H8 Backplane/Motherboard

[Les Bird]

Ok,

 

This is my first (final?) pass at the H8 backplane/motherboard. I doubled up the plug-in connectors and added 2 options for power source. Option 1 is the original H8 power which has taps at the bottom for the wires and option 2 is a PC-style power supply. Note that even though option 2 is wired for a PC-style power source you can actually wire in ANY type of power supply there so long as you use a compatible Molex connector plug. So Chris, your recommendation for a 3rd party power supply can certainly be realized with this design.

 

This, along with my other H8 PCBs, is the final piece to be able to assemble a complete (minus chassis) H8 computer. As Chris suggested earlier, one could build an open air H8 or put together a plexiglass chassis for it.

 

Any comments?

 

- Les

 

[Bill Loguidice]

Yes, how much for a full setup? ;-)

 

====================================================
Bill Loguidice, Managing Director
Armchair Arcade, Inc.
http://www.armchairarcade.com
A PC Magazine Top 100 Website
====================================================
Authored Books: http://www.armchairarcade.com/books
====================================================
LinkedIn: http://www.linkedin.com/in/billloguidice
====================================================

[Les Bird]

Bill,

 

I'll let you know when I get these things priced out. Stay tuned...

 

- Les

[Les Bird]

H8-BP (backplane/motherboard) prototypes check out. The attached pictures show a H8 computer powered using a 450 watt $30 ATX power supply. All that is required is to strap the voltage in/out of each board in the system (photo shows how I did it on the Z80 CPU card). The ATX power supply is a much better solution for powering the H8. First, it is a proven power supply. Second, they are cheap, powerful and plentiful. Third, when you turn it on the power is there and when you turn it off the power is off - there's no slow power up or waiting for parts to charge and when you turn it off you don't get the fade-out effect on the front panel like you do with the original power source. It's a nice clean on/off solution. And I won't even mention the weight difference (those H8 transformers are heavy)! Plus most of them have a built-in fan for cooling down the system (if you mount it inside the chassis) but without the hot regulators on the boards it's a much cooler running H8 system.

 

The price for all the components is as follows:

 

H8-Z80-64 Rev 2 - $40

H8-17 - $30

H8-4 - $30

H8-FP (front panel) - $40

H8-BP (backplane/motherboard) - $40

 

The Z80 boards have already been shipped and I should have the 1st batch by tomorrow. The front panels have been ordered (15 of them) and should be here in about a week and a half. I'm placing an order for 15 backplanes this week and should have the final versions in a couple weeks. In the photo you see the ATX power connector at the top-rear of the backplane. In the final versions I moved it down to the bottom so it won't interfere with the cable access slot.

 

This is the final piece for building a complete H8 system. For chassis solutions you could try building Chris' plexiglass box idea or try using a PC tower case (which is something I plan to explore later) or maybe try this all aluminum case from Newark:

 

http://www.newark.com/bud-industries/ac-1429/ac-series-chassis/dp/06M4378

 

- Les

 

[Chris Elmquist]

Excellent work Les. It's very cool (literally!!).

Is there nothing in the H-8 that requires +/- 18V?? I thought those rails
were also provided by the original supply. If so, how are you coming up
with that from the PC supply? Or were all of the 18V rails immediately
regulated down to 12V and you are bypassing those regulators too?

I suppose a guy could make a really nice hardwood case too... some hand
rubbed cherry or walnut maybe? :-)

I'll place an order for all the boards very soon.

Chris

--
Chris Elmquist

[Les Bird]

Chris,

The +/-18V supplies were regulated down to +/-12V and I bypass those
regulators too. I've found that those were only used with the H8-4 serial
card though and maybe the original 8080 card too.

- Les

----- Original Message -----
From: "Chris Elmquist" <chris.e...@gmail.com>
To: <se...@googlegroups.com>
Sent: Wednesday, September 16, 2009 8:14 PM
Subject: [sebhc] Re: H8 Backplane/Motherboard

[Jack Rubin]

My thought was to simply substitute plexi side panels for the original
plastic foam issue and add a flat slab top with some ventilation slots but
not louvers. I figure to keep the original sheet metal front, bottom and
back for simplicity and mechanical strength.

The replacement side panels will need threaded inserts similar to those in
the originals. I don't have any experience with CAD so I'm not sure about
how to lay these out mechanically. I thought I'd just take a pair of side
panels to a fabricator and see how much it would cost to reproduce them in
plexi. Given the thickeness, it probably won't be cheap. I guess the new
sides could be a little thinner, but they would still need to be able to
hold the inserts for the back, bottom and front panels.

Any thoughts?

Jack

> -----Original Message-----
> From: se...@googlegroups.com [mailto:se...@googlegroups.com]
> On Behalf Of Les Bird

> No virus found in this incoming message.
> Checked by AVG - www.avg.com
> Version: 8.5.409 / Virus Database: 270.13.100/2373 - Release
> Date: 09/16/09 11:21:00
>

[Les Bird]

Jack,

I used the eMachineShop CAD software to layout all the parts for a complete
H8 chassis. The sides for one piece in transparent polycarbonate would run
about $175.50 for quantity 10 ($17.55 ea) or $269.12 for quantity 20 (about
$13.45 ea). These are sides with no holes drilled, just cut to shape. To add
holes would really jack the price up so it'd be better to just drill them
yourself. Here's the price for the rest of the parts:

Front with hole cut for keypad (but not for LEDs - it's transparent so not
necessary): $21/ea for 10 or $14/ea for 20
Top with no vents cut: $19/ea for 10 or $15/ea for 20
Bottom with no vents cut: $29/ea for 10 or $24/ea for 20
Back with no holes drilled or cut: $17/ea for 10 or $13/ea for 20

I wasn't planning on ordering any of this so if someone wants to move
forward with this idea then I'd be happy to hand over my eMachineShop
designs. You really have to buy in quantities to get the price down.

My plan was to go to Lowe's and get a couple sheets of 1/4" plexiglass and
cut the pieces myself. I do think that a transparent chassis would look
really nice though (blame Chris for planting this in our heads!!).

So by the way guys, after using my gutted H8 with all new PCBs and the ATX
power source I have to say, it is the smoothest running H8 system I have.
Everytime I power it up it is ready to go. Usually with my first gen Z80
card I have to do a RST/0 (somtimes more than once) to get the thing to
behave when I power up but not with this setup. It powers up perfectly
everytime. I'm not sure if it's because I have all new PCBs and connectors
or if the power supply is cleaner or what, but I have definately noticed a
difference. Top that off with no regulators and not only is it smoother but
a lot cooler too! Once I work out a way to mount the power supply in my
gutted H8 chassis and get it looking clean it will be my primary system.

[West, Ronald S.]

Les,

 

Cool. Do you spend all your time in the lab? Has the wife filed papers yet <hehe>?

 

Without the transformer and brute force PS in there does the ATX supply fit in the H8 case?

 

 

Ron

---

From: se...@googlegroups.com [mailto:se...@googlegroups.com] On Behalf Of Les Bird

Sent: Wednesday, September 16, 2009 5:30 PM

To: se...@googlegroups.com
Subject: [sebhc] Re: H8 Backplane/Motherboard

[Bill Loguidice]

OK, here's the million dollar question - or at least the thousand dollar
one... Assuming someone was willing, what do you think it would cost for
someone to provide either a 100% complete pre-assembled new unit for sale,
or a mostly assembled new unit (where the "dummy" buyer would just have to
screw together the case and plug the board and cables in) for the
electronically/electrically untalented such as myself? I'm talking a fully
loaded modern day H8 unit based off of the work below.

====================================================
Bill Loguidice, Managing Director
Armchair Arcade, Inc.
http://www.armchairarcade.com
A PC Magazine Top 100 Website
====================================================
Authored Books: http://www.armchairarcade.com/books
====================================================
LinkedIn: http://www.linkedin.com/in/billloguidice
====================================================

[Les Bird]

Ron,

 

I spend too much time in the lab but I can't help it.

 

The ATX power supply is not a clean fit for the original chassis. The dimensions are just slightly off and the orientation of the fan and power switch make it hard to get it in there properly. It would have to sit flat with the fan facing up and would render the last 2 or 3 slots of the backplane unusable. But that might be ok if you use those slots for short cards or don't use them at all.

 

I've seen custom ATX power supplies out there that are very small that would fit though. You'll have to order them online and when I find a source for them I'll post it. For a quick and dirty test (and to prove the concept) I just went and picked up a cheap full size supply at CompUSA.

 

- Les

[West, Ronald S.]

Les,

 

Thanks for the info. I have a couple more questions. Have you tried your new Z80 board at higher speeds and does the board have any provisions on it for changing processor speed?

 

Also, I like the suggestion someone made of nice cherry wood side panels. That would make it one sweet looking thing.

 

Ron

 

---

From: se...@googlegroups.com [mailto:se...@googlegroups.com] On Behalf Of Les Bird

Sent: Thursday, September 17, 2009 10:20 AM

[dwight elvey]

<003101ca379f$a46f5d50$2101a8c0@lesbird>
Content-Type: text/plain; charset="Windows-1252"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0

----------------------------------------
> From: les...@bellsouth.net

> To: se...@googlegroups.com
> Subject: [sebhc] Re: H8 Backplane/Motherboard

> Date: Thu=2C 17 Sep 2009 10:03:30 -0400
>
>
> Jack=2C
>
> I used the eMachineShop CAD software to layout all the parts for a comple=
te
> H8 chassis. The sides for one piece in transparent polycarbonate would ru=
n
> about $175.50 for quantity 10 ($17.55 ea) or $269.12 for quantity 20 (abo=
ut
> $13.45 ea). These are sides with no holes drilled=2C just cut to shape. T=

o add
> holes would really jack the price up so it'd be better to just drill them
> yourself. Here's the price for the rest of the parts:
>

Hi
Drilling plexiglass is not easy=2C even with a plexiglass drill.
One should clamp it between two pieces of plywood and drill
slow so as to not overheat it. The two pieces of wood are to
help stop breakouts that happen easily. A drill press is best used.
Dwight
=0A=
_________________________________________________________________=0A=
Bing=99 brings you maps=2C menus=2C and reviews organized in one place. =
Try it now.=0A=
http://www.bing.com/search?q=3Drestaurants&form=3DMLOGEN&publ=3DWLHMTAG&cre=
a=3DTEXT_MLOGEN_Core_tagline_local_1x1=

[Les Bird]

Bill,

Let's lay out what I think a fully loaded H8 would be:

H8-Z80-64 w/GIDE and 64K of RAM
H8-4 multi serial port card
H8-17 disk controller
H8-FP front panel
H8-BP backplane

The PCBs alone would be $180. Let's just say the cost for parts on average
is about $50 for each card, so that's $250. Throw in $10 for GIDE chips, $50
for the ATX power supply, $100 for a hard drive (probably overkill but let's
use ballpark figures). So for a complete open air chassis H8 fully assembled
you're looking at roughly $600. Now add in the chassis components based on
the quantity 10 pricing below, about $100 but let's just call it $150.

So you're looking at a total of about $750 for a transparent chassis H8
fully assembled with hard drive. I'm sure there are other costs to add in
too like brackets and stuff which I don't have a solution for at this time.

As I said before I wasn't planning on moving forward with the polycarbonate
chassis. You have to buy in quantities for the chassis to get any kind of
reasonable price so that'll be $1000+ investment for whoever wants to move
forward with that idea.

[Les Bird]

Ron,

 

The Z80 board is clockable but I haven't had any luck at over 2mhz. I've been able to power up the card at 4mhz but can't boot because the H17 won't run at higher than 2.

 

Oh and the cherry wood idea was Chris. Maybe he should be in charge of chassis design since all his ideas are so well received.

[Bill Loguidice]

Plus the labor and time for whoever if willing to build and sell it. So,
even without a case, you're probably talking $1000 for a fully loaded
pre-built system where you supply your own case and power supply. Still,
it's more than competitive for what a working original loaded like that
sells for and it will probably last longer.

[Jack Rubin]

Bill,

If you're not in much of a hurry and are willing to absorb all costs (i.e. shipping, etc.) to purchase a set of boards and components, I'll be glad to assemble them for you for beer money. I won't do anything about a chassis at this point, but I'd like to build out a full set and see how it works.

Jack

----- Original Message ----
> From: Bill Loguidice <bi...@armchairarcade.com>
> To: se...@googlegroups.com
> Sent: Thursday, September 17, 2009 9:55:08 AM
> Subject: [sebhc] Re: H8 Backplane/Motherboard
>
>

[Bill Loguidice]

You're on Jack! ;-) I'll keep watching the progress.

[Glenn Roberts]

But I suspect most on this list are like me: far more valuable is to have a
box full of parts and get to put it together yourself! Pre-assembled PC's
are a dime a dozen.

Wish I could reconstruct what I paid for my system. It was a pretty minimal
H8, I want to say 32K RAM, H19, 1 hard sector disk drive in an H17 cabinet.
That was probably still over 2 grand I think? (and 30 years ago!) That's
about $6K in 2009 dollars! And then of course I quickly figured out I
needed another 16K of RAM... and a second drive - I think those were maybe
$300 each back then? So that's like $7,500 total in today's dollars. But I
was young and single and had the passion.

Back then to actually build, own and operate your own digital computer was,
as MasterCard would say, priceless...

- Glenn

[Eric]

I remember I paid approximately $1,000 for my DG 64K RAM card. I
remember telling the Heathkit store owner that CP/M would only access
32K and he said that someday they would break that barrier and that I
would be glad to have the extra memory.

> Armchair Arcade, Inc.http://www.armchairarcade.com

> ...
>
> read more »- Hide quoted text -
>
> - Show quoted text -

[Les Bird]

Ron and all,

 

I found a nice 320 watt MicroATX power supply that fits inside the H8 chassis. It's the Diablotek PSDA320 and I got it from the local CompUSA store for $19.99. I think Newegg has them too. I've attached photos.

 

- Les

 

----- Original Message -----

From: West, Ronald S.

To: se...@googlegroups.com

Sent: Thursday, September 17, 2009 10:04 AM

Subject: [sebhc] Re: H8 Backplane/Motherboard

[Chris Elmquist]

On Thursday (09/17/2009 at 10:50AM -0400), Les Bird wrote:
>
> Oh and the cherry wood idea was Chris. Maybe he should be in charge of chassis design since all his ideas are so well received.

Ha! ya... I'm real good at tossing out ideas but poor on execution.

If somebody has an H8 chassis that has no electronics in it... and the
ability to take some pictures of the seperate pieces of it... that would
be real handy.

If we get real serious here and someone wants to loan me an empty chassis,
I would use it to take down all the dimensions and then shop them around
to various plastic and metal fabricators to see what kind of deal we
might be able to get.

I think it would be fun to make an aluminum base+sloped front panel and
top and perhaps thin gauge sides to which you could laminate some wood
veneer of your choice and stain+varnish to suit.

I am totally H8 challenged so I do not have any of these pieces myself to
know their design, dimensions and form+fit. But I am willing to learn!

I don't think any of the docs we have online are going to have dimensions
of the chassis components will they? That's why I'm thinking a guy
needs the real thing to take measurements...

Chris

--
Chris Elmquist

[steve shumaker]

Just something to consider...

Instead of trying to recreate the original, why not simply pick new
values for cabinet xyz dimensions. It wouldn't need to match the
original - it would only need to be at least the same or larger. If
Les has a 3d layout of the backplane and cards when connected, one could
start with that and make sure that the appropriate volume is available.....

2 cents worth... back to lurking now

s shumaker

[Chris Elmquist]

I think this is reasonable too Steve although I suppose if one wasn't very
interested in a replica, then you could find an off the shelf enclosure,
similar to what Les has found, and use that.

I guess I had replica on my mind and was thinking that if we went to
the effort of having someone fab something, we'd want to make it as much
like the original as possible... but then make some small changes to
accomodate mods like the clear sides and front or wood side panels.

Chris

--
Chris Elmquist

[Jack Rubin]

I'm interested in doing clear side panels - if others are interested in side
panel blanks ONLY - undrilled, no other parts, then I could go ahead with a
group order as Les quoted. Otherwise, I'll just do a set for myself locally,
though if anyone has a set of drawings done that would be helpful. Lacking
drawings, I'll just take a set of side panels to a local fabricator and ask
them to do set. I'll also do some sort of clear top, but it will just be a
simple flat top with vent slots and a couple of small stops to locate it.

Jack

> -----Original Message-----
> From: se...@googlegroups.com [mailto:se...@googlegroups.com]

> No virus found in this incoming message.
> Checked by AVG - www.avg.com

> Version: 8.5.409 / Virus Database: 270.13.107/2382 - Release
> Date: 09/20/09 06:22:00
>

[Les Bird]

Jack,

I did all the measurements for all the pieces in eMachineShop's CAD program.
Let me see if I can export them to a more common format. If not, I'll be
happy to forward what I've done to whoever wants to take it over. I would
certainly like to see this through myself but this is not a good time of
year for my line of work (products done in time for Christmas) so my funds
will be very limited until we can pick up more projects which usually
happens around February.

So if someone else is going to take over the chassis project sign me up for
one set.

My designs in eMachineShop CAD were for all clear polycarbonate pieces which
is cheaper than acrylic. In my front panel layout I had a cutout for the
keypad on the front panel but not for the LED display since it wasn't
necessary to do that with a clear front panel. It reduced the cost quite a
bit too.

- Les


----- Original Message -----

From: "Jack Rubin" <jack....@ameritech.net>
To: <se...@googlegroups.com>

[Les Bird]

I was able to export my chassis pieces to DXF format and I uploaded
the file, H8Chassis.zip, to the files section.

- Les

[steve shumaker]

Yes... that's one thought although it's actually more drastic than what
I was thinking. Seems to me, that it should be fairly simple to
recreate a case that looks almost the same as the original shape simply
by working from photos and using standard 3d design software... . The
"replica" feel would still be there - it just would have slightly
different dimensions. As you note, and IMHO, I definitely agree,
stuffing an H-8 inside some sort of modern "peecee' chassis misses the
point.

However in support of the original request, I have an unassembled
chassis kit, that if I recall, was an opened kit when I scored it. I
get back from my latest business trip on 30 Sep. I will look and see
if I can put my hands on it readily. If so, I will see what I can do
about some measurements and/or images.

steve

[steve shumaker]

Ok then! will that pkg export to AutoCad? As in DWG/DXF files?

steve

[steve shumaker]

oops sorry I should prolly start reading from the end of the thread!

[Les Bird]

Just an update about the backplanes.

 

I did receive the backplanes last week but when I moved the 24 pin ATX power connector to the bottom of the PCB I mis-wired it. This resulted in a blown ATX power supply when I plugged it in. All the traces were one pin to the right of where they should be. This can be salvaged by clipping the top/bottom right pins of the 24 pin connector and soldering it to the right by one pin but it covers up one mounting hole on the PCB. I'm submitting a new corrected design today but this will delay the backplanes by 2 weeks.

 

The current batch of backplanes that I have now will work as a replacement for the original Heath backplane. The H8 power hookup is seperate from the 24 pin connector so the wiring error does not affect that part of the board.

 

- Les

 

----- Original Message -----

From: Les Bird

To: se...@googlegroups.com

Sent: Wednesday, September 16, 2009 5:30 PM

Subject: [sebhc] Re: H8 Backplane/Motherboard

H8-BP (backplane/motherboard) prototypes check out. The attached pictures show a H8 computer powered using a 450 watt $30 ATX power supply. All that is required is to strap the voltage in/out of each board in the system (photo shows how I did it on the Z80 CPU card). The ATX power supply is a much better solution for powering the H8. First, it is a proven power supply. Second, they are cheap, powerful and plentiful. Third, when you turn it on the power is there and when you turn it off the power is off - there's no slow power up or waiting for parts to charge and when you turn it off you don't get the fade-out effect on the front panel like you do with the original power source. It's a nice clean on/off solution. And I won't even mention the weight difference (those H8 transformers are heavy)! Plus most of them have a built-in fan for cooling down the system (if you mount it inside the chassis) but without the hot regulators on the boards it's a much cooler running H8 system.

[Les Bird]

Update #2:

 

Finally got the final backplanes in and they work as expected. The final piece is here and ready to ship. For those who want a complete set of PCBs for building your own H-8 clone (or L-8 as Jack calls it) you can now order them from me. The cost for a complete set which includes the H8-FP front control panel, H8-BP backplane, H8-Z80-64 Rev 2 with GIDE, H8-4 Multi Serial Port card and H8-17 hard sector disk controller, will be $180 plus $5 for shipping.

 

It took a while to get all the pieces but I'm happy to say that my H-8 clone project is finally complete, that is except for the chassis of course.

 

I've attached the layout for the new backplane along with a slightly blurry photo of Terry Gulczynski's clone he built using a BUD chassis from Newark Electronics (see link below).

 

http://www.newark.com/bud-industries/ac-1429/ac-series-chassis/dp/06M4378

 

If you're interested in ordering a PCB set send me an e-mail and I'll invoice you for the total. I have enough H8-4's and H8-17's for 5 orders but more are on the way.

 

- Les

les...@bellsouth.net

 

[Les Bird]

To those who are interested:

 

I've put together a fairly detailed web page on constructing a Heathkit H-8 clone computer (the H8-2000 as I call it) using my PCBs. The link is below:

 

http://www.lesbird.com/sebhc/pcbs/H8-2000_Construction.html

 

This will be the standard guide to use for building up a system and includes plenty of photos with notes along with available disk storage options like the SVD and HSFE. One feature I designed into the new backplane is a plug for standby power. When using an ATX-type power supply and when the power supply is plugged in and turned on it has a +5V standby supply which is always on. This can be used to power internal devices such as an SVD so that it will retain it's contents even when the H-8 system is turned off. This is mentioned on the web page link above.

 

If you have any suggestions about stuff I need to add please let me know so I can update the page.

 

- Les

http://www.lesbird.com/sebhc

 

----- Original Message -----

From: Les Bird

To: se...@googlegroups.com

Sent: Monday, October 26, 2009 10:28 AM

Subject: [sebhc] Re: H8 Backplane/Motherboard

[Jack Rubin]

Love it! Would you be willing to recast it as a .pdf so that a clean paginated copy can be printed and kept with the system for reference?

 

Jack

[Les Bird]

Jack,

 

I ran the web link through an HTML to PDF converter and added a link to the PDF file to the home page (H8-2000 Construction Notes). I'm not sure how well it'll print out though because I had to do it as a single PDF page or else it would break up the images.

[Chris Elmquist]

Excellent work Les. Very impressive... and thanks for the plug on the HSFE
too ;-)

cje

--
Chris Elmquist

[Les Bird]

Thanks Chris, and no problem for the plug. The HSFE is an excellent
invention!

- Les