H8 supply and demand

[Glenn Roberts]

I can’t recall the last time there were four active eBay listings for H8 systems

334764632528
234766764412
175630301020
364165304722

The last one has an interesting wire wrapped interface board for a keyboard. Unfortunately the seller has listed the keyboard separately! (394488476371)

He’s also got a RAM board that could be worth fixing up (364165301500). I don’t see a brand marking on it…



Sent from my iPad

[smb...@gmail.com]

If that's the DRAM board with the D8202 on it, I may bid on that one -- it's basically the design I was trying to build, but could not get to work. I could learn something from it. I don't suppose anyone here already has one, or (better yet) has a schematic or documentation?

Scott

[glenn.f...@gmail.com]

It would be interesting to learn more about this board.  I don’t see any markings on it?? no manufacturer?  Odd…  let us know if you get it!

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[norberto.collado koyado.com]

Interesting board. First time seeing such board. 

Get Outlook for iOS

---

From: se...@googlegroups.com <se...@googlegroups.com> on behalf of glenn.f...@gmail.com <glenn.f...@gmail.com>
Sent: Wednesday, March 1, 2023 7:40:46 AM
To: se...@googlegroups.com <se...@googlegroups.com>
Subject: RE: [sebhc] Re: H8 supply and demand

 

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/007a01d94c54%2431145440%24933cfcc0%24%40gmail.com.

[Dick McCoy]

It appears to be the same board as in this listing :  https://www.ebay.com/itm/234766764412

Dick

[smb...@gmail.com]

Ummm, whose up for starting a business manufacturing H8-3 boards? 

https://www.ebay.com/itm/304815736593

[Mark Garlanger]

Looks like the auction also had an unbuilt Cleveland Codonics graphics board for the H19/H89. 

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/99daeaef-a9d4-4168-a740-954e76746dc0n%40googlegroups.com.

[glenn.f...@gmail.com]

What the ???!!!

 

I guess I moved out of northern VA a few years too early… This guy in Hamilton seems to have quite a trove of Heath stuff…

 

To so be clear this is a pristine and very nice looking NOGDS HA-8-3 board and documentation (but I don’t see the floppy disk with software?)  Those are unusual but they do come up on eBay from time to time, typically installed in an H8.  See clip from catalog 853 below. our fellow SEBHCer David Troendle was part of the NOGDS team that developed this board and the software.  (NOGDS = New Orleans General Data Services – catchy name 😊 ).

 

The rest of the lot is just a bunch of old Jim-Pak stuff and some spare ICs. Am I missing something?  Is that PCB something special?

 

$1,300 ?? seriously? 

 

I missed this in my eBay search.  What category was it posted in?

 

FYI we have cloned this board and we have the software and doc’s

https://koyado.com/heathkit/New-H8-Website/ha-8-3.html

 

I’ve had some fun writing new software for it and will post more about that … one of these days…

 

Recently Les discovered the long lost Graph-Pak II software and doc’s for this, plus we have some HUG games and one actually written by Les himself “back in the day”!  but all-in-all not much software was ever published in the Heath space for this board…  the TI9918 video chip and AY-3-8910 audio chip used on this board were used in a wide variety of computers and game consoles at the time.

 

• Glenn

 

 

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/99daeaef-a9d4-4168-a740-954e76746dc0n%40googlegroups.com.

[glenn.f...@gmail.com]

Ah!  Interesting.

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/CAAjkm79JZqbydwHGwZa%2Bfg2d-YxXjwgROo%2BE2ins%3DwSYO_umWw%40mail.gmail.com.

[Les Bird]

And speaking of the Graph-Pac II software library I sent the docs to Dave and he scanned and cleaned it up. Posted here:

https://github.com/sebhc/sebhc/wiki#micro-doc

I too was wondering how I missed that in my eBay searches.

Les

[smb...@gmail.com]

Sometimes I'll just do a global search for "Heathkit" to look for not only vintage computer stuff, but also trainers, robots, ham radio stuff, etc. That's probably how I found it.

I feel bad for the buyer, if he didn't know that he could simply build his own, or even pay someone to build one for him, for well less that $1300. Then again, maybe he wanted an original and the manuals, and maybe that H89 graphics board that was along with it has value that I'm not realizing.

There's probably a lot of folks out there who don't realize that Norberto, Les, and friends have reverse engineered many H8 boards, including some of the rare ones. I'm not sure how best to get the word out. There's clearly interest in H8s on eBay.

Scott

[Glenn Roberts]

We’ve kept somewhat of a low profile as there are some unscrupulous players out there. Most of what we have is easily discoverable with a Google search

I did write this piece a few years back…

Sent from my iPad

On Mar 2, 2023, at 11:05 PM, smb...@gmail.com <smb...@gmail.com> wrote:

Sometimes I'll just do a global search for "Heathkit" to look for not only vintage computer stuff, but also trainers, robots, ham radio stuff, etc. That's probably how I found it.

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/e820eaf1-d4eb-40b9-a8cd-181282a63845n%40googlegroups.com.

[Randy Eubanks]

What I found interesting is that to get to that final price, TWO bidders had to agree that the bundle was worth it. If those two bidders hadn't seen the listing, it would have sold for $126 (or less...)

BTW, I originally saw the listing by searching "Heathkit Computer"...

Randy

[smb...@gmail.com]

I think with eBay there's sometimes an irrational desire to win at any cost. I've seen new (and sometimes used) items go on eBay for more than you can just buy the thing on Amazon. 

The other interesting thing about this is that these guys started to go at it a little bit early, maybe an hour before close. Usually something like this happens in the last 5 seconds.

Scott

[Dave McGuire]

There's also often an irrational desire to believe things couldn't possibly be worth real money. Either way, "the market has spoken".

-Dave

On March 3, 2023 1:10:29 PM "smb...@gmail.com" <smb...@gmail.com> wrote:
> I think with eBay there's sometimes an irrational desire to win at any
> cost. I've seen new (and sometimes used) items go on eBay for more than you
> can just buy the thing on Amazon.
>
> The other interesting thing about this is that these guys started to go at
> it a little bit early, maybe an hour before close. Usually something like
> this happens in the last 5 seconds.
>
> Scott
>
> On Friday, 3 March 2023 at 10:00:40 UTC-8 randye...@yahoo.com wrote:
>
>> What I found interesting is that to get to that final price, TWO bidders
>> had to agree that the bundle was worth it. If those two bidders hadn't seen
>> the listing, it would have sold for $126 (or less...)
>>
>> BTW, I originally saw the listing by searching "Heathkit Computer"...
>>
>> Randy
>>
>> On Friday, March 3, 2023 at 2:03:36 AM UTC-8 glenn.f...@gmail.com wrote:
>>
>>> We’ve kept somewhat of a low profile as there are some unscrupulous
>>> players out there. Most of what we have is easily discoverable with a
>>> Google search
>>>
>>> I did write this piece a few years back…
>>> Heathkit H8 A Love H8 Relationship by Glenn Roberts

>>> <https://www.jameco.com/Jameco/workshop/MyStory/heathkit.html>
>>> jameco.com <https://www.jameco.com/Jameco/workshop/MyStory/heathkit.html>
>>> [image: favicon.ico]
>>> <https://www.jameco.com/Jameco/workshop/MyStory/heathkit.html>
>>> <https://www.jameco.com/Jameco/workshop/MyStory/heathkit.html>

>>>
>>>
>>> Sent from my iPad
>>>
>>> On Mar 2, 2023, at 11:05 PM, smb...@gmail.com <smb...@gmail.com> wrote:
>>>
>>> Sometimes I'll just do a global search for "Heathkit" to look for not
>>> only vintage computer stuff, but also trainers, robots, ham radio stuff,
>>> etc. That's probably how I found it.
>>>
>>>
>>> I feel bad for the buyer, if he didn't know that he could simply build
>>> his own, or even pay someone to build one for him, for well less that
>>> $1300. Then again, maybe he wanted an original and the manuals, and maybe
>>> that H89 graphics board that was along with it has value that I'm not
>>> realizing.
>>>
>>> There's probably a lot of folks out there who don't realize that
>>> Norberto, Les, and friends have reverse engineered many H8 boards,
>>> including some of the rare ones. I'm not sure how best to get the word out.
>>> There's clearly interest in H8s on eBay.
>>>
>>> Scott
>>> On Thursday, 2 March 2023 at 15:34:58 UTC-8 Les Bird wrote:
>>>
>>>> And speaking of the Graph-Pac II software library I sent the docs to
>>>> Dave and he scanned and cleaned it up. Posted here:
>>>> https://github.com/sebhc/sebhc/wiki#micro-doc
>>>>
>>>> I too was wondering how I missed that in my eBay searches.
>>>>
>>>> Les
>>>>
>>>>
>>>> On Thursday, March 2, 2023 at 4:26:13 PM UTC-7 Glenn Roberts wrote:
>>>>
>>>>> Ah! Interesting.
>>>>>
>>>>>
>>>>>

>>>>> *From:* se...@googlegroups.com <se...@googlegroups.com> *On Behalf Of *Mark
>>>>> Garlanger
>>>>> *Sent:* Thursday, March 02, 2023 6:10 PM
>>>>> *To:* se...@googlegroups.com
>>>>> *Subject:* Re: [sebhc] Re: H8 supply and demand

>>>>>
>>>>>
>>>>>
>>>>> Looks like the auction also had an unbuilt Cleveland Codonics graphics
>>>>> board for the H19/H89.
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> On Thu, Mar 2, 2023 at 4:49 PM smb...@gmail.com <smb...@gmail.com>
>>>>> wrote:
>>>>>
>>>>> Ummm, whose up for starting a business manufacturing H8-3 boards?
>>>>>
>>>>>
>>>>>
>>>>> https://www.ebay.com/itm/304815736593
>>>>>
>>>>> On Thursday, 2 March 2023 at 09:15:31 UTC-8 Dick McCoy wrote:
>>>>>
>>>>> It appears to be the same board as in this listing :
>>>>> https://www.ebay.com/itm/234766764412
>>>>>
>>>>>
>>>>>
>>>>> Dick
>>>>>
>>>>>
>>>>>
>>>>> On Wednesday, March 1, 2023 at 7:43:01 PM UTC-6 Norby wrote:
>>>>>
>>>>> Interesting board. First time seeing such board.
>>>>>
>>>>>
>>>>>

>>>>> Get Outlook for iOS <https://aka.ms/o0ukef>
>>>>> ------------------------------
>>>>>
>>>>> *From:* se...@googlegroups.com <se...@googlegroups.com> on behalf of
>>>>> glenn.f...@gmail.com <glenn.f...@gmail.com>
>>>>> *Sent:* Wednesday, March 1, 2023 7:40:46 AM
>>>>> *To:* se...@googlegroups.com <se...@googlegroups.com>
>>>>> *Subject:* RE: [sebhc] Re: H8 supply and demand

>>>>>
>>>>>
>>>>>
>>>>> It would be interesting to learn more about this board. I don’t see
>>>>> any markings on it?? no manufacturer? Odd… let us know if you get it!
>>>>>
>>>>>
>>>>>

>>>>> *From:* se...@googlegroups.com <se...@googlegroups.com> *On Behalf Of *
>>>>> smb...@gmail.com
>>>>> *Sent:* Wednesday, March 01, 2023 10:23 AM
>>>>> *To:* SEBHC <se...@googlegroups.com>
>>>>> *Subject:* [sebhc] Re: H8 supply and demand

>>>>> <https://groups.google.com/d/msgid/sebhc/0acae3da-77e1-4073-925c-569a97115b96n%40googlegroups.com?utm_medium=email&utm_source=footer>
>>>>> .

>>>>>
>>>>> --
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>>>>> an email to sebhc+un...@googlegroups.com.
>>>>>
>>>>> To view this discussion on the web visit

>>>>> https://groups.google.com/d/msgid/sebhc/007a01d94c54%2431145440%24933cfcc0%24%40gmail.com
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>>>>> .

>>>>>
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>>>>> https://groups.google.com/d/msgid/sebhc/99daeaef-a9d4-4168-a740-954e76746dc0n%40googlegroups.com
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>>>>> .

>>>>>
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>>>>> <https://groups.google.com/d/msgid/sebhc/CAAjkm79JZqbydwHGwZa%2Bfg2d-YxXjwgROo%2BE2ins%3DwSYO_umWw%40mail.gmail.com?utm_medium=email&utm_source=footer>
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--
Dave McGuire, AK4HZ
New Kensington, PA

[Randy E (OoMOR)]

Now let's see if they are actually paid for, or if they get relisted in a week or so.

[smb...@gmail.com]

Anybody here buy the one that went for ~ $342 a couple days ago from "oldpadlocks" ?

If so, I'm curious if he went through with the sale. I got a good deal on an S-100 board from him, but today it was refunded without explanation and there's been no communication from the seller.

Scott

[Les Bird]

I watched the last 2 minutes of that auction expecting it to quickly climb to close to a $1000 and was shocked that it went for only $342. Seems like a steal to me.

Les

[glenn.f...@gmail.com]

Well it shows the importance of presentation.  The other recent one went for almost $1,000 more, and wasn’t that different in spec’s, but has been cleaned and serviced and was advertised as in working condition, vs. “for parts or repair”.

 

If anyone here was the buyer on either of these we’d love to hear about your plans!

 

• Glenn

 

 

From: se...@googlegroups.com <se...@googlegroups.com> On Behalf Of Les Bird
Sent: Tuesday, March 7, 2023 8:53 AM
To: SEBHC <se...@googlegroups.com>

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/1f760ccd-9566-402e-965b-11aaaf34e831n%40googlegroups.com.

[smb...@gmail.com]

I'm shocked. I bit what I thought was a crazy high, unrealistic, nutty, irresponsible amount on https://www.ebay.com/itm/364165301500 and I came in second. There's someone out there (I wonder if it's the guy who bought that HA-8-3) who must be buying boards at any cost.

Ah well, it would have been nice to have used it to figure out what's wrong with my DRAM board, but not at $262.

Scott

[Troy S]

I am the buyer of the ~$342 H8. It arrived this afternoon and was only subject to minor jostling along the way. A couple cards came loose and a couple bus pins were slightly bent by some loose shielding in the case. I've seen, and had, much worse.

Like the photos on the listing indicate, it will need some cosmetic interventions. I plan to pull all boards and clean, inspect, and repair each as needed. As far as plans, get it running and have fun along the way.

Troy

[Glenn Roberts]

Congratulations Troy. We’d love to follow along, pictures are nice.  Looking forward to seeing it up and running. Another H8 saved!

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/a82f1464-1f50-40cf-899a-0f61270b49cdn%40googlegroups.com.

[smb...@gmail.com]

Nice! I think that'll make you a nice machine. Please do take pictures of the two RAM boards that are inside it.

I do wonder why the seller canceled my S-100 board that I bought from him, which closed (and was paid for) at approximately the same time you bought your H-8. He's not talkin' to me, so I suppose I'll never know.

Scott

[Troy S]

I'm sorry that your deal didn't go through. This H8 seems to have good bones. I'm looking forward to getting rid of the obligatory stale tobacco smell.

Here's some pictures of the boards:

Troy

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[Glenn Roberts]

Maybe just me but I can’t see the pictures…

Sent from my iPad

On Mar 9, 2023, at 8:18 PM, Troy S <troya...@gmail.com> wrote:



To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/CAEgE%3DmKRuvczXMtX4iYfK14qohycr5DfRGjAHN_aoQWLRvja6g%40mail.gmail.com.

[Troy S]

[Glenn Roberts]

Those 16 k Heath boards were great. I’ve still got the three from my original h8 and they’re running great. The Trionyx boards sometimes had issues.

Sent from my iPad

On Mar 9, 2023, at 8:23 PM, Troy S <troya...@gmail.com> wrote:



To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/c0305df1-9d24-40b2-b73a-ce3dca950930n%40googlegroups.com.

<IMG_6668.jpg>

<IMG_6669.jpg>

[smb...@gmail.com]

Nice. That looks like the Trionyx DRAM board. Not the one I'm searching for, but it is perhaps the one that has the schematics checked in to the sebhc github. The SRAM board is a nice one too. I might try to clone the SRAM just for the hell of it, the SRAM board is simple enough.

Maybe try an ozone generator for the tobacco smell? I have one that I use to get the mold out of my jeep, and more than once I've thought about tossing some vintage electronics in there with it.

Scott

[Dave McGuire]

On 3/9/23 20:33, smb...@gmail.com wrote:
> Maybe try an ozone generator for the tobacco smell? I have one that I
> use to get the mold out of my jeep, and more than once I've thought
> about tossing some vintage electronics in there with it.

I'm reminded of the time when a friend got one of those glorious,
indestructible Steelcase desks from the 1950s from another friend, whose
wife smoked like a chimney.

He had it in the back of his pickup truck, and ended up just driving
it through a car wash. He said it worked!

Not that I'd advocate that plan for an H8, but it's a funny memory.

-Dave

[steve shumaker]

Troy

I have what seems to be a complete documentation set for for the Trionyx M-H8 (although NOT the /A version).   This includes user manual, parts list, a changes/mods document, schematic and even a timing diagram.  I think all of this is on SEBHC page but since you have a board you're welcome to the docs for postage if you want them.  I have no current use and only accidentally acquired them recently as part of an auction lot.

Steve

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/c0305df1-9d24-40b2-b73a-ce3dca950930n%40googlegroups.com.

[smb...@gmail.com]

Seller says the $2500 eBay H8 went for $2000. That's quite a range of prices, one going for $342 (lowest I've seen on eBay in recent history) last week, and one going for $2K this week.

Did anyone here buy it? If so, it's yet another source for that DRAM board I'm seeking to reverse engineer.

Scott

[Les Bird]

So let me get this straight. An H8 with an original 8080 CPU card and a single RAM board with no serial interface card or software or manuals sold for $2K?

Wow.

[Glenn Roberts]

Scott: what’s your source for the $2k number? If it’s from the seller not sure we can trust that info. 

Sent from my iPad

On Mar 12, 2023, at 6:10 PM, Les Bird <lesb...@gmail.com> wrote:

So let me get this straight. An H8 with an original 8080 CPU card and a single RAM board with no serial interface card or software or manuals sold for $2K?

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/ba5c5e87-7f8c-40f4-9aae-65e320684132n%40googlegroups.com.

[smb...@gmail.com]

He posted on vcf. I sensed a dig at me in his comment, since I previously told him it was a bare bones h8 not worth his asking price. I believe 3 months ago I offered around 300 to 400 bucks for it. Back before I bought yours.

He does have a second one with manuals, drives, etc that he posted on vcf last year

Sent from my iPhone

On Mar 12, 2023, at 3:16 PM, Glenn Roberts <glenn.f...@gmail.com> wrote:

Scott: what’s your source for the $2k number? If it’s from the seller not sure we can trust that info. 

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/DE70A371-6DA9-497A-B7C9-74B31F7A6AEC%40gmail.com.

[smb...@gmail.com]

Next up, a listing full of unbuilt boards: https://www.ebay.com/itm/185811931414

I'd say it's dramatically overpriced, but then again: 1) unbuilt heathkits of any kind go for a lot of money, and 2) I've proven my powers of estimation to be unreliable lately.

Scott

[glenn.f...@gmail.com]

So I guess I can sleep tonight; this sold.  I really didn’t think it would last the night (though with a “make offer” listing do we actually know what the buyer paid?)

 

I seriously considered at least making an offer on this. The market has spoken, and presumably this sold for somewhere near the asking price. Still it would have been an exciting auction to watch if it hadn’t had a “buy now”. Given what we’ve seen some things go for lately who knows what this would have fetched in open bidding!?  Anyone want to fess up to being the buyer?

 

I don’t think the seller even mentioned the two Mullen extender board kits?  And all four of the 4K RAM boards had the H-8-3 4K RAM expansion.  It really is a remarkable collection…

 

But what would I have done with it?  sell the pieces I guess.  I couldn’t bear to actually build these, though some YouTubers with enough eyeballs could perhaps monetize their “build” video?

 

Presumably these will show up as individual listings soon so watch  your eBay search results...!

 

• Glenn

 

 

From: se...@googlegroups.com <se...@googlegroups.com> On Behalf Of smb...@gmail.com
Sent: Sunday, March 12, 2023 7:19 PM
To: SEBHC <se...@googlegroups.com>
Subject: Re: [sebhc] Re: H8 supply and demand

 

Next up, a listing full of unbuilt boards: https://www.ebay.com/itm/185811931414

Troy

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/18cb641f-19be-4cfd-8768-14fa0de6b74en%40googlegroups.com.

[Willis Blackburn]

Hey folks. I'm the buyer of the $2,000 H8 that you're talking about it.

The seller wouldn't go below $2,000. I might have overpaid a little, but I've been trying to get one since I saw the exhibit at the 2021 VCF, lost a few auctions, got tired of waiting.

What convinced me to get it was the fact that it worked, didn't have any broken lights or keys, and... the 64K DRAM board.

Which is why I'm here, to ask if anyone knows anything about this board! I ordered 24 more MK4116 chips (and sockets) to actually bring it up to 64K, but I have no idea how to set the DIP switches, other than to copy the settings from the board in the other eBay auction that has all 32 chips installed.

I asked the seller of the other eBay auction about the board, he didn't know, but says that he has another one, if anyone wants to try to convince him to sell it. He also said he would ask the buyer if they knew anything about it.

I posted about it on Retrocomputing StackExchange too: https://retrocomputing.stackexchange.com/questions/26684/whats-this-mysterious-dynamic-ram-board-in-my-heathkit-h8

To Scott, the person who posted the message saying he was trying to build a board similar to this, I can send you detailed photos, if that would help, or you can just come look at the thing, if you're nearby. I'll have to reverse engineer it a bit in order to understand how to set the DIP switches anyway, assuming I can't find a manual.

Willis

[smb...@gmail.com]

Fantastic! I'm so glad we know somebody who has one of these boards. We've talked about it here, as well as in my other thread on the DRAM board I'm designing. As far as I know, we don't know who made the board, nor do we have any documentation. There is a DRAM board that we do have documentation for, made by Trionyx, but it is clearly not this board (it does not use the D8203 and instead implements timing manually).

I would love to get as many high resolution pictures as you can provide, and I'd be happy to share what I can learn from the pictures. Unfortunately, there's often traces on the top of the board that are not visible because they run underneath ICs and there's not much you can do about that, other than taking a multimeter and trying to trace signals. It might not be possible to generate a full schematic, but I think folks here (including myself) ought to be able to get an idea of what the various dip switches and jumpers do.

I don't want to speculate too much without taking a closer look, but given that it has an 8-position dip switch, it's possible that the board implements org0 support on it. The 4-position dip switch could be to configure the starting address (in a non-org0 configuration). Those are just some guesses.

As far as the $2000, as long as it's the machine you want for the price you wanted to pay, that's what matters most. These things are rare, so sometimes you gotta grab what you can.

Scott

[glenn.f...@gmail.com]

Really odd that there are no commercial markings on that RAM board.  I tried looking through a few old Sextants to see if I could spot an ad but no luck.

 

Congratulations on  your new H8 Willis. Hope you can post more here about what you learn about the system and any restoration or updates that you do!

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/f3d1fe4b-c79e-4dba-ab69-7acb595cfc3an%40googlegroups.com.

[norberto.collado koyado.com]

We made some boards for the H8 during the time the IBM PC market was ramping up. We sold maybe 200 as the H8 was market was dead at that time. Perhaps this board went thru the same process as we did. Never got into sextant either.

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Sent: Wednesday, March 22, 2023 5:37:28 PM
To: se...@googlegroups.com <se...@googlegroups.com>
Subject: RE: [sebhc] Re: H8 supply and demand

 

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/00de01d95d1f%24a5f95310%24f1ebf930%24%40gmail.com.

[smb...@gmail.com]

My latest video paid off -- I briefly showed the unknown DRAM board, and I heard back from the person who bought the DRAM board from the eBay auction. So that puts us into contact with two people who own the unknown/unbranded DRAM boards. There's still one more floating around out there somewhere.

Unfortunately, even with his pictures, I'm not much closer do deciphering the thing. There's at least a half-dozen traces that go underneath ICs that I lose track of, and those tend to be the important ones, such as the wait logic. Maybe once we have Willis's pictures there will be something more I'm able to see. Otherwise I might have to try to talk someone into poking around with a continuity tester to resolve the lost traces.

Scott

[norberto.collado koyado.com]

😳 It took me two years and $80.00 to find the HDOS version of QuikStor. Hopefully, you will get it going soon.

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Sent: Monday, March 27, 2023 11:26:08 PM

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[Willis Blackburn]

Here are some more detailed photos of the DRAM board:

https://drive.google.com/drive/folders/1wrBhM6zt8bEfuPPy1T1bhkMCzRbu-Hql?usp=sharing

I took the chips out for one of photos so you can get an idea of where the traces go. Unfortunately the 8202A uses a socket that isn't open so it's hard to tell what's going on behind it. Let me know if you want me to check anything for continuity.

W

[smb...@gmail.com]

Thanks Willis.

Very interesting. The other board has a hollow socket under the D8202, which helps.

Where I ran into most of my trouble tracing are the 74S03, 74LS14, and 74LS74 to the right of the D8202.

Are you handy with a multimeter? I could use verification of the following connections:

U5 74LS74:

  pin 3 - maybe M1 (6th pin down from top of the lower edge card connector)

  pin 5 - maybe pin 13 on the U7 74S08

  pin 9 - maybe pin 1 on the U14 74LS240 next to the 8-pin dipswitch

  pin 10 - maybe pin 5 on the U10 74LS14

  pin 11 - maybe RESET (5th pin up from bottom of upper edge card connector) or M1 (6th pin down from top of lower edge card connector)

  pin 13 - maybe RESET (5th pin up from bottom of upper edge card connector) or M1 (6th pin down from top of lower edge card connector)

U6 74LS32

  pin 1 - somewhere near 74LS14 (I can try to narrow this down later)

  pin 2 - somehwere near D8202 (I can try to narrow this down later)

  pin 11 - maybe pin 33 of D8202

U10 74LS14

  pin 1 - maybe IOW (4th pin down from top of lower edge card connector)

  pin 11 - maybe D8202 pin 33

  pin 13 - maybe D8202 pin 29

U11 74S03

  pin 5 - maybe D8202 pin 30

  pin 6 - maybe RDYIN (5th pin down from bottom edge card connector)

Also sending up a picture where I've put IC numbers (U5, U6, ...) on the chips when I started working on the netlist.

Scott

[smb...@gmail.com]

Also, picture from the other owner with the 8202 removed.

Scott

[Willis Blackburn]

Check the Google Drive folder again. The picture w/o the sockets was blurry so I retook it.

[Willis Blackburn]

U5

pin 3: Correct (your picture is a little angled, so it's not so clear, but it's pretty obvious in my photo)

pin 5: Looks like pin 10 on U7

pin 9: Correct, pin 1 on U14

pin 10: Correct, pin 5 on U10

pin 11: Here my board apparently differs from yours. On mine, pin 11 travels to what looks like a via right below the left end of the orange wire in your diagram, then there's a jumper wire that connects it to the left side of the orange wire is on your board. It winds up on pin 4 on U6

pin 13: Correct

U6

pin 1: Connects to pin 13 on the same chip. You can see clearly in my back photo.

pin 2: Pin 32 on 8202

pin 11: Pin 11 on U10

Gotta run an errand, will follow up with the others.

[smb...@gmail.com]

Thanks Willis,

You mentioned that U5-11 was correct -- was it to RESET or to M1 ?

Also note that some of them may connect to more than one place. U6 has multiple examples. Here's my breakdown of U6:

1 (A1) U6-13, MAYBE-near-U10
2 (B1) R1, U11-3, MAYBE-near-U13
3 (Y1)
4 (A2) Jumper to JP1
5 (B2) U10-2 (Y1)
6
8
9
10
11 (Y4) U10-11 (A5), MAYBE-U13-33 (PCS)
12 (A4) U7-3 (Y1), JP3-2
13 (B4) U6-1
14

Tonight I'll upload my full netlist-in-progress to github.

Scott

[smb...@gmail.com]

Willis,

My netlist-in-progress is in https://github.com/sbelectronics/h8/blob/master/h8-dram/ebay/netlist.txt. Anything with "MAYBE" in it is unverified (I haven't updated the verifications you posted above yet).

Scott

[Willis Blackburn]

U5 pin 13 was RESET.

U10

pin 1: Connects to 4th pin from top of the bottom bus connector ("I/O W?")

pin 11: U6 pin 11

pin 13: Appears not to connect to anything; see the back photo

U11

pin 5: 8202 pin 30

pin 6: Correct, connects to RDYIN

[Willis Blackburn]

Some of your "maybes:"

U1

pin 12: Connects to U9 pin 1 and also U13 pin 1

U3

pin 1: Confirmed U13 pin 38

pin 4: Confirmed U13 pin 39

pin 14: Confirmed U8 pin 2

U4

pin 6: Connects to U1 pin 20

U7

pin 1: Connects to U13 pin 32 (not 33)

pin 2: Connects to U13 pin 31 (no sign of any connection to U5)

pin 12: Connects to U1 pin 5 (no connection to U11)

pin 13: Connects to U1 pin 3

Will check more later.

[smb...@gmail.com]

Thanks Willis,

Can you config U10 pin 13 ? I saw that one as likely on the top side of the board.

Scott

[smb...@gmail.com]

The more I work on this, the more confused I get. The pins I need to confirm the most are:

29 (XACK) MAYBE-U10-13
30 (SACK) MAYBE-U11-5
31 (WR) MAYBE-U11-11, MAYBE-U7-2(willis)
32 (RD) MAYBE-U6-2, MAYBE-U11-3, MAYBE-U7-1(willis)
33 (PCS) MAYBE-U10-11, MAYBE-U6-11

Have you been able to continuity check all of those possibilities Willis? I added the two that you found on U7. U7 is kind of hard to see in my pictures.

I also need to nail down U6-1/U6-13. These are both inputs, so they must also connect to another place. Looking at your top picture, without the ICs, I believe I can see U6-1 head over to U10-12.

Scott

[Scott Baker]

I had another interesting insight about this board. It's wired to IOW, but not IOR. The 8-bit dipswitch is not an org0 port, as you can't actually read it. My best guess so far is that it allows banks to be turned on/off individually (similar to the SEBHC 64K RAM board). However, you might also be able to turn banks on/off under software control by writing to some port.

Scott

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/f202e8af-41b7-41aa-8bb8-fc4cde9e1cacn%40googlegroups.com.

[smb...@gmail.com]

It just dawned on me -- the reason why there's an IO port that lets you turn sections on/off in 8K increments is so you can install more than one DRAM board, and bank switch between them. It has a rudimentary memory mapper. The 2x4 jumper blocks allow the port to be selected on a per-board basis. The dip switch is so you can specify an initial configuration. if you have two boards installed, start with all the RAM turned off in one, and turned on in the other... or maybe you want to start with 32K on one board and 32K on the other. Maybe a split configuration like that would better distribute the refresh overhead.

It's a complicated solution. There's at least 7 ICs used for this feature.

Scott

[Willis Blackburn]

I can let you know about the connections after I get home today.

I think your idea about the purpose of the 8-switch DIP is spot on. The 64K board in the auction photo has switch 8 on and the rest off. It seems a little backward, but if we assume that "on" really means "disabled," and the switch represents 8K banks from switch 8 to switch 1 (in other words, switch 8 is 0-8K, switch 7 is 8-16K, etc.), then the 64K board is showing that 0-8K is disabled (to make room for the built-in ROM and RAM) and the rest enabled. Meanwhile my 16K board shows switches 6 and 7 off and the rest on. That means 16K enabled from 8-24K and the rest disabled, which is exactly how my machine is set up.

If that's really how this works then we totally have to make a few more of these and see if the bank switching actually works. :-)

The mapping of the address range to the actual chips on the board must be a little weird though. Maybe the first (top) 16K bank on the board gets addresses 8-24K, etc., through to the last (bottom) bank, which gets 56-64K and also 0-8K.

Once you get a better idea of how everything works, hopefully we'll understand why the boards have some differences. There are two 2x4 blocks of 8 holes that look like they may have been been intended to accommodate some jumper pins. Yours has a wire connected to one that mine doesn't.

W

[smb...@gmail.com]

The 4-dip-switch on the right is hooked up to a 4-bit adder. My assumption is that it can be used to offset the starting address of the board. I have this partially noted in the netlist, but haven't taken a detailed look yet. Should check if this 4-switch is set the same way on both boards that we have pictures of.

My assumption is the two 2x4 jumper blocks are to set the address for the write-only IO port. Both of these jumper blocks are connected to 74LS138 3-8 decoders, presumably 3 bits of address specified to each jumper block. That only gets us to 6 bits of port address, maybe the setting of two of the bits is assumed. That your board is lacking one of the jumper wires, perhaps that means the IO port is disabled on that board. Maybe you only enable the IO port if you intend to use multiple boards.

Hopefully get a clearer picture on everything over the weekend.

Scott

[Willis Blackburn]

I can test your theories about the operation of the DIP switches by putting the board back in the machine and, assuming it still works after I took out and replaced all the chips, testing different settings. It's straightforward to determine how much RAM is in the system and where it lives from the front panel. I could also try out your theory about writing to the port to turn the banks on and off if you can work out what the port number is.

I ordered parts to upgrade my board to 64K so that will open up some more testing possibilities. All the little filter caps on the board are from 1982 but the exact same part number is still available from Digi-Key.

W

[norberto.collado koyado.com]

Hello Willis,

 

Any opportunities to ship your board to Scott, so that we can duplicate such board at a smaller scale?  I can share with you one of my memory boards fully assembled (512KB) or I can send you a Z80 V3 board fully operational with 64KB of RAM to keep you busy with such system until Scott is done with his new re-design… 😊

 

Thanks for all your support,

Norberto

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/dbc280de-d307-426a-a063-0b63304697e2n%40googlegroups.com.

[smb...@gmail.com]

Norberto,

While I wouldn't mind having one of these in my possession, I do think we're making really good progress reverse engineering it over email. Once I have every "MAYBE" in the netlist checked and double-checked by Willis, I'll take a stab at drawing a schematic of the wait logic this weekend. Once that's done I should be able to get my existing prototype working. I already have a preliminary understanding of how the wait logic works. As usual, once you understand the "how" and the "why" of the design (things like the bank switching), it's easy to reimplement that with newer logic. One PLD can replace a half-dozen or more of the logic chips, and the board becomes pretty simple to understand.

An open question is whether or not this board works on Z80, or if it's 8080-only. 

Scott

[Willis Blackburn]

I can provide the board. I can also reverse-engineer it myself or produce a PCB from Scott's netlist. My understanding is that Scott is more interested in producing his own design and is looking for a working example of something similar, rather than trying to clone this exact board.

How far do you want to go in replacing the logic chips with programmable logic devices? I think the entire board, memory and all, could be reproduced in an FPGA, but it wouldn't be very interesting. Are you limiting yourself to stuff that would have been available in late 70s/early 80s? 

W

[smb...@gmail.com]

I think simple PLDs like GAL16V8 or GAL22V10 are fair game to simplify a design. My Convergent Miniframe, circa 1982, is full of GAL22V10. One of the advantages is that a screwup in logic is much more easily repaired in the PLD than it is with the soldering iron. A few times I've had a board shipped before I even designed the logic because I knew whatever I needed would fit in the PLD. PLDs are also a great way to do address decoding, as you can easily reprogram a PLD if you want to change an IO port.

My primary interest was in building my own board, but I also think it would be nice to reverse engineer a schematic from this one, and even to produce gerbers and build a few of the things for our own use. I love the look of a computer populated with rows and rows of 4116s or 4164s. The way I look at it, folks like us here in this channel are the only ones preserving some of this history. A working design that anyone can send off to jlcpcb and have fabbed is a great way to prove the history is sufficiently well documented. :)

Scott

[norberto.collado koyado.com]

I know some boards required a jumper to select 8080A or Z80 mode. A great question… 

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From: se...@googlegroups.com <se...@googlegroups.com> on behalf of smb...@gmail.com <smb...@gmail.com>

Sent: Wednesday, March 29, 2023 2:59:20 PM

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/2843a6de-b9bc-477f-b734-b77a40164993n%40googlegroups.com.

[Willis Blackburn]

U13-29 -> U17-11 (nothing on U10)

U13-30 -> U11-5

U13-31 -> U11-1, U7-2 (confirmed these two are connected independent of U13)

U13-32 -> U6-2, U7-1, U11-3 (ditto)

U13-33 -> U6-1 (not 11), U6-13,  U12-3, U12-6, U12-8, U12-11, U18-3, U18-6, U18-8, U18-11 (nothing on U10)

Hopefully this sheds some light on the U6-1/U6-13 situation. You read this right, these both connect to pin 33 and also to pins 3, 6, 8, and 11 on both U12 and U18. U12 and U18 are both quad tristate buffers, and pins 3, 6, 8, and 11 are the outputs of the four buffers. From your netlist it looks like the control pins for the buffers all connect to U8. So U8 is some kind of selector that is choosing which upstream source gets to control the net that includes U13-33, U6-1, and U6-13.

W

[smb...@gmail.com]

Thanks Willis, excellent work on the U13 situation. :)

U12 and U18 implement the logic for the bank switching. Attached is a very crude block diagram (I'll do a real schematic some day in the future) of how it fits together. The Dipswitch or the latch sends 8 bits to the LS125s, then the top three address lines go to a 3-8 decoder and will select one of the buffers in one of the LS125. This then generates the chip select for the DRAM, depending on which dipswitch (or latch bit) was set.

[smb...@gmail.com]

Willis, I've updated the netlist to confirm everything you've sent me. I've added a couple more maybes. Could you verify the remaining maybes?

Also, I'm attaching a picture. Could you verify the following

* White capacitor -- read values/markings

* Blue resistor lead -- see if it goes to U13-28

* Yellow resistor lead -- see if it goes to U10-9

Thanks,

Scott

[smb...@gmail.com]

Oh, and I might have those wrong... Check

* yellow resistor - U11-8

Scott

[Willis Blackburn]

White cap says XF5 270M 1KV.

Blue: goes to U13-7 (not 8)

Yellow: goes to U11-8

[smb...@gmail.com]

Thanks. Could you double-check blue resistor? U13-7 doesn't make sense to me -- should be either U13-27 or U13-28.

Thanks,

Scott

[Willis Blackburn]

It's entirely possible I counted the pins on the 21-40 side from 1 and found it connected to number 7 and then wrote it down as 7 not 27. If 27 makes sense then go with that. I'll check again when I get home.

[Tom Wilson]

Well that was a day "wasted" looking for an ad for this board.
You would think it had to be advertised somewhere for three
of them to show up on Ebay.

Tom

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[norberto.collado koyado.com]

We did announce on the Sextant Magazine. Perhaps, they did the same.

 

Norberto

 

From: se...@googlegroups.com <se...@googlegroups.com> on behalf of Tom Wilson <tomlan...@gmail.com>
Date: Thursday, March 30, 2023 at 8:54 AM
To: se...@googlegroups.com <se...@googlegroups.com>
Subject: Re: [sebhc] Re: H8 supply and demand

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/0c1b21b2-fae4-cca6-4e5f-2415cd4fd771%40gmail.com.

[Willis Blackburn]

I was going to suggest looking for an article rather than an advertisement. Given the lack of any commercial markings, vs. how easy it would have been to include them, I'm thinking it might have been someone's side project rather than a for-profit product. All the date codes on mine say 1982. Was there a big market for 64K memory upgrades for the H8 in 1982?

[Tom Wilson]

I did look in articles and classifieds.

You don't see much for the H8 after
Heath ran out of them. (FCC)

A couple companies used the
D8202,3 in  S-100 boards

Tom

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/7da61b58-7e8d-4df3-899f-efc77d2b6e28n%40googlegroups.com.

[Tom Wilson]

That was a good price on the memory board.

One of the S-100 boards was "Jaws"
maybe some ideas can be found in this design.

Tom

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/SN6PR01MB3855B09C1517D956512D8C95F78E9%40SN6PR01MB3855.prod.exchangelabs.com.

[Peter Higgins]

Back in the day I was one of the unfortunates who purchased the S100 "JAWS" DRAM board sold by Netronics. I was never able to get it working reliably with my S100 8080 CPU board, and I subsequently found most others had the same experience. I suspect Netronics designed and tested it to work with their "Explorer 85" 8085-based S100 SBC, and took advantage of the extended write strobe timing provided by the 8085. The JAWS board also made use of several 8080 status signals that are available on the S100 bus, but not the H8 bus.

[smb...@gmail.com]

Attached is a picture of what I believe the wait-state and write timing logic to be. Connections not related to these circuits left off (for example, CS connects to a half-dozen other places).

Unfortunately, I tried it tonight and it didn't work. So either 1) I have something incorrectly implemented, or 2) the netlist has a mistake in one of these nets.

Scott

[Willis Blackburn]

Crystal is 18.432MHz.

And yes, blue resistor does go to U13-27.

[smb...@gmail.com]

Hmm, I'm stumped at the moment. I believe I've faithfully reproduced the schematic I posted above for the wait state and the write timing.

1) The board seems to read fine.

2) 50% of the time when I do a write, the H8 will lock up. It's locking up because the DRAM controller is holding the CPU permanently in wait. /SACK goes down, but /SACK never comes back up again.

3) The /SACK and /XACK timing is not what I expected. Datasheet leads me to believe /SACK should precede /XACK unless the board is busy in a refresh when the memory operation occurs. What I observe is that /SACK never precedes /XACK. This suggests it's always in a refresh cycle when a memory op occurs, and that seems suspicious.

May give it some more thinking this weekend, but it also might be time for the logic analyzer. There's just only so much that can be done with a 4-channel scope.

Scott

[norberto.collado koyado.com]

Yes, time for a logic analyzer. It helps during such difficult times.

 

From: se...@googlegroups.com <se...@googlegroups.com> On Behalf Of smb...@gmail.com

Sent: Friday, March 31, 2023 1:02 PM
To: SEBHC <se...@googlegroups.com>
Subject: Re: [sebhc] Re: H8 supply and demand

 

Hmm, I'm stumped at the moment. I believe I've faithfully reproduced the schematic I posted above for the wait state and the write timing.

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[smb...@gmail.com]

Willis,

Could you track down U8-6? I think it might go to +5V, but I'm not sure.

Scott

[smb...@gmail.com]

Willis,

If you could double-check all of these that would be great. Note that I have left off some connections to these pins that are not relevant, so just check the ones here and beware some pins could connect to multiple places. I'm only looking at what's necessary for the wait state generation. If all of these verify, then I'll  conclude that my D8203 has an undocumented difference from the D8202 used in your board, and it's not possible to reproduce your board's wait state design using the D8203.

U6-12: U7-3

U6-13: U13-33

U7-1: U13-32

U7-2: U13-31

U8-6: +5V

U10-11: U6-11

U11-1: MR (card edge top conn, 4th up from bottom)

U11-2: MR (card edge)

U11-3: U13-32

U11-4: U10-10

U11-5: U13-30

U11-6: RDY (edge card bottom conn, 5th down from top)

U11-11: U13-31

U11-12: MW (card edge bottom conn, 2nd down from top)

U11-13: MW (card edge)

Thanks,

Scott

[Willis Blackburn]

I can check, am away for the weekend though, will be back tomorrow night.

[Scott Baker]

Thanks Willis.

I had a bit of success today, realizing I had the polarity of !SACK backward in my reverse-engineered wait circuit. Now the board is working most of the time.

"most" unfortunately isn't good enough. But it's closer.

Scott

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/2845d51a-a0da-4b66-8e5e-b1e198004a66n%40googlegroups.com.

[norberto.collado koyado.com]

One step at a time. 😊

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/CA%2B8qVMOow0Sk8vdW4070gaDiD8LStoOdKu_wqU0tcgSCtYZq-w%40mail.gmail.com.

[smb...@gmail.com]

Handful of boards up on ebay tonight from jackrubin, ranging from the mundane to the interesting.

No weird DRAM boards though.

[Glenn Roberts]

Indeed. Looks like he’s paring down some of the best of his H8 collection. You don’t see the NOGDS boards very often. Jack assembled the original set of “Les Bird” boards for Bill Loguidice (I think Bill is mostly a software guy) back before I bought Bill’s Heathkit collection. They became my “Rusty” system, which was near the start of my “later-in-life” renewed interest in the H8 about 10 years ago:

https://photos.app.goo.gl/gUTwssYczRJxecfn2

Sent from my iPad

On Apr 3, 2023, at 1:50 AM, smb...@gmail.com <smb...@gmail.com> wrote:

Handful of boards up on ebay tonight from jackrubin, ranging from the mundane to the interesting.

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/9b0db5a2-070a-485a-87d5-03ac5c314625n%40googlegroups.com.

[Mark Garlanger]

Jack was the original admin for the SEBHC mail list, both before we were using google (here the archive of that list: https://sebhcmaillist.heathkit.garlanger.com/sebhc/ ) and when we moved over to the google group.

Mark

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/9b0db5a2-070a-485a-87d5-03ac5c314625n%40googlegroups.com.

[glenn.f...@gmail.com]

Interesting to look back at those posts.. from as early as 19 years ago!!

 

Here’s Jack’s welcome post

https://sebhcmaillist.heathkit.garlanger.com/sebhc/2004-March/000001.html

 

much has changed since then, but much hasn’t.  sadly we’ve lost some members, and others have moved on to other things. When Ron West “retired” from the hobby he sold me his Z80-based H8/H19/H17 setup.

 

I see a few posts from me back in ’07 lamenting that my H17 disks were 20 years old. Now make that more like 40!

 

Glad you kept these Mark. Thanks

 

• Glenn

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[smb...@gmail.com]

Jack sold off a lot of his S-100 boards on eBay late last year. The S-100 semidisk board that I posted early came from one of Jack's auctions (the only one of them that I won).

On the topic of memory boards, I have confirmation from the other owner (David) of the H8 DRAM board that the DRAM board works properly in a Z80 clocked at 3.08 MHz. Was 3.08 MHz clock popular on Z80 boards?

Scott

[Willis Blackburn]

Scott, all of these are correct.

U6-12: U7-3: OK

U6-13: U13-33: OK

U7-1: U13-32: OK

U7-2: U13-31: OK

U8-6: +5V: OK

U10-11: U6-11: OK

U11-1: MR (card edge top conn, 4th up from bottom): OK

U11-2: MR (card edge): OK 

U11-3: U13-32: OK

U11-4: U10-10: OK

U11-5: U13-30: OK

U11-6: RDY (edge card bottom conn, 5th down from top): OK

U11-11: U13-31: OK

U11-12: MW (card edge bottom conn, 2nd down from top): OK

U11-13: MW (card edge): OK

[smb...@gmail.com]

It's not an H8, but since this is the thread where eBay listings have been talked about lately, this did pop up on my radar this morning:

https://www.ebay.com/itm/314546909031, 8 boxes of SS/DD diskettes, potentially hard-sectored. Not sure if this is the right things for an H17 or not, but if it is, perhaps somebody wants to stock up.

scott

[Glenn Roberts]

Who used 16-Hard Sector disks? Northstar? I suppose if you were ambitious you could modify the H17 ROM timings to use these… (like seriously ambitious…) I presume sectors were 128 bytes?

Sent from my iPad

On Apr 22, 2023, at 3:07 PM, smb...@gmail.com <smb...@gmail.com> wrote:

It's not an H8, but since this is the thread where eBay listings have been talked about lately, this did pop up on my radar this morning:

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/aaaa8b98-2f53-4af9-818c-bff62093cb88n%40googlegroups.com.

[Mark Garlanger]

It would be a lot more modifications than just the timings. The sector size on these would only be 128 bytes. Would take a lot to update cp/m and hdos to work with that.

Mark

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/8C2D3222-867B-4C66-8CD3-52E04A08BE5F%40gmail.com.

[Douglas Miller]

I'm trying to imagine how someone put 17 holes around a 5-1/4 diskette hub... without cutting the whole thing out... seems like the sector holes would be wider than the space between!

I'd heard of 16-sector 8" diskettes... never knew there were 5-1/4 ones...

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[Steven Feinsmith]

Unfortunately, it was NOT hard-sectored diskettes. You need SSSD, not SSDD. It was grossly misleading by the eBay seller, who knows nothing about it. The actual hard sectored diskettes have an index hole for every sector boundary; if the disk has ten (10) sectors, there are ten index holes plus usually one additional hole in a half-sector arrangement to mark the starting sector for each revolution. The soft-sectored diskettes have ONLY one hole marking the starting sector for each revolution.

I can see many people who put effort into searching for hard-sectored 5.25" SSSD floppy diskettes. Unfortunately, nowadays, there are NONE left in the market. I spoke with two manufacturers who made hard-sectored diskettes in the past. They destroyed equipment that produced the diskettes many years ago because they thought there were no longer in demand. One of them said they regretted removing the equipment and that building the equipment would be tremendously expensive.

Any floppy drives and diskettes were no longer worth it at all. Let me warn you, one of my friends bought a 5.25" TEAC for $150.00 through eBay a few years ago. He struggled to make it work but has yet to be successful. He asked me to double-check, so I checked and found hardware failure and not repairable because of a lack of replacement parts available. The seller refused to take it back and refund the money regardless; he said the unit was working conditions. I had to help him to get through legal procedures and win the case against eBay and the seller.

I would suggest that you and others forget about the floppy drive system. It is better to use a compact flash or similar by Norby. The good old days fade away very rapidly. The only good part of having the floppy drive device(s) is that it is like a museum display.

Steven

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[Douglas Miller]

SSDD would work just fine on the H17, but the 16-sector will not. The SSDD only indicates how the diskettes were verified. All DD-tested diskettes will work just fine in SD. The standard H17 was single-sided originally. We used to use SS diskettes in DS drives/applications, but one was taking a risk that the second side was inferior. Really depends on when the diskettes were manufactured as to the chances of getting a usable second side. Hard to say whether these diskettes were rejects from DS testing, or just not tested DS.

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/CAGJMgmU%2BGuyoiBDobHCzL7zvnYyR%2BvJh23EE148Qj9574WpgTg%40mail.gmail.com.

[William Sudbrink]

Northstar used 10 sector.  Vector Graphics used 16 sector.

 

Bill S.

 

From: se...@googlegroups.com [mailto:se...@googlegroups.com] On Behalf Of Glenn Roberts
Sent: Saturday, April 22, 2023 3:14 PM
To: se...@googlegroups.com
Subject: Re: [sebhc] Re: H8 supply and demand

 

Who used 16-Hard Sector disks? Northstar? I suppose if you were ambitious you could modify the H17 ROM timings to use these… (like seriously ambitious…) I presume sectors were 128 bytes?

To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/8C2D3222-867B-4C66-8CD3-52E04A08BE5F%40gmail.com.

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