Collado <norberto...@koyado.com>
Sent: Thursday, November 26, 2015 10:49 PM
To: se...@googlegroups.com

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[Peter Clark]

Looks like I might have spoken too soon as I was going back through testing on the front panel and I found that U119, a CD4028 BCD-Decimal chip, is bad, at least according to my cheap tester.  I can't find any in my stock or in anything else I have so I ordered one to swap and see if that changes anything. 

I think the 4028 chip problem may explain why I'm not getting any LED segments to light, but I haven't looked at the schematic enough yet to see if it could also be the reason I'm not getting the MON and ION lights to come on. 

I don't have a manual for the DG ram card, but it does look like I can turn off/on each bank, so where I cannot get to just 8k, I can get to 16K.   I've tried that, along with swapping the 4116 chips between banks, but that yielded no changes in behavior.   I found someone selling a Heathkit H8-16 16k ram card on ebay so I bought that in the hopes I could have an alternative ram card to test with.   I also ordered some new 4116 ram chips to have for testing. 

I'm curious what you guys think of the settings on this ram card.   I've circled two areas on the photo below.   On the left is the "MEM ADDR", which I'm assuming is where to start the memory on the card in the address space.   Below that is what I am thinking is the bank enable/disable.   I have tried disabling all but bank 0.    On the right is the "PORT ADDR" which is jumpered to 7 7 0.    Also, right next to the card edge connector is a "ROM DIS" jumper.   One position of this jumper is NC, the other connects to one of the bus pins, and it's jumpered to the bus pin side.    

Is port 7 7 0 typical for this type of ram card?  What function do you think ROM DIS would have on a ram card?

[dwight]

The port would be for extended memory banks, beyond 64K.

I believe there should be a way to disable that part and use it as

a main memory board, so  7 7 0 may not mean anything.

Dwight

---

From: se...@googlegroups.com <se...@googlegroups.com> on behalf of Peter Clark <pec...@gmail.com>
Sent: Saturday, November 28, 2015 7:05 AM
To: SEBHC

Subject: Re: [sebhc] New H8 Owner

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[Peter Clark]

Makes me wonder if there were additional memory boards in this computer before it was sold.   If this card was configured for memory above 64k, wouldn't that imply there was another card in here for the first 64k at some point?   I'll look through the jumpers to see if I can figure out how to set it for the first 64k. 

[Norberto Collado]

Hello Peter,

If you feel that you are not getting anywhere, please feel free to send me the CPU and the memory board, so that I can test them in my Super H8 ( http://koyado.com/Heathkit/H8_Ultimate_Computer.html), known working computer. I can update the CPU EPROM to PAM37 while keeping the XCON-8 as well. This will enable your system to be able to boot from our hard drive solution and the H8-Z37 solutions.

My address is:

Norberto Collado
P.O. Box #268
Dupont, WA 98327-0268

Best Regards,
Norberto :)

On 11/28/15 7:05 AM, "Peter Clark" <pec...@gmail.com> wrote:

Looks like I might have spoken too soon as I was going back through testing on the front panel and I found that U119, a CD4028 BCD-Decimal chip, is bad, at least according to my cheap tester.  I can't find any in my stock or in anything else I have so I ordered one to swap and see if that changes anything. 

 <https://lh3.googleusercontent.com/-E4U5t2MAQ8E/Vlm90jDaFrI/AAAAAAAAB_k/v79eODqxqsg/s1600/IMG_9331.jpg>

I think the 4028 chip problem may explain why I'm not getting any LED segments to light, but I haven't looked at the schematic enough yet to see if it could also be the reason I'm not getting the MON and ION lights to come on. 

I don't have a manual for the DG ram card, but it does look like I can turn off/on each bank, so where I cannot get to just 8k, I can get to 16K.   I've tried that, along with swapping the 4116 chips between banks, but that yielded no changes in behavior.   I found someone selling a Heathkit H8-16 16k ram card on ebay so I bought that in the hopes I could have an alternative ram card to test with.   I also ordered some new 4116 ram chips to have for testing. 

I'm curious what you guys think of the settings on this ram card.   I've circled two areas on the photo below.   On the left is the "MEM ADDR", which I'm assuming is where to start the memory on the card in the address space.   Below that is what I am thinking is the bank enable/disable.   I have tried disabling all but bank 0.    On the right is the "PORT ADDR" which is jumpered to 7 7 0.    Also, right next to the card edge connector is a "ROM DIS" jumper.   One position of this jumper is NC, the other connects to one of the bus pins, and it's jumpered to the bus pin side.    

 <https://lh3.googleusercontent.com/-mydrDlidMjE/VlnByxeJ1mI/AAAAAAAAB_0/To21p-_Rros/s1600/IMG_9333.jpg>

[Peter Clark]

Thank you so much for that offer Norberto!   That would be awesome. I really appreciate it. :)   I was reading a bit about the Z67-IDE+ you developed and I would love to build one of these.   It sounds like a great way to both have a reliable storage solution along with a great way to get new software to the H8 easily using the CF card. 

I figure I'll wait until the new CD2048 comes and see if that fixes the front panel, and I'll send the boards after that.   Probably a week or so, if that works for you.   

Thanks again for the very kind offer!

[Norberto Collado]

Not a problem! What other controllers do you have for your H8? The Z67-IDE+ requires the WH8-37 board.

Norberto

[Peter Clark]

I have the HA8-6 Z80 CPU card, the DG 64D 64k ram card, the H17 controller card, and the H8-4 Multi-port serial card.   

[Norberto Collado]

Thanks! I will check to see if I do have an spare H8-Z67 controller.

Norberto

-------- Original Message --------
Subject: Re: [sebhc] New H8 Owner

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[Peter Clark]

I am not having much luck with the diagnostics.   I got the 4028 chip and replaced it, but no change.   Then I received the H8-8 16k ram card and 8080 cpu card and swapped them in, but still no change.   I tested the bus just to be sure there were no issues with that.   Either I have some very hard to find issue with the front panel, or a very unfortunate set of coincidences with RAM/CPU cards.   My gut tells me there is some issue with the front panel, I think I'm going to have to dig much deeper and go through it very thoroughly.   

[Norberto Collado]

With the 8080A CPU board you will need the HA8-8 Extended Configuration board depending on PROM FW.

Take a break and send me only the two memory boards along with the Z80 CPU. No need to send the 8080A CPU board. Once I get the Z80 working along with your memory board, then the only thing that you will need to debug is the H8 front panel if needed. If you have spares RAM IC's, send those as well in case I need to replace a RAM IC. 

Thanks,

Norberto 

-------- Original Message --------
Subject: Re: [sebhc] New H8 Owner
From: Peter Clark <pec...@gmail.com>

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[Peter Clark]

The 8080A board I have has a piece of scotch tape on it with "PAM8 ROM" written in pencil on it.   The H8-16 card was labelled " modified for Z80", but I undid that modification before I tested.   It's more than likely I missed something though as I'm not familiar with this board and cannot find any manuals for it.   

I'll throw in the towel and take you up on your very kind and generous offer to have a look at these.   I've got some 4116 chips coming and should be here this week, I'll package those with the boards and send them your way.   Thank you again for the help!

I'm planning to go through the front panel while the boards are on there way to you.   Any tips  for a novice on common issues with the front panel?

Pete

[Peter Clark]

Hi Norberto, 

The cards are on their way.   Should be there in a few days.   Thanks again for the help!

Pete

On Saturday, November 28, 2015 at 2:25:23 PM UTC-6, Norby wrote:

[Norberto Collado]

Cool! On your H8 front panel debug question, the circuit is very simple to debug once your CPU and RAM cards are operating. Do you have an scope to make debugging easier?

Norberto

-------- Original Message --------
Subject: Re: [sebhc] New H8 Owner
From: Peter Clark <pec...@gmail.com>

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[Peter Clark]

Yeah, I do.   I noticed there were some examples of expected waveforms on the schematic.  

Hopefully it's ok, and will work fine once I have a functioning cpu/ram... 

Pete

[Norberto Collado]

Hello Pete,

I went this afternoon to the post office and found the DG box (very cool!) with the cards. I will spend time this weekend in debugging them to get your H8 up and running as soon as possible.

Thanks,
Norberto

[Peter Clark]

Hey Norborto, 

I was really excited to receive that DG box with the original H8 8080 cpu card, and the 16k ram card that I bought on ebay.  How fitting eh?    Kind of a nice addition to the collection.   It just seemed like sending you the cards in an original 1970's box was the right thing to do! 

Thanks again for your help, I am so excited to get this wonderful computer up and running again.   If the hard sector emulator works for the H8, I may even be able to create some disks with HDOS and CPM for it!

The H17 disk drive unit is coming along.   I have 2 of the 3 floppy drives repaired, and still working on the 3rd.   I should have it back together in the next week or so.   The mice chewed through the floppy ribbon cable, so I have to make a new one, but that should be no big deal. 

Let me know when you are ready and I'll email you a pre-paid shipping label for return shipping.   

Pete

[Glenn Roberts]

Peter: just a suggestion: Have you considered using 5-1/4” hard sectored disks directly on the drives?  I think these are still available (for a price!) from Athana, or some of us have hole punches to take DS/DD 360K “PC” disks and punch the 10 extra sector holes in them for use with the H17 drives.  Granted some of the older media may be unreliable but I’ve had good luck with the Athana brand or ones I’ve punched.  It’s an option for you to consider and would avoid the need for the hard sector emulator (why emulate when you’ve got the real thing?!).  You might want to at least give it a try and see how reliable they are.

 

You can generate a hard sectored copy of any disk in Les’ archive using his H8D utility and a serial link to a PC…

 

-          Glenn

 

 

From: se...@googlegroups.com [mailto:se...@googlegroups.com] On Behalf Of Peter Clark
Sent: Thursday, December 10, 2015 8:30 PM
To: SEBHC <se...@googlegroups.com>
Subject: Re: [sebhc] New H8 Owner

 

Hey Norborto, 

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[Norberto Collado]

Hello Pete,

I really enjoyed looking at the box for a while before opening it and thank you for such moment; priceless!

I took a quick look at the CPU this evening and one jumper is cut off. Rather than trying in getting the CPU running as it is, I will proceed to update it with PAM37 and apply the reworks. The Heath 16KB memory board has the mod to bypass the write delayed cycle to allow the Z80 CPU to run at 4MHz with such memory. I’m going to put it back the way it was originally designed and will replace the IC with a fast device to be able to run a 4MHz with the delayed write cycle circuit. I do not think such RAM can run at 4MHZ without the delayed cycle circuitry.

The DG board looks super cool. The target is to get the Z80 CPU and the Heath 16K RAM operational so that you can check the front panel. I will leave the DG RAM board for last and if I cannot get it to work (lack of schematics) I will return it back to you. For me it is easier to order a PCB that can support 64KB of RAM rather than spending a lot of time in getting the old DG board to work.

For my second H8, I’m looking into possibly ordering some of the 256KB RAM board that I designed back in the Mid 80’s by using the newest RAM’s.

I think I might have some 5.25” hard sector floppy media and if I do, I will send you one with HDOS, so that you can test your H17 floppy drives.

There is a rework for the H17 board that needs to be in place once I make the changes to the Z80 CPU board. Please send a picture of your H17 board for side 1 and side 2, so that we can evaluate if you are missing such rework.

For your H8, what you want at the end is the H17 along with the H67 board to have a working solution. Let me check to see what I might have to eventually support such configuration.

Best Regards,
Norby

[Peter Clark]

Hi Glenn, 

I like the idea!  I'm interested in finding some hard sectored disks, or making them.    I do have a number of DS/DD disks I could start with.   I read about someone who had made a device to punch the holes, but I couldn't find anyone selling them.   I'm not sure I'd be able to make one.   

I did drop an email to Athana to inquire if they had any hard sectored disks, but never got a reply.   I'll give it another shot. 

I can't wait to get this baby up and running so I can try out the serial transfer.   You have to key in a short program on the front panel that receives the transfer and writes it to disk right?  I've read about this on Les's site I believe. 

Pete

[Norberto Collado]

From Joe:

Athana Model 47-7510 double sided/double density 10 sector 40 tracks

http://www.athana.com/html/diskette.html

Ask for a quote on Athana Model 47-7510

They are expensive; but, this may be about the only source for new floppies
like this.

Joe

Thanks,
Norberto

On 12/11/15 6:51 PM, "Peter Clark" <pec...@gmail.com> wrote:

Hi Glenn, 

I like the idea!  I'm interested in finding some hard sectored disks, or making them.    I do have a number of DS/DD disks I could start with.   I read about someone who had made a device to punch the holes, but I couldn't find anyone selling them.   I'm not sure I'd be able to make one.   

I did drop an email to Athana to inquire if they had any hard sectored disks, but never got a reply.   I'll give it another shot. 

I can't wait to get this baby up and running so I can try out the serial transfer.   You have to key in a short program on the front panel that receives the transfer and writes it to disk right?  I've read about this on Les's site I believe. 

Pete




On Thursday, December 10, 2015 at 8:49:35 PM UTC-6, Glenn wrote:

Peter: just a suggestion: Have you considered using 5-1/4” hard sectored disks directly on the drives?  I think these are still available (for a price!) from Athana <http://www.athana.com/> , or some of us have hole punches to take DS/DD 360K “PC” disks and punch the 10 extra sector holes in them for use with the H17 drives.  Granted some of the older media may be unreliable but I’ve had good luck with the Athana brand or ones I’ve punched.  It’s an option for you to consider and would avoid the need for the hard sector emulator (why emulate when you’ve got the real thing?!).  You might want to at least give it a try and see how reliable they are.
 
You can generate a hard sectored copy of any disk in Les’ archive <http://sebhc.lesbird.com/software.html>  using his H8D utility <http://sebhc.lesbird.com/software/Utilities/H8DUtilityV1_51.zip>  and a serial link to a PC…
 
-          Glenn

[Peter Clark]

Hi Norberto, 

That is awesome, I really appreciate it.   Thanks so much for updating the CPU with the new rom and rework that it needs.   

I think my H17 board has the modifications from what I saw in the manual for the CPU.   Here's some  pictures so that you can double check.   

 

Having an HDOS disk to boot and test with would be really great!   

From what I've read, the H67 would give me the ability to have an IDE interface that I could use a CF card with.   Is that right?   That would be really great.   I read about the H67 emulator on your site.   It's amazing how fast that boots!

Look what the mice did to my floppy cable... 

Pete

On Thursday, December 10, 2015 at 11:26:44 PM UTC-6, Norby wrote:

Hello Pete,

[Glenn Roberts]

That’s an amazingly clean looking card for one that came from what appeared to be a real junker system!

 

From: se...@googlegroups.com [mailto:se...@googlegroups.com] On Behalf Of Peter Clark
Sent: Friday, December 11, 2015 10:19 PM
To: SEBHC <se...@googlegroups.com>
Subject: Re: [sebhc] New H8 Owner

 

Hi Norberto, 

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[Glenn Roberts]

There were a limited number of those punches made.  I’ve got one but I’m finding it has trouble punching certain holes (hole #7 is particularly problematic on mine).  I may have to figure out how to “sharpen” mine!

 

I’ve had mixed results using old media; depends on the brand.  Have had pretty good results using DS/DD media that were punched.  I’ve had good luck with the Athana disks.

 

Yes the serial transfer was invented by Dwight Elvy.  It’s simple but very elegant.  It’s also built into Les’ H8D utility.  With it you can bootstrap a system even with no working (bootable) disks.

 

From: se...@googlegroups.com [mailto:se...@googlegroups.com] On Behalf Of Peter Clark
Sent: Friday, December 11, 2015 9:51 PM
To: SEBHC <se...@googlegroups.com>
Subject: Re: [sebhc] New H8 Owner

 

Hi Glenn, 

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[Norberto Collado]

Your H17 board is missing the side select cable. See attached picture and add the modification.

Norberto

On 12/11/15 7:19 PM, "Peter Clark" <pec...@gmail.com> wrote:

Hi Norberto, 

That is awesome, I really appreciate it.   Thanks so much for updating the CPU with the new rom and rework that it needs.   

I think my H17 board has the modifications from what I saw in the manual for the CPU.   Here's some  pictures so that you can double check.   

<https://lh3.googleusercontent.com/-TRX_FeujF5M/VmuRCegnJ6I/AAAAAAAACAo/8y6SwVAMAAo/s1600/IMG_9442.jpg>  <https://lh3.googleusercontent.com/-Y1CmSbFumV0/VmuRHyz80GI/AAAAAAAACAw/0UoESdsSjW8/s1600/IMG_9443.jpg>  

 <https://lh3.googleusercontent.com/-NUY2QBiewQ0/VmuRWVOPrZI/AAAAAAAACA4/5oQ9w7XUefs/s1600/IMG_9444.jpg>

Having an HDOS disk to boot and test with would be really great!   

From what I've read, the H67 would give me the ability to have an IDE interface that I could use a CF card with.   Is that right?   That would be really great.   I read about the H67 emulator on your site.   It's amazing how fast that boots!

Look what the mice did to my floppy cable... 

 <https://lh3.googleusercontent.com/-bRiAJHJWbhE/VmuR6m6XE5I/AAAAAAAACBA/xUcWz3f3sn0/s1600/IMG_9445.jpg>

Pete


On Thursday, December 10, 2015 at 11:26:44 PM UTC-6, Norby wrote:

[Norberto Collado]

Also I can fix your H17 cable.

:) Norberto

[Steven Hirsch]

On 12/11/2015 11:54 PM, Glenn Roberts wrote:

> There were a limited number of those punches made. I’ve got one but I’m
> finding it has trouble punching certain holes (hole #7 is particularly
> problematic on mine). I may have to figure out how to “sharpen” mine!

I have one of Dwight's punches and am experiencing the same type of issue.
Certain holes "tear" the disk rather than making a clean punch. I did notice
a raised burr around most of the holes on the die. Taking a flat-file to it
helped considerably, but there are still two that cause problems with some media.

As a "Hail Mary" play, it may be possible to strike the die in the vicinity of
the hole and deform it to reduce the diameter at the very top. That will
either fix or ruin it - YMMV, past performance is no guarantee of future
returns, Do Not try this at home, etc, etc.

I can routinely get 7-8 working diskettes out of 10 tries, so not too bad and
definitely better than Athana's usurious prices.

It is typical for hand-punched diskettes to be noisier in operation due to
slight crowning of the holes dragging on the sleeve liner. But, again, this
depends on the thickness of the media, luck, phases of the moon, etc.

It would be helpful if someone with a good micrometer could determine the
thickness of various brands of diskettes. In this case, the thicker the
better to reduce tearing.

[dsem...@verizon.net]

For what it's worth on the hole punch, I don't have a Dwight Punch, but I sometimes got the same ragged punch when marking the hole positions and then punching each with a standard office hole punch (with the proper sized die).  In my case I suspect I twisted the relative positions of the media and the punch while squeezing the punch handle.  Of course, this shouldn't happen with the "punch 'em all at once" tool.

Again, just FWIW.

Dan

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[Glenn Roberts]

I may try the filing trick. Also thought about your hail mary solution. I considered whether the die itself could be flipped over (it's attached to the plastic mount with two screws) but it appears to not be 100% symmetrical about the screw axis. For now I've been able to get by...

-----Original Message-----
From: se...@googlegroups.com [mailto:se...@googlegroups.com] On Behalf Of Steven Hirsch
Sent: Saturday, December 12, 2015 10:13 AM
To: se...@googlegroups.com
Subject: Re: [sebhc] New H8 Owner

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[Norberto Collado]

Hello Pete,

The Heath 16K RAM is completely dead. The DG board is unstable on power-on and it does not see the complete 64K of RAM (picture attached). I'm going to focus on the 16K RAM first to get it working.

Thanks,

Norberto 

-------- Original Message --------
Subject: Re: [sebhc] New H8 Owner

From: Norberto Collado <norberto...@koyado.com>
Date: Thu, December 10, 2015 9:26 pm
To: "se...@googlegroups.com" <se...@googlegroups.com>

Hello Pete,

I really enjoyed looking at the box for a while before opening it and thank you for such moment; priceless!

I took a quick look at the CPU this evening and one jumper is cut off. Rather than trying in getting the CPU running as it is, I will proceed to update it with PAM37 and apply the reworks. The Heath 16KB memory board has the mod to bypass the write delayed cycle to allow the Z80 CPU to run at 4MHz with such memory. I’m going to put it back the way it was originally designed and will replace the IC with a fast device to be able to run a 4MHz with the delayed write cycle circuit. I do not think such RAM can run at 4MHZ without the delayed cycle circuitry.

The DG board looks super cool. The target is to get the Z80 CPU and the Heath 16K RAM operational so that you can check the front panel. I will leave the DG RAM board for last and if I cannot get it to work (lack of schematics) I will return it back to you. For me it is easier to order a PCB that can support 64KB of RAM rather than spending a lot of time in getting the old DG board to work.

For my second H8, I’m looking into possibly ordering some of the 256KB RAM board that I designed back in the Mid 80’s by using the newest RAM’s.

I think I might have some 5.25” hard sector floppy media and if I do, I will send you one with HDOS, so that you can test your H17 floppy drives.

There is a rework for the H17 board that needs to be in place once I make the changes to the Z80 CPU board. Please send a picture of your H17 board for side 1 and side 2, so that we can evaluate if you are missing such rework.

For your H8, what you want at the end is the H17 along with the H67 board to have a working solution. Let me check to see what I might have to eventually support such configuration.

Best Regards,
Norby

On 12/10/15 5:30 PM, "Peter Clark" <pec...@gmail.com> wrote:

Hey Norborto, 

I was really excited to receive that DG box with the original H8 8080 cpu card, and the 16k ram card that I bought on ebay.  How fitting eh?    Kind of a nice addition to the collection.   It just seemed like sending you the cards in an original 1970's box was the right thing to do! 

Thanks again for your help, I am so excited to get this wonderful computer up and running again.   If the hard sector emulator works for the H8, I may even be able to create some disks with HDOS and CPM for it!

The H17 disk drive unit is coming along.   I have 2 of the 3 floppy drives repaired, and still working on the 3rd.   I should have it back together in the next week or so.   The mice chewed through the floppy ribbon cable, so I have to make a new one, but that should be no big deal. 

Let me know when you are ready and I'll email you a pre-paid shipping label for return shipping.   

Pete

On Wednesday, December 9, 2015 at 9:38:51 PM UTC-6, Norby wrote:

Hello Pete,

I went this afternoon to the post office and found the DG box (very cool!) with the cards. I will spend time this weekend in debugging them to get your H8 up and running as soon as possible.

Thanks,
Norberto

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[Lee Hart]

dsem...@verizon.net wrote:
> For what it's worth on the hole punch, I don't have a Dwight Punch, but
> I sometimes got the same ragged punch when marking the hole positions
> and then punching each with a standard office hole punch (with the

> proper sized die)...

Another idea, for what it's worth... In the 1970's I worked for Kodak in
Rochester NY. They punched the sprocket holes in miles of mylar 35mm
film every day. As I recall, the film was cooled, to make it more
brittle to get sharper punches. Or maybe the cooling was just to keep
the punches from heating up; after all, they were punching millions of
holes an hour.

Anyway, it might be worth putting the disk in a freezer, and punching it
cold.

--
The prime instinct of children at play is to build and to create.
They will make things of whatever materials are at hand, and use the
whole force of dream and fancy to create something out of nothing.
-- Alfred P. Morgan
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com

[Norberto Collado]

I'm trying to fix Pete's Heath 16K RAM board and there is an IC labeled 443-46. Can someone decode this to a 74LSXX equivalent part?

Thanks,

Norberto

[dsem...@verizon.net]

Norberto,

http://www.qsl.net/w6ovp/heathkitparts.htm says it's a 7402N.  Does it look like one? - Dan

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[Norberto Collado]

Dan,

Thanks for the information. It is hard to tell if same part as I do not have the schematics. I’m making a copy of the link into my website; great decoder information.

Norberto

On 12/12/15 12:11 PM, "dsem...@verizon.net" <dsem...@verizon.net> wrote:

[Steven Hirsch]

On 12/12/2015 01:31 PM, Lee Hart wrote:
> dsem...@verizon.net wrote:
>> For what it's worth on the hole punch, I don't have a Dwight Punch, but
>> I sometimes got the same ragged punch when marking the hole positions
>> and then punching each with a standard office hole punch (with the
>> proper sized die)...
>
> Another idea, for what it's worth... In the 1970's I worked for Kodak in
> Rochester NY. They punched the sprocket holes in miles of mylar 35mm film
> every day. As I recall, the film was cooled, to make it more brittle to get
> sharper punches. Or maybe the cooling was just to keep the punches from
> heating up; after all, they were punching millions of holes an hour.

That is an excellent suggestion! I will give it a try. The only possible
"gotcha" is that the diskette requires a lot of handling to get the fixture
setup properly, so it may be necessary to chill the entire thing. Now that I
think about it, freezing the die and heating the punch slightly may also solve
the problem. Condensation could be a show-stopper, but winter in Vermont is
not all that humid.

A few things to try anyway.

[Glenn Roberts]

That’s a 7402

--

[Norberto Collado]

Glenn,

Do you have a picture of your Heath 16K RAM board? The chips that controls the timing are different and I have a 2MHz signal on the 74LS240 bus data driver at the enabled signal. The board was modified and the IC's were change. The 74LS240 data drivers are overheating because of the continuous 2MHz signals which is enabling the read/write cycles at the same time per my scope. 

If you have a picture that will be great. The IC's in question are:

U142, U143, U144, and U140.

Thanks,

Norberto

-------- Original Message --------
Subject: RE: [sebhc] New H8 Owner

From: "Glenn Roberts" <glenn.f...@gmail.com>
Date: Sat, December 12, 2015 1:13 pm
To: <se...@googlegroups.com>

That’s a 7402

[Max Scane]

I don't know if this helps but I have a WH8-16 and the ICs in question are:

U142 - 443-875 - 74LS32

U143 - 443-730 - 74LS74

U144 - 443-872 - 74LS14

U140 - 443-855 - 74LS283

Cheers!

Max

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[Norberto Collado]

I found the schematics, so I'm good now!

[Lee Hart]

Max Scane wrote:
> I don't know if this helps but I have a WH8-16 and the ICs in question are:
>
> U142 - 443-875 - 74LS32
> U143 - 443-730 - 74LS74
> U144 - 443-872 - 74LS14
> U140 - 443-855 - 74LS283

Norberto, I also have a spare 16k card you can borrow for
inspection/test to get his working. My card was working with the stock
8080 CPU when I pulled it to upgrade memory.

[Norberto Collado]

Hello Max,

I will try that. I have the H8-16 card which is different from the WH8-16. I have a delta on the following based on your feedback:

H8-16

U142 = 7402

U143 = 74LS74

I have the WH8-16 schematics and they have the following:

U142 = 74LS74

U143 = 7402

I will try the 74LS32 and I hope that will fix the issue.

Norberto

-------- Original Message --------
Subject: Re: [sebhc] New H8 Owner
From: Max Scane <mjs...@gmail.com>
Date: Sat, December 12, 2015 3:26 pm
To: se...@googlegroups.com

I don't know if this helps but I have a WH8-16 and the ICs in question are:

U142 - 443-875 - 74LS32

U143 - 443-730 - 74LS74

U144 - 443-872 - 74LS14

U140 - 443-855 - 74LS283

Cheers!

Max

On Sun, Dec 13, 2015 at 10:19 AM, Norberto Collado <norberto...@koyado.com> wrote:

Glenn,

Do you have a picture of your Heath 16K RAM board? The chips that controls the timing are different and I have a 2MHz signal on the 74LS240 bus data driver at the enabled signal. The board was modified and the IC's were change. The 74LS240 data drivers are overheating because of the continuous 2MHz signals which is enabling the read/write cycles at the same time per my scope. 

If you have a picture that will be great. The IC's in question are:

U142, U143, U144, and U140.

Thanks,

Norberto

-------- Original Message --------
Subject: RE: [sebhc] New H8 Owner
From: "Glenn Roberts" <glenn.f...@gmail.com>
Date: Sat, December 12, 2015 1:13 pm
To: <se...@googlegroups.com>

That’s a 7402

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[Norberto Collado]

Lee,

Attached is a picture of the board that I have. U148 and U147 overheating like crazy. If your board matches this one, please let me know the IC's for U142 and U143.

Thanks,

Norberto

-------- Original Message --------
Subject: Re: [sebhc] New H8 Owner

From: Lee Hart <leea...@earthlink.net>
Date: Sat, December 12, 2015 3:40 pm
To: se...@googlegroups.com

Max Scane wrote:
> I don't know if this helps but I have a WH8-16 and the ICs in question are:
>
> U142 - 443-875 - 74LS32
> U143 - 443-730 - 74LS74
> U144 - 443-872 - 74LS14
> U140 - 443-855 - 74LS283

Norberto, I also have a spare 16k card you can borrow for
inspection/test to get his working. My card was working with the stock
8080 CPU when I pulled it to upgrade memory.

--
The prime instinct of children at play is to build and to create.
They will make things of whatever materials are at hand, and use the
whole force of dream and fancy to create something out of nothing.
-- Alfred P. Morgan
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com

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[Norberto Collado]

Hello Max,

U143 with a 74LS32 fixed the issue. The H8-16 board is now up and running, and very stable. See attached picture.

So for the H8-16 16K board the IC's values are:

U143 = 74LS32

U142 = 74LS74.

Max thanks a lot! Next stop is to test the Heath CPU. I hope it works on first try.

Norberto :)

-------- Original Message --------
Subject: RE: [sebhc] New H8 Owner
From: "Norberto Collado" <norberto...@koyado.com>
Date: Sat, December 12, 2015 3:58 pm
To: se...@googlegroups.com

Hello Max,

I will try that. I have the H8-16 card which is different from the WH8-16. I have a delta on the following based on your feedback:

H8-16

U142 = 7402

U143 = 74LS74

I have the WH8-16 schematics and they have the following:

U142 = 74LS74

U143 = 7402

I will try the 74LS32 and I hope that will fix the issue.

Norberto

-------- Original Message --------
Subject: Re: [sebhc] New H8 Owner
From: Max Scane <mjs...@gmail.com>
Date: Sat, December 12, 2015 3:26 pm
To: se...@googlegroups.com

I don't know if this helps but I have a WH8-16 and the ICs in question are:

U142 - 443-875 - 74LS32

U143 - 443-730 - 74LS74

U144 - 443-872 - 74LS14

U140 - 443-855 - 74LS283

Cheers!

Max

On Sun, Dec 13, 2015 at 10:19 AM, Norberto Collado <norberto...@koyado.com> wrote:

Glenn,

Do you have a picture of your Heath 16K RAM board? The chips that controls the timing are different and I have a 2MHz signal on the 74LS240 bus data driver at the enabled signal. The board was modified and the IC's were change. The 74LS240 data drivers are overheating because of the continuous 2MHz signals which is enabling the read/write cycles at the same time per my scope. 

If you have a picture that will be great. The IC's in question are:

U142, U143, U144, and U140.

Thanks,

Norberto

-------- Original Message --------
Subject: RE: [sebhc] New H8 Owner
From: "Glenn Roberts" <glenn.f...@gmail.com>
Date: Sat, December 12, 2015 1:13 pm
To: <se...@googlegroups.com>

That’s a 7402

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[Lee Hart]

Norberto Collado wrote:
> Lee,
>
> Attached is a picture of the board that I have. U148 and U147
> overheating like crazy. If your board matches this one, please let me
> know the IC's for U142 and U143.

Norberto,

My board is a little different. Same model# Heath "H8-16 16k STATIC
RAM", board part #85-2197 (yours is 85-2097-1, date code 090878 (yours
is 030778). U142 is 74LS74A, U143 is 7402. Photo attached.

[Max Scane]

Mine has a lot less resistors (only on the address switch).  Part number 85-2097-1 date code 030778

Cheers!

Max

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[Norberto Collado]

Lee,

This is a better design board and my schematics matches this one. On the
board that I have they applied the same IC's that are on your board and that
caused the data bus drivers to overheat. I replaced all of the 74LS240 with
the F version. Also replaced the 74LS74 and the 74LS14 with the F version as
well. Board and I are very happy now! :)

Thanks to Max feedback, I was able to get the board operational with the
correct IC.

I'm updating the CPU with the reworks and hopefully it will work.

Thanks for the feedback.

Norberto

[Glenn Roberts]

I've got at least three of the Heath 16K boards. Mine are the 2197's, purchased new (by me) in 1980 or so. These were in my original H8 system - still are. That system I've left in original condition (8080 CPU, H17 and H-8-4 serial card). Later I purchased a used 8k card to bring my system up to 56K (which was the max without the zero org option). Since I bought them new I've still got all the original doc's.

In the 1978 catalog these were $395/board. According to the Bureau of Labor Statistics CPI Inflation Calculator, $395 in 1978 dollars has the same buying power as $1,440.89 today!! But I bought my boards around 1980/81. By then I think they were $299 ($782.33 today) and in the spring/summer 1982 catalog they were on "clearance" at only $199 (just $490.46 today!).

As long as I'm waxing nostalgic...

I think my original system was as follows (with my best est/recollection on prices)

H8 $395
H19 $725
H17 $625
H-8-4 $250
WH-8-16 $299 (* 2)
HDOS $100

So that's almost $2,700, but I think these were discounted at least 20% if you bought a system, so let's call it $2,150.

I quickly found out that a 32K, 100K drive system was inadequate, so ordered a second drive ($395?) and 16K more RAM ($299), so that's about $2,850, which is about $7K today! But it was all worth it back then... :-) and next time I see an H8 sell for $700 on eBay maybe I won't be so surprised. They're among the coolest of the early computers...

- glenn

-----Original Message-----
From: se...@googlegroups.com [mailto:se...@googlegroups.com] On Behalf Of Lee Hart
Sent: Saturday, December 12, 2015 8:17 PM
To: se...@googlegroups.com
Cc: Norberto Collado <norberto...@koyado.com>
Subject: Re: [sebhc] New H8 Owner

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[Norberto Collado]

Pete's CPU Z80 board is not working either. I cannot get the ION LED/Front Panel to work. Any ideas? I will review the Z80 schematics to find out on how to get the ION LED to work. Picture attached!

Norberto

[Norberto Collado]

What I found is that the 444-70 ROM pin-out that is on the Heath Z80 board is different than the 2732 EPROM that I'm using on Les Z80 board with same image. Same principle applies to the 2732 PAM-37 EPROM. So I put back the 444-70 ROM and now I get the ION LED "on" but the front panel LEDs are off as well the MON LED. 

I do not see any interrupts coming from the H8 front panel, so the INT pin on the CPU is always high and the circuitry around this logic seems to be fine.

Norberto

-------- Original Message --------
Subject: RE: [sebhc] New H8 Owner
From: "Norberto Collado" <norberto...@koyado.com>

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[Norberto Collado]

The 444-70 is using the 2332 pin-out, so cannot use the 2732 EPROM... I manually injected the front panel interrupt, the speaker makes a little noise and that is it. It seems that it cannot write to the front panel I/O port. Replaced IC's related to such circuit and same behavior. :(

Norberto

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[Peter Clark]

Sounds like a good plan.   I have a couple of thoughts on the DG card.   It looks like it has bank enable switches, and I had turned off all but bank 0 while I was trying to debug it.   I also had put new chips in bank 0.   That could be why it doesn't seem to see all the ram.   Without a manual or schematic though, I wasn't sure if I was interpreting the switches correctly... 

On Saturday, December 12, 2015 at 12:29:56 PM UTC-6, Norby wrote:

Hello Pete,

[Peter Clark]

Very exciting!   Although I feel bad the thing was so messed up...   Why do you suppose someone would have put the wrong chips on it?    I think I may have noticed that the chips on the board didn't correspond to what was in the manual in a couple of cases, but I wasn't sure whether I just had a different version, or someone had mucked with it.   I had tried swapping in the right chips, but without a working CPU I wasn't able to see if it worked, so I put it back the way it was.   Good to know I was on the right track :) 

[Norberto Collado]

Yeap, wrong IC’s on the wrong sockets. A 7402 was in the 74LS74 socket (with the rework) and a 74LS74 was in the 74LS32 socket.  Because the data 74LS240 IC’s were overheating, that provided a glue on what was going on. I was lucky that Max has the same board  to get the 16K RAM board working again.

Without a working CPU and H8 front panel, I would be a nightmare for you to figure out the real issue. I will try to get the CPU working today if possible, so that I can return the boards tomorrow.

The Heath Z80 CPU is a weak design when compare with the Trionyx Z80 board. The Heath Z80 board “only” takes the 2332 ROM and I cannot update it to take the 2732 EPROM to upgrade it with PAM-37.

The DG board is very, very, and very unstable at Power-on. I did play with the switches and was not able to do better. Without any diagrams I cannot help that much. I rather order you the Les’ 64K RAM board, instead!

The goal is to get you a working Heath Z80 CPU and the Heath 16K board so that you can check the front panel to get your H8 operational on power-on. On the CPU I had to replaced several IC’s without that much luck so far. Hopefully I will be able to do a touch down on your Z80 CPU this morning as the Seahawks are playing right now.

Thanks,

Norberto :)

[dwight]

It seems like I recall an error on the schematic or silkscreen from a previous

post??

Dwight

---

From: se...@googlegroups.com <se...@googlegroups.com> on behalf of Norberto Collado <norberto...@koyado.com>
Sent: Saturday, December 12, 2015 12:23 PM
To: se...@googlegroups.com

Subject: Re: [sebhc] New H8 Owner

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[Peter Clark]

Hey Norberto, 

Are you talking about Les's H8-64 board?  I can get some manufactured.   He's got the gerber files on his site. 

I was also looking at his Z80/64k card.   that might be an option too.   What do you think?

Pete

p.s. no hurry on the boards - enjoy the football!   I'm going to owe you in a major way, sounds like these boards are/have been a lot of work.  

[Glenn Roberts]

Pete: you might be just the kind of guy with the energy to get an order of boards together!  A while back we were contemplating ordering some boards based on the designs that Les has on his site.  There was interest in backplanes, CPU cards, maybe more.  I am the fortunate owner of a system based on all new boards – and it runs very cool and very reliably.  Unfortunately I didn’t get to actually *build* those boards so I always wanted to go back and do another H8 rehab.

 

I took the action to help with that order, and (ashamedly !!) I dropped the ball.  I should be able to pull together the list of who was interested in what if you want to restart that discussion.

 

As I recall we got talking about all the great things we could do to redesign the CPU board, but nobody with the skill to do that had the time or interest to make it happen.  I’d certainly be interested in some boards if we started putting an order together.  I think it would be great to do another run of these.  It’s been quite a few years since the group did that!.

 

-          Glenn

 

From: se...@googlegroups.com [mailto:se...@googlegroups.com] On Behalf Of Peter Clark
Sent: Sunday, December 13, 2015 2:31 PM
To: SEBHC <se...@googlegroups.com>
Subject: Re: [sebhc] New H8 Owner

 

Hey Norberto, 

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[Les Bird]

Sorry I sent this directly to Peter instead of the group. Read below.

Hey Norberto, not sure if this will be any help but I played around with the DG Z80 board before and I got it working with the H37 card. Go here and scroll all the way down to the bottom. Hopefully this helps.

http://www.lesbird.com/sebhc/HeathkitCollection.html

Sent from Yahoo Mail for iPhone

--

[Peter Clark]

Hey Glen, 

I'd be glad to do that.   I don't have a ton of experience, but I have been working on building cards from John Monahan's designs for my IMSAI.   I've used pcbcart to have some of John's designs manufactured.   I'm assembling his Z80 SBC now in the hopes I can get that system up and running with CP/M 2 or 3 from a CF card.   I'd be glad to do a larger run of some of Les's H8 designs and mail them out if folks were interested. 

Pete

[Les Bird]

Also guys, I have a crap load of Rev 2.1 64K cards on hand. And by crap load I mean 33 of them. They quickly became obsolete when I created the H8-Z80-64K CPU card which had the 64K chip on the CPU board. If you guys need any let me know. I will part with them for $5/ea + $5 U.S. Priority Mail shipping (so $10 shipped).

On Sunday, December 13, 2015 at 4:05:12 PM UTC-5, Les Bird wrote:

Sorry I sent this directly to Peter instead of the group. Read below.

Hey Norberto, not sure if this will be any help but I played around with the DG Z80 board before and I got it working with the H37 card. Go here and scroll all the way down to the bottom. Hopefully this helps.

http://www.lesbird.com/sebhc/HeathkitCollection.html

Sent from Yahoo Mail for iPhone

On Sunday, December 13, 2015, 2:31 PM, Peter Clark <pec...@gmail.com> wrote:

Hey Norberto, 

Are you talking about Les's H8-64 board?  I can get some manufactured.   He's got the gerber files on his site. 

I was also looking at his Z80/64k card.   that might be an option too.   What do you think?

Pete

p.s. no hurry on the boards - enjoy the football!   I'm going to owe you in a major way, sounds like these boards are/have been a lot of work.  

  

On Sunday, December 13, 2015 at 12:24:25 PM UTC-6, Norby wrote:

Yeap, wrong IC’s on the wrong sockets. A 7402 was in the 74LS74 socket (with the rework) and a 74LS74 was in the 74LS32 socket.  Because the data 74LS240 IC’s were overheating, that provided a glue on what was going on. I was lucky that Max has the same board  to get the 16K RAM board working again.

Without a working CPU and H8 front panel, I would be a nightmare for you to figure out the real issue. I will try to get the CPU working today if possible, so that I can return the boards tomorrow.

The Heath Z80 CPU is a weak design when compare with the Trionyx Z80 board. The Heath Z80 board “only” takes the 2332 ROM and I cannot update it to take the 2732 EPROM to upgrade it with PAM-37.

The DG board is very, very, and very unstable at Power-on. I did play with the switches and was not able to do better. Without any diagrams I cannot help that much. I rather order you the Les’ 64K RAM board, instead!

The goal is to get you a working Heath Z80 CPU and the Heath 16K board so that you can check the front panel to get your H8 operational on power-on. On the CPU I had to replaced several IC’s without that much luck so far. Hopefully I will be able to do a touch down on your Z80 CPU this morning as the Seahawks are playing right now.

Thanks,

Norberto :)

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[Norberto Collado]

Thanks Les! I took a look at this already but the problem is that the DG 64K RAM board is unstable during power-on activities. If it comes on, it just works for a while and then it goes offline. It might take more than 10 power cycles to get it back. It doesn't make sense to work on it anymore due to its unique parts and lack of schematics. Also the CPU cannot find the whole 64K of RAM.

Peter,

Your Heath Z80 CPU is completely dead! I replaced 60% of the IC's and still dead. Also I have another Heath Z80 CPU in working conditions which I was planning to send you but ran into another road-block. The Heath Z80 CPU does not work with this version of the memory board at 0 ORG. It might work above 0 ORG. So I have a working Heath 16K board that does not run with a working Heath Z80 CPU. The Z80 CPU that I have works fine with my memory design (picture attached).

My recommendation is to get a group order of Les Z80 CPU with latest changes to which I will like to add another minor change. The Heath Z80 CPU is limited to only XCON-8 (2332) so it doesn't make sense to order Les 64K RAM board.

In the meantime you can borrow my Les' Z80 board to help you out with your H8 front panel debugging. The board has already RAM on board, so no need for external RAM. I will ship to you tomorrow and "only" Les' Z80 CPU so that you can "only" focus on the front panel debug activities. Send me your shipping address.

I will suggest to eventually sell the dead Z80 CPU board, the Heath 16K RAM (working condition now), and the DG 64K RAM board in Ebay to recover any expenses incurred in getting your system up and running.

Thanks,

Norberto

-------- Original Message --------
Subject: Re: [sebhc] New H8 Owner

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[Peter Clark]

Thanks Norberto, 

I shot you a note to your koyado email address.   I agree with your recommendation, although the perfectionist in me probably force me to still try to fix that original Heath z80 board.   I know it doesn't make sense, but I'm just weird that way....   

Glenn/Norberto/Les, Since I've not done these type/size of boards before I was thinking of doing a prototype run to make sure I can produce a working board.   After that I could do a production run for as many as folks want.   What do you guys think of that idea? The minimum prototype order is 5 for pcbcart.  If you guys like that idea - I only need one so I could send the other four to folks that would want to test it as well.   

Pete

[Glenn Roberts]

The H77 unit with the Miniscribe disks (about ¼ way down on that page) – that’s the same ACT system I’ve got.  You don’t by any chance have any of the software that went with that do you Les?

 

-          Glenn

 

 

From: se...@googlegroups.com [mailto:se...@googlegroups.com] On Behalf Of Les Bird
Sent: Sunday, December 13, 2015 4:05 PM
To: SEBHC <se...@googlegroups.com>
Subject: Re: [sebhc] New H8 Owner

 

Sorry I sent this directly to Peter instead of the group. Read below.

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/89026715.458864.1450040710764.JavaMail.yahoo%40mail.yahoo.com.

[Les Bird]

Glenn, no I never could get them to work to get the software off. They sure are loud though.

Sent from Yahoo Mail for iPhone

[Glenn Roberts]

Well I got that second H89 working today so in a moment of bravery I fired up the drives.  They’re noisy but on my unit that’s mostly the fan!  I only have one HDOS disk with the HD: driver on it.  I tried mounting all 8 units and they all failed.  Just never returns from the Mount command.  The disk activity light comes on solid and never goes out.

 

Without the test utilities for this drive I’m not going to get anywhere. 

 

If I had a boat I’d now have a new anchor…

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[Norberto Collado]

Glenn,

Which controller it uses on the H89 computer?

Norberto

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[dwight]

Unless I'm wrong, a 2332 to 2732 adapter is just two machine pin sockets and a little

wire.

Dwight

---

From: se...@googlegroups.com <se...@googlegroups.com> on behalf of Norberto Collado <norberto...@koyado.com>

Sent: Sunday, December 13, 2015 7:16 PM
To: se...@googlegroups.com

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/20151213201643.1321cca37f09b4ab87c5049afdc8ceaa.275c016c9b.wbe%40email09.secureserver.net.

[Norberto Collado]

Correct!

Norberto

On 12/13/15 8:57 PM, "dwight" <dke...@hotmail.com> wrote:

[Glenn Roberts]

it uses a very simple card in the H89. only a few bus interface chips.  all the smarts are in the ACT controller board which lives in the H77 chassis on top of the drives.  I can post more information soon...

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[Norberto Collado]

I hope you can get the setup to work to find out what is inside the hard drives. Any technical information on such solution will be great and a picture of the H89 controller as well. 

Let me know on how I could help. 

[Glenn Roberts]

Peter: I forget what the approximate cost is per board but I’m good for two if they’re priced right.  I’ve got two 8080-based H8s that I’d like to eventually upgrade; will probably sell one (or both?) once I get it modernized.  The key to any enhancement (speedup, Z67-IDE, H37 interface, etc.) is to have a Z-80 based CPU board…

 

So we’d need two other interested parties to get an order of 5 going…

 

-          Glenn

 

 

From: se...@googlegroups.com [mailto:se...@googlegroups.com] On Behalf Of Peter Clark
Sent: Sunday, December 13, 2015 7:21 PM
To: SEBHC <se...@googlegroups.com>
Subject: Re: [sebhc] New H8 Owner

 

Thanks Norberto, 

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[Max Scane]

Hi Please put me down for one.  I have a H8 with 1 x 16KB and 2 x 8KB memory modules, Cassette/serial card, Parallel card and H17.

I'd be keen to update to a Z80 card.

Thanks!

Max

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[Glenn Roberts]

On the ACT dual hard disk external unit for the H89 (that I previously declared a boat anchor): I’m willing to probe a little further…  it’ll be tough to make progress without the CP/M disks, which had a rich set of utilities and test code, all in source format.  The only piece I have is HD.DVD – the HDOS device driver.

 

So being a glutton for punishment, and a bit of a disassembly nerd, I reverse engineered the code through disassembly.  First clean pass at that (it re-assembles to the same code) is attached.  Apologies to Z80 fans, this is in split octal (and I had to fake out the three Z80 instructions).

 

It appears this unit is much less sophisticated than the H67.  I don’t think it even has a partition table, it looks like the driver just chunks each drive into four equal pieces (two drives, so 8 total HD: devices).

 

The command sequence is simple enough.  I may set up a Turbo Pascal disk and play with a couple simple programs to see if I can talk to the drives…

 

-          Glenn

 

 

From: se...@googlegroups.com [mailto:se...@googlegroups.com] On Behalf Of Norberto Collado
Sent: Monday, December 14, 2015 2:03 PM
To: se...@googlegroups.com
Subject: RE: [sebhc] New H8 Owner

 

I hope you can get the setup to work to find out what is inside the hard drives. Any technical information on such solution will be great and a picture of the H89 controller as well. 

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[Norberto Collado]

WOW and great work in reversing engineering the HDOS device driver. Before they become a boat anchor again, the only thing I can do is to add code to the Z67-IDE+ to download from the MFM hard drives sector by sector into the CF cards connecting such drives into the Xebec controller. It is on my to do list as a tool to preserved historical data.

I’m still interested in getting a picture of the H89 controller that your setup is using when you get a break.

Great work!

Norby

On 12/21/15 7:08 PM, "Glenn Roberts" <glenn.f...@gmail.com> wrote:

[Glenn Roberts]

It seems the power supply is dead at the moment.  The unit came with detailed instructions on how to modify the standard H77 power supply to beef it up (new bridge rectifier and regulators).  Right now I don’t seem to be seeing any voltage on the transformer secondary.  Need to pull things apart a bit to take some measurements…  Maybe I’ll try Les’ light bulb trick!

 

Part of the retrofit is to install a cooling fan.  This one is noisy (I think the bearings are shot). It’s wired directly to the power supply (not switched!) so the fan basically ran all the time the unit was plugged in.

 

So since I’ve got things disassembled I took some pix of the controller card (attached). 

 

The card in the H89 is very simple, just buss interface chips.  It’s attachment number 6.  The chips (from left to right) are 74LS241N, 74LS241N, 74LS244N and 74LS32N.  The manual brags that one feature of this system is that you can easily take it with you when you upgrade to a new computer as the interface card is very simple (and presumably inexpensive)…

 

-          glenn

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[Alan Hampson]

Does anyone else recognize IMG_3310? 

There were several of these on eBay (e.g. http://www.ebay.com/itm/VINTAGE-HEATH-ZENITH-HEATHKIT-I-O-BOARD-MODULE-5MH89-POSSIBLY-DISK-I-O-H89-/371272052255) a while back and there was quite a discussion about what they were and what they'd connect to.

Sorry, but it just triggered my geek coolmeter!

alan

[Steven Hirsch]

On 12/22/2015 10:11 PM, Alan Hampson wrote:

> Does anyone else recognize IMG_3310?

> There were several of these on eBay (e.g.
> http://www.ebay.com/itm/VINTAGE-HEATH-ZENITH-HEATHKIT-I-O-BOARD-MODULE-5MH89-POSSIBLY-DISK-I-O-H89-/371272052255)
>
>a while back and there was quite a discussion about what they were and what
> they'd connect to.

I picked up one of those boards, but have no idea what it's for.

[Norberto Collado]

That is the same one that Glenn is using to drive the ACT dual hard disk
unit.

Norberto

[Glenn Roberts]

Correct.

-----Original Message-----
From: se...@googlegroups.com [mailto:se...@googlegroups.com] On Behalf Of Norberto Collado
Sent: Wednesday, December 23, 2015 1:28 AM
To: se...@googlegroups.com
Subject: Re: [sebhc] New H8 Owner

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[Peter Clark]

Hi All, 

I've been going through my front panel with Norberto's working Z80/64k cpu card.   The CPU and front panel is all that I have in the computer at this time.    I've read through the explanation of the startup sequence in the Heathkit manual, and have been going through this on the schematic and trying to figure out why I get only power and run lights on the front panel.   I may need some remedial help, as I can't figure out what is going on. 

I'd appreciate it if anyone has some guidance on how to proceed.   It looks to me like the startup sequence is working up through the point at which IC112 pin 3 goes low to generate an interrupt to the CPU.   At that point the CPU is supposed to generate an IOW to address 360 and from what i've read that should clock IC102 & 106 but I don't seem to be picking up the IOW and the INT10 line stays low.   

Please have a look at the diagram of what I'm seeing and let me know if this illustrates what's going on.   I've overlayed some screen shots of the scope traces I've taken, along with labelled in red high/low.  I'd be glad to take other measurements, or document a different way if that would help. 

Click to blow up the image. 

Thanks in advance, I'm really pulling out my hair on this one.   

Pete

On Saturday, December 12, 2015 at 12:29:56 PM UTC-6, Norby wrote:

Hello Pete,

The Heath 16K RAM is completely dead. The DG board is unstable on power-on and it does not see the complete 64K of RAM (picture attached). I'm going to focus on the 16K RAM first to get it working.

Thanks,

Norberto 

[Norberto Collado]

Peter,

I’m available until next Sunday Jan 3rd, 2016 if you want to send me the front panel along with the Z80/64K CPU so that I can test it on my H8.

Thanks,

Norberto

On 12/24/15 9:07 AM, "Peter Clark" <pec...@gmail.com> wrote:

Hi All, 

I've been going through my front panel with Norberto's working Z80/64k cpu card.   The CPU and front panel is all that I have in the computer at this time.    I've read through the explanation of the startup sequence in the Heathkit manual, and have been going through this on the schematic and trying to figure out why I get only power and run lights on the front panel.   I may need some remedial help, as I can't figure out what is going on. 

I'd appreciate it if anyone has some guidance on how to proceed.   It looks to me like the startup sequence is working up through the point at which IC112 pin 3 goes low to generate an interrupt to the CPU.   At that point the CPU is supposed to generate an IOW to address 360 and from what i've read that should clock IC102 & 106 but I don't seem to be picking up the IOW and the INT10 line stays low.   

Please have a look at the diagram of what I'm seeing and let me know if this illustrates what's going on.   I've overlayed some screen shots of the scope traces I've taken, along with labelled in red high/low.  I'd be glad to take other measurements, or document a different way if that would help. 

Click to blow up the image. 

 <https://lh3.googleusercontent.com/-0FzJ3Tcp-IA/VnwltdMfIBI/AAAAAAAACCM/qXLIe8i7Y8A/s1600/h8-diag.jpg>

Thanks in advance, I'm really pulling out my hair on this one.   


Pete


On Saturday, December 12, 2015 at 12:29:56 PM UTC-6, Norby wrote:

[Peter Clark]

Hey Norberto, 

I'd really like to get this working myself, I really enjoy working on these computers.  It gives me a chance to learn about how they work in much greater depth.   I may have to throw in the towel and take you up on your offer, but I'm hoping with a little guidance I can figure out what's going on.   

Any ideas on what to look at next?  From what I can tell it doesn't seem like the IO write to 360 is occurring to start the interrupts from the front panel.   The clock signal and the subsequent circuit for it.   I've replaced almost every chip on the board, the only two I haven't are the 74148 chips that encode the keys.   All the chips test good.   Power supply +5 volts is not noisy.  

There doesn't appear to be any modifications to the front panel board, all the components match the manual I have.   I've replaced the filter caps.   

The only other thing I can think of is the buss / edge connectors.   They appear to be making good contact, but could that be an issue?   I'm wondering if I should clean or repin them.   Is that a common issue with these computers? 

[Glenn Roberts]

Peter: do you have the gold plated buss pins or the (earlier) tinned ones?  There were some issues with the tinned ones –Heath went to gold plated for subsequent models.

 

From: se...@googlegroups.com [mailto:se...@googlegroups.com] On Behalf Of Peter Clark
Sent: Saturday, December 26, 2015 10:29 AM
To: SEBHC <se...@googlegroups.com>
Subject: Re: [sebhc] New H8 Owner

 

Hey Norberto, 

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[Peter Clark]

They look like gold plated to me.   Here's a pic (kinda hard to tell from the picture, but they look much more gold in person). 

I restore pinball machines and arcade games as well, and I sometimes use Deoxit on interconnect pins that are not making good contact due to oxidization.  http://store.caig.com/s.nl/it.A/id.1610/.f?sc=2&category=188     I haven't tried this yet, but it's a lot easier than re-pinning all the connectors.  Any thoughts?

Another thought I had was if I needed to change any settings on Norberto's Z80/64k card.   Would there be any changes needed if I just have the z8064 card and my front panel?   Here's a pic of the current jumper/switch settings.   Would any of these need to change for just this card/front panel (ie. no disk/serial port/etc)?

I have the 74148 keyboard encoders removed in this picture of the front panel

 

Pete

[John Toscano]

DeOxit is great stuff. Cheapskates like me get almost as good results by using its main ingredient, mineral oil, which can be bought at most pharmacies.

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[Glenn Roberts]

Yep. Looks good.  Seems unlikely to be the source.  Silly question but I presume you’ve verified that the plugs for the front panel are inserted correctly into the buss?

 

From: se...@googlegroups.com [mailto:se...@googlegroups.com] On Behalf Of Peter Clark
Sent: Saturday, December 26, 2015 12:32 PM
To: SEBHC <se...@googlegroups.com>
Subject: Re: [sebhc] New H8 Owner

 

They look like gold plated to me.   Here's a pic (kinda hard to tell from the picture, but they look much more gold in person). 

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[Peter Clark]

not a silly question :-)  as I have done that before.   I will double check but I've been pretty careful since that first screwup... 

[Peter Clark]

that's a great tip.   I never even bothered to check what was in the stuff.   

[Peter Clark]

I finally figured out the problem.   I was going back through everything on the board, focusing on the connectors, etc., and discovered A6 was not testing connectivity to the buss.   The wire tested good, but no contact to the buss.   I took the pin out of the connector, and it looks like the end of the pin had broken off inside the connector. 

I crimped a new pin on, and reconnected the connector and it worked!  I'm guessing all the plugging and unplugging of the front panel as I working on it finally took it's toll on these old pins.   

woohoo!

Thank you so much for loaning me your Z80 card Norberto!   It made all the difference.   

[Kenneth L. Owen]

Hi Peter,

 

Congrats!  Your dogged persistence paid off and made me re-visit a previous note included below.

 

Maybe it needs to be added as another step:

 

      7A. If the problem is not found, loop back through the plan to see what you may have overlooked!

 

-- ken

---

From: Kenneth L. Owen [mailto:tx83...@bellsouth.net]

Sent: Friday, December 18, 2015 3:35 PM
To: 'se...@googlegroups.com'

Subject: RE: [sebhc] Re: Another New H8 Owner - Standalone RAM Diags - Power Transformer needed.

 

Hi Jason,

 

You just demonstrated most of the proper discipline for working on these old machines:

 

1. Patience
2. Thoroughness of testing
3. Start at the beginning (PS) and work up
4. A good plan
5. Sticking to the plan
6. Attention to detail
7. Analyzing the results at every juncture
8. Enjoying the result of completing the plan.

 

Congratulations on your success!!!  It was well earned.

 

-- ken

 

 

---

From: se...@googlegroups.com [mailto:se...@googlegroups.com] On Behalf Of Peter Clark
Sent: Saturday, December 26, 2015 11:59 PM
To: SEBHC
Subject: Re: [sebhc] New H8 Owner

 

I finally figured out the problem.   I was going back through everything on the board, focusing on the connectors, etc., and discovered A6 was not testing connectivity to the buss.   The wire tested good, but no contact to the buss.   I took the pin out of the connector, and it looks like the end of the pin had broken off inside the connector. 

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[Glenn Roberts]

Great news.  Always good to see another H8 come back to life!

 

From: se...@googlegroups.com [mailto:se...@googlegroups.com] On Behalf Of Peter Clark
Sent: Saturday, December 26, 2015 11:59 PM
To: SEBHC <se...@googlegroups.com>
Subject: Re: [sebhc] New H8 Owner

 

I finally figured out the problem.   I was going back through everything on the board, focusing on the connectors, etc., and discovered A6 was not testing connectivity to the buss.   The wire tested good, but no contact to the buss.   I took the pin out of the connector, and it looks like the end of the pin had broken off inside the connector. 

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[Norberto Collado]

Hello Peter,

Great job in isolating the issue and nice x-mas present to have your H8 front panel operational again. You had CPU, memory and front panel issues, and no way to be able to get your H8 operational with such combination of bad boards. Next step will be to add your H17 board and be able to boot HDOS. I think this will run smoothly. Just press 1 (primary) on the H8 front panel to boot from the H17 and hope for the best!

Do not forget to add the cable to the H17 board to select side 2 of the floppy drive. I did send you a picture of the rework before.

Also I will encourage to add another red LED and resistor to the H8 front panel (left top side of the H8-FP board). I wired this LED to my H8-67 controller to monitor the Z67-IDE activity when booting from the CF cards.

Best Regards,
Norberto

On 12/26/15 8:58 PM, "Peter Clark" <pec...@gmail.com> wrote:

I finally figured out the problem.   I was going back through everything on the board, focusing on the connectors, etc., and discovered A6 was not testing connectivity to the buss.   The wire tested good, but no contact to the buss.   I took the pin out of the connector, and it looks like the end of the pin had broken off inside the connector. 

 <https://lh3.googleusercontent.com/-jIlb_77djiM/Vn9tM4MfxJI/AAAAAAAACDk/3-nspM6tiRc/s1600/IMG_9526.JPG>

I crimped a new pin on, and reconnected the connector and it worked!  I'm guessing all the plugging and unplugging of the front panel as I working on it finally took it's toll on these old pins.   

 <https://lh3.googleusercontent.com/-29X1P2nrw1A/Vn9tZrqvtOI/AAAAAAAACDs/w5-4UzvIfxM/s1600/IMG_9527.JPG>

[Glenn Roberts]

I concur with the advice to add the 5^th led in the unused position on the front panel board.  I also connected that to my Z67-IDE+ activity light and it is very handy to know when your system is accessing the disk this way.

 

From: se...@googlegroups.com [mailto:se...@googlegroups.com] On Behalf Of Norberto Collado
Sent: Sunday, December 27, 2015 3:25 PM
To: se...@googlegroups.com
Subject: Re: [sebhc] New H8 Owner

 

Hello Peter,

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[Peter Clark]

Well, getting the H17 working wasn't quite as straightforward as I had hoped. :-(  The H17 controller passes its tests in the computer (from the manual), but 2 of the 3 drives in my H17 disk unit smoked their controller boards within the first few seconds of the tests.   

Before I did much more, I spent about 3 hours completely disassembling the 3rd drive, cleaning, checking all the wires etc, and lubing and reassembling it.  I'm going to have some more work to do on this before it's working.   The drive motor test works, but the head solenoid doesn't engage on that test. 

This should have probably been more obvious to me, but one thing I've learned: MICE + FLOPPY DRIVES = NOT GOOD^2 

Those little buggers made quite a little home for themselves in this H17.   They gnawed on lots of wires, and peed all over everything.    In retrospect, if I knew what I know now about this H17 when I started, I'm not sure I would have.   The gold plated wires coming from some of the leds just literally came apart as I pulled the connector off them.   It's amazing the corrosion mouse pee can cause.   They gnawed almost through one of the belts... Wow... 

I may be able to make one good drive from the parts from the 3 of them.   

Good news: 

The case cleaned up fairly well and the power supply works good.   After the Evaporust, and wirebrushing etc here's what it looks like... I repainted the case with Rustoleum black hammertone paint.   I used a nickel finish on the inside to cover up the pitting from the mouse pee rust.

 

Pete