mystery 1702 eprom boards on ebay. Intel?
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craig andrews
Jun 23, 2026, 2:59:33 PMJun 23
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Since the group did so well figuring out Jon's mystery kit, what about these items on ebay. The seller claims they are intel boards. Claims it is an IMM 8-60 for item 366452390828 and S-100 for item 366434769217. Of course neither is correct but the seller was not exactly gracious when i suggested he correct the titles.
Does anyone think these are actually intel boards? Maybe someone else can try asking for photographs of the backside, but from the front the ASSY number and no PWA number just don't shout 'intel' to me.
Jon Hales
Jun 23, 2026, 3:49:37 PMJun 23
to intel-...@googlegroups.com
Hi Craig
The suspicion that there is an Intel connection with these boards (ten boards of the same type offered by the seller) perhaps follows from the use of 1702A parts. It's possible these were Intel designs - in the early 1970s, Intel was (primarily) a specialist in memory parts and offered very diverse modules to match systems manufactured at the time. Some examples can be seen in early Data Catalogs. But it's more likely that another manufacturer designed the board for 1702As as it was the only EPROM for some time.
Bear in mind that Intel took some time (e.g. prior to 1975) to adopt the PWA / PWB coding of its boards.
I agree with you that there's no hint that these boards related to Intellec or S100 systems.
Regards
Jon
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William Beech
Jun 24, 2026, 7:10:47 PMJun 24
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Guys
I suspect this is the Intellec 8 or Intellec 8I equivalent to the MDS-210 auxiliary ROM board that Herb has on this page: https://www.retrotechnology.com/restore/mon80_proms.html. I would like to disassemble the ROMs but sure as hell not paying $529 for it.
The imm-8-60 is a parallel I/O board for the Intellec 8 or Intellec 8I which may be how the P16 50-pin ribbon interfaces to these systems.
Bill
I suspect this is the Intellec 8 or Intellec 8I equivalent to the MDS-210 auxiliary ROM board that Herb has on this page: https://www.retrotechnology.com/restore/mon80_proms.html. I would like to disassemble the ROMs but sure as hell not paying $529 for it.
The imm-8-60 is a parallel I/O board for the Intellec 8 or Intellec 8I which may be how the P16 50-pin ribbon interfaces to these systems.
Bill
To view this discussion visit https://groups.google.com/d/msgid/intel-devsys/CANPXPJkC7zcfrJcC57%3Dd5QX9FJbfhZPSVdBymuMLAB2gtd9Upw%40mail.gmail.com.
Herbert Johnson
Jun 25, 2026, 12:55:04 AMJun 25
to intel-...@googlegroups.com, William Beech
Bill, there's *nine* of these boards for sale, the lowest price is about
$170 or so. HOwever if you "follow" the auction, "add it to your list",
you'll probably get a lower price offered to you for a few days.
It's plausible some 8008 or 8080 board had a memory interface for such
boards like this. This board is good for about 4K bytes. I don't think
it would be a "parallel interface", to be transparent it would have to
straddle the address and data lines.
I'm suspicious of those two empty sockets all alone on the edge of the
board. Are they for some 4004 4040 memory-interface chips? Are they some
other kind of connection to another board?
But as you have said, I don't know if all that's worth a $100+ bet.
Worse would be if one of the PROMs failed. There's cheaper mysteries to
pursue with better odds.
On the other hand, if you can get 16 1702A's for some $100+ value,
that's not an awful price. Why you'd need so many I'm not sure.
Regards Herb
--
Herb Johnson, New Jersey USA
http://www.retrotechnology.com or .net
preserve and restore 1970's personal computing
email: hjohnson @ retrotechnology dot com
or try later at herbjohnson @ comcast dot net
$170 or so. HOwever if you "follow" the auction, "add it to your list",
you'll probably get a lower price offered to you for a few days.
It's plausible some 8008 or 8080 board had a memory interface for such
boards like this. This board is good for about 4K bytes. I don't think
it would be a "parallel interface", to be transparent it would have to
straddle the address and data lines.
I'm suspicious of those two empty sockets all alone on the edge of the
board. Are they for some 4004 4040 memory-interface chips? Are they some
other kind of connection to another board?
But as you have said, I don't know if all that's worth a $100+ bet.
Worse would be if one of the PROMs failed. There's cheaper mysteries to
pursue with better odds.
On the other hand, if you can get 16 1702A's for some $100+ value,
that's not an awful price. Why you'd need so many I'm not sure.
Regards Herb
>> s-l1600.jpg
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Jon Hales
Jun 25, 2026, 3:57:27 AMJun 25
to intel-...@googlegroups.com
Hi Bill
There are problems with your suggestion that the EPROM board was intended for the Intellec 8. The backplane has four slots for RAM and four for EPROM, each slot supporting 4Kb. But there was a hard limit of 16Kb total. There doesn't appear to be an opportunity for further EPROM expansion.
When later RAM devices could have increased the capacity of each board to 16Kb, hence a potential total of 64Kb, the constraint was the PSUs.
Best regards
Jon
To view this discussion visit https://groups.google.com/d/msgid/intel-devsys/eb1db461-63c7-4c01-86fd-297fa1ea1ae3%40nj7p.org.
William Beech
Jun 25, 2026, 2:29:33 PMJun 25
to intel-...@googlegroups.com
Herb and Jon,
I believe this is an Intel board. In the Intellec 8/8I days, the numbering was in limbo.
This is NOT a board for the bus. Therefore, it would not take up space in memory map. I believe it was meant to interface via the imm-8-60 parallel I/O board. It may contain a ROM'ed version of the assembler and editor. Again, without reading the ROM's, we have no idea. Faster to read the ROM's into RAM than to load paper tape.
Bill
I believe this is an Intel board. In the Intellec 8/8I days, the numbering was in limbo.
This is NOT a board for the bus. Therefore, it would not take up space in memory map. I believe it was meant to interface via the imm-8-60 parallel I/O board. It may contain a ROM'ed version of the assembler and editor. Again, without reading the ROM's, we have no idea. Faster to read the ROM's into RAM than to load paper tape.
Bill
To view this discussion visit https://groups.google.com/d/msgid/intel-devsys/CANPXPJ%3DKyE_GbdKNgY64yVqFeZ1S-7-RWFHDQLRtXPckrHcb0A%40mail.gmail.com.
craig andrews
Jun 25, 2026, 2:42:57 PMJun 25
to intel-devsys
The intellec 4 and 8 backplanes brought the bus out to 50 pin headers. The slots are assigned specific memory ranges, but as bill says if the parallel I/O were used or if the backplane headers were used and expansion board could be placed anywhere in memory which would be nice if, as in his example, wanted the ASM to be somewhere other than in system main ROM. Herb mentioned the two unused sockets. One possibility is that they are used to configure the address of the board just as the backplane does memory mapping.
I can use the 1702s and would like to see their contents. Also give me a chance to see if they can hang on my intellec 8 workalike. I will make a $100 +/- offer on one or two of the cheaper ones and see what happens. Unlikely to accept, of course, if someone here has already offered him more. so let me know if i am wasting my time.
Herbert Johnson
Jun 25, 2026, 3:03:23 PMJun 25
to intel-...@googlegroups.com, craig andrews
Bill, there's no direct evidence that Intel produced this PC board. They
readily put their Intel name on boards they produced. Their corporate
goal was to sell memory chips! Every product was advertising for Intel!
If there were an Intel name on these boards, the seller would take a
zoom photo of it.
In the era, a number of companies built 4004 and 4040 based controllers,
or added those processors to their instruments to perform functions.
I've found them over the decades. It would be natural for them to
progress to 8008 and 8080 products. Along the way, some of them might
"backfill" their older products with some kind of memory card, RAM or
ROM. Pro-Log sold 4004 and 4040 products with memory daughter boards.
And updated designs might still use old memory parts on a daughterboard.
"the proof of the pudding is in the eating". The ROM contents will
likely prove the origin. Who wants to bet $100-ish on the ROM contents?
And following PC traces will prove how this thing was hooked up.
Well, if Craig wants to step up to the plate, why not? It's a mystery,
he likes these mysteries. He'll get a supply of 1702A's, no cheap items,
for $100-ish. And Craig, no big secret, watching eBay items often leads
to seller's offers at various discounts. The seller has NINE of these to
move ...
> I will make a $100 +/- offer on one or two of the cheaper ones and see what happens. Unlikely to accept, of course, if someone here has already offered him more. so let me know if i am wasting my time.
oops, he has EIGHT of these now. Who pulled the trigger, I wonder? ;)
You know, if we collectively wanted to, we could fund some one of us to
buy stuff like this. Skip a Whopper or Big Mac, and help one of us buy
something to reverse out. There's no shame in asking to spread the load
to solve a riddle, and whoever steps up has a different risk/reward
calculus.
Regards Herb
On 6/25/2026 2:42 PM, craig andrews wrote:
> The intellec 4 and 8 backplanes brought the bus out to 50 pin headers.
> The slots are assigned specific memory ranges, but as bill says if the
> parallel I/O were used or if the backplane headers were used and
> expansion board could be placed anywhere in memory which would be nice
> if, as in his example, wanted the ASM to be somewhere other than in
> system main ROM. Herb mentioned the two unused sockets. One
> possibility is that they are used to configure the address of the board
> just as the backplane does memory mapping.
> I can use the 1702s and would like to see their contents. Also give me
> a chance to see if they can hang on my intellec 8 workalike. I will
> make a $100 +/- offer on one or two of the cheaper ones and see what
> happens. Unlikely to accept, of course, if someone here has already
> offered him more. so let me know if i am wasting my time.
>
> On Thursday, June 25, 2026 at 11:29:33 AM UTC-7 William Beech wrote:
>
> __
>> <https://www.retrotechnology.com/restore/mon80_proms.html>. I
readily put their Intel name on boards they produced. Their corporate
goal was to sell memory chips! Every product was advertising for Intel!
If there were an Intel name on these boards, the seller would take a
zoom photo of it.
In the era, a number of companies built 4004 and 4040 based controllers,
or added those processors to their instruments to perform functions.
I've found them over the decades. It would be natural for them to
progress to 8008 and 8080 products. Along the way, some of them might
"backfill" their older products with some kind of memory card, RAM or
ROM. Pro-Log sold 4004 and 4040 products with memory daughter boards.
And updated designs might still use old memory parts on a daughterboard.
"the proof of the pudding is in the eating". The ROM contents will
likely prove the origin. Who wants to bet $100-ish on the ROM contents?
And following PC traces will prove how this thing was hooked up.
Well, if Craig wants to step up to the plate, why not? It's a mystery,
he likes these mysteries. He'll get a supply of 1702A's, no cheap items,
for $100-ish. And Craig, no big secret, watching eBay items often leads
to seller's offers at various discounts. The seller has NINE of these to
move ...
> I will make a $100 +/- offer on one or two of the cheaper ones and see what happens. Unlikely to accept, of course, if someone here has already offered him more. so let me know if i am wasting my time.
You know, if we collectively wanted to, we could fund some one of us to
buy stuff like this. Skip a Whopper or Big Mac, and help one of us buy
something to reverse out. There's no shame in asking to spread the load
to solve a riddle, and whoever steps up has a different risk/reward
calculus.
Regards Herb
On 6/25/2026 2:42 PM, craig andrews wrote:
> The intellec 4 and 8 backplanes brought the bus out to 50 pin headers.
> The slots are assigned specific memory ranges, but as bill says if the
> parallel I/O were used or if the backplane headers were used and
> expansion board could be placed anywhere in memory which would be nice
> if, as in his example, wanted the ASM to be somewhere other than in
> system main ROM. Herb mentioned the two unused sockets. One
> possibility is that they are used to configure the address of the board
> just as the backplane does memory mapping.
> I can use the 1702s and would like to see their contents. Also give me
> a chance to see if they can hang on my intellec 8 workalike. I will
> make a $100 +/- offer on one or two of the cheaper ones and see what
> happens. Unlikely to accept, of course, if someone here has already
> offered him more. so let me know if i am wasting my time.
>
> On Thursday, June 25, 2026 at 11:29:33 AM UTC-7 William Beech wrote:
>
>>> s-l1600.jpg
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craig andrews
Jun 25, 2026, 3:03:32 PMJun 25
to intel-devsys
Did they make an I/O with 50 pin headers? The Imm8-61 had 40 pin headers and i think the 8-60 also had 40 pin.
On Thursday, June 25, 2026 at 11:29:33 AM UTC-7 William Beech wrote:
William Beech
Jun 25, 2026, 3:09:38 PMJun 25
to intel-...@googlegroups.com
Craig,
I went for the full price on the $169 offering. It will take me awhile to read those 1702As.
Bill
I went for the full price on the $169 offering. It will take me awhile to read those 1702As.
Bill
To view this discussion visit https://groups.google.com/d/msgid/intel-devsys/02d275db-3de9-466f-afa9-823c54e51d13n%40googlegroups.com.
andre...@gmail.com
Jun 25, 2026, 3:53:18 PMJun 25
to intel-...@googlegroups.com
Bill-
Very good. At least we will reach the end goal of reading the EPROMs. I made an offer on two boards in case there was too much bit rot. When you get your board and can send photographs, then we can re-evaluate their worth.
Maybe now that you are a paying customer, you can pump the seller for more information.
There is no doubt these are quality boards and went through some decent QC considering there are at least three stamps on the board. The Beckman terminator packs, trace layout, all make an argument to a major manufacturer. Q2 looks a little dodgy but the rest is very nice. Since this board only has one 50 pin header and neither 50 pin on the intellect 8 has all the signals needed for memory access, I have talked myself out of the board being intended for use with the intellect 8.
Regards to all
craig
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William Beech
Jun 25, 2026, 8:43:13 PMJun 25
to intel-...@googlegroups.com
Herb,
I pulled the trigger for the cheapest one of them. I note all seem to
have the same array of chips. Some of the more expensive have broken
connectors and sockets.
The code contained in the ROMs will tell us what we need to know. I
believe, in many cases, I have bet $100 on the ROM contents. We have
several versions of various Monitor programs because of this!
Yes, since they appear to all contain the same ROM content, we could
have done a group buy of one for the content. But I like these projects.
Bill
I pulled the trigger for the cheapest one of them. I note all seem to
have the same array of chips. Some of the more expensive have broken
connectors and sockets.
The code contained in the ROMs will tell us what we need to know. I
believe, in many cases, I have bet $100 on the ROM contents. We have
several versions of various Monitor programs because of this!
Yes, since they appear to all contain the same ROM content, we could
have done a group buy of one for the content. But I like these projects.
Bill
William Beech
Jun 25, 2026, 8:51:46 PMJun 25
to intel-...@googlegroups.com
Guys,
The imm8-60 had 50-pin connectors.
Cables can be built to adapt any to any.
Bill
The imm8-60 had 50-pin connectors.
Cables can be built to adapt any to any.
Bill
To view this discussion visit https://groups.google.com/d/msgid/intel-devsys/4f719628-6758-4c04-8522-0958cf3a3b4bn%40googlegroups.com.
William Beech
Jun 25, 2026, 9:00:50 PMJun 25
to intel-...@googlegroups.com
Craig,
Yes, bit rot is a concern. Thanks!
Agree with your evaluation of the boards. Pricing does not match condition of the boards. But my cut is that all these boards contain the same code. Lets see what we have!
Bill
Yes, bit rot is a concern. Thanks!
Agree with your evaluation of the boards. Pricing does not match condition of the boards. But my cut is that all these boards contain the same code. Lets see what we have!
Bill
To view this discussion visit https://groups.google.com/d/msgid/intel-devsys/1caa01dd04dc%24436e9620%24ca4bc260%24%40gmail.com.
andre...@gmail.com
Jul 7, 2026, 5:26:06 PMJul 7
to intel-...@googlegroups.com
I forgot to follow-up. The seller accepted my original offer from 6/25. I was sort of hoping they wouldn’t since Bill also purchased a board, but I couldn’t withdraw the offer. It has taken them a while to ship… or at least they have finally purchased the label today…. I will report back if I ever get the boards and then the eproms read.
To view this discussion visit https://groups.google.com/d/msgid/intel-devsys/4f204e7c-b5e2-42fa-a527-576cfa648618%40nj7p.org.
William Beech
Jul 8, 2026, 3:05:00 AMJul 8
to intel-...@googlegroups.com
They just got back to me, as well. It's on the way.
Bill
Bill
To view this discussion visit https://groups.google.com/d/msgid/intel-devsys/e03301dd0e57%2436aa58a0%24a3ff09e0%24%40gmail.com.
craig andrews
Jul 10, 2026, 3:39:43 PMJul 10
to intel-devsys
I received my mystery boards, there was certainly no intent to make sure they shipped without getting damaged, but the eproms were all there.
Of interest -- the two unpopulated sockets on the edge are, in fact, wire wrap sockets (but w/o any wire). I am sure the various post office employees did not appreciate that these pins were all poking out of the envelope.
there are no indications on solder side that these are intel boards, just a FAB Number 600581 REV D which is the component side ASSY NO plus one. But there is an interesting logo on *one* of the boards which is an OR gate with the letters RC inside.
I read the eproms on one of the boards and did not see any text strings other than a pirate's "ARRRRRRR". To me, the contents do not look like MCS4 / MCS8, or MCS80 opcodes. Hex file attached, perhaps someone else can make sense of the contents. I also need to read the other board's EPROMs and then do some multiple reads.
I read the eproms as 8-bit values, but now looking at the board i should have read them in pairs as 16-bit values. With that in mind, the pirate's RRRRRR makes more sense as the high half of a16-bit lookup table i.e., 0x52FA, 0x52F6, 0x52F4, 0x52F3, etc.. Maybe the whole file will make more sense when arranged as 16 bit values. we shall see.
I am interested to see what Bill finds with his board
Regards
Craig
Herbert Johnson
Jul 10, 2026, 6:09:52 PMJul 10
to intel-...@googlegroups.com, craig andrews
an oddity about 1702's, is that their data is "inverted". This is
unique for the 1702 and often forgotten. So I binaried Craig's hex file
and inverted the data with a program I threw together. (My program works
because when I invert twice I get the original uninverted binary.)
Attached is Craig's hex, my bin of it, and my inverted bin of it. No
magic produced, no bunches of text strings revealed.
Since there's a couple board-sets-of-ROMs in contention, probably the
priority is to read all of their ROMS and cross-check, hope all or most
of the codes are the same across boards. MIght be useful to do simple
stats of values ROM to ROM. If one ROM has skewed values from the
others, that may suggest a bad ROM or bad read.
I'd look for continuity between ROMS (around 0100H page intervals),
assuming code crosses pages. But I don't see anything awful by eye. I
don't see "stuck bits". Someone with a spreadsheet, might see if there's
a distribution of byte values that's informative. It might identify
common instructions which are often register moves for instance. MIght
be useful to do simple stats of values ROM to ROM. If one ROM has skewed
values from the others, that may suggest a bad ROM or bad read.
Board holders, are in a position to examine the PC board traces, to see
how the data lines are bunched up to the connectors. See if there's a
4-bit data path, or 8, or 16. And what's the relationship of those
wire-wrap sockets to the RAM chips, trace those lines out.
Might confirm the addressing order of the chips, but at the moment
that's not a priority, as no single ROM makes sense.
Craig might report on date-codes on chips, see if the date of
manufacture might be guessed at. But use of 1702A's suggests early days.
There were lots of odd processors in the early days beyond Intel. and,
custom discrete-chip processors too. Even so, one might expect ASCII
strings anyway (EBCDIC? I checked, nope).
As far as Craig's PC board trade symbol, it could be an "AC", could be
an "RC". I did a Google image search, but it decided to only look at
hallmarks on silver and china, no useful result. It may be the brand of
the PC board maker, not the brand of the company who laid out the board.
Regards Herb
On 7/10/2026 3:39 PM, craig andrews wrote:
> I read the eproms on one of the boards and did not see any text strings
> other than a pirate's "ARRRRRRR". To me, the contents do not look like
> MCS4 / MCS8, or MCS80 opcodes. Hex file attached, perhaps someone else
> can make sense of the contents. I also need to read the other board's
> EPROMs and then do some multiple reads.
unique for the 1702 and often forgotten. So I binaried Craig's hex file
and inverted the data with a program I threw together. (My program works
because when I invert twice I get the original uninverted binary.)
Attached is Craig's hex, my bin of it, and my inverted bin of it. No
magic produced, no bunches of text strings revealed.
Since there's a couple board-sets-of-ROMs in contention, probably the
priority is to read all of their ROMS and cross-check, hope all or most
of the codes are the same across boards. MIght be useful to do simple
stats of values ROM to ROM. If one ROM has skewed values from the
others, that may suggest a bad ROM or bad read.
I'd look for continuity between ROMS (around 0100H page intervals),
assuming code crosses pages. But I don't see anything awful by eye. I
don't see "stuck bits". Someone with a spreadsheet, might see if there's
a distribution of byte values that's informative. It might identify
common instructions which are often register moves for instance. MIght
be useful to do simple stats of values ROM to ROM. If one ROM has skewed
values from the others, that may suggest a bad ROM or bad read.
Board holders, are in a position to examine the PC board traces, to see
how the data lines are bunched up to the connectors. See if there's a
4-bit data path, or 8, or 16. And what's the relationship of those
wire-wrap sockets to the RAM chips, trace those lines out.
Might confirm the addressing order of the chips, but at the moment
that's not a priority, as no single ROM makes sense.
Craig might report on date-codes on chips, see if the date of
manufacture might be guessed at. But use of 1702A's suggests early days.
There were lots of odd processors in the early days beyond Intel. and,
custom discrete-chip processors too. Even so, one might expect ASCII
strings anyway (EBCDIC? I checked, nope).
As far as Craig's PC board trade symbol, it could be an "AC", could be
an "RC". I did a Google image search, but it decided to only look at
hallmarks on silver and china, no useful result. It may be the brand of
the PC board maker, not the brand of the company who laid out the board.
Regards Herb
On 7/10/2026 3:39 PM, craig andrews wrote:
> I read the eproms on one of the boards and did not see any text strings
> other than a pirate's "ARRRRRRR". To me, the contents do not look like
> MCS4 / MCS8, or MCS80 opcodes. Hex file attached, perhaps someone else
> can make sense of the contents. I also need to read the other board's
> EPROMs and then do some multiple reads.
craig andrews
Jul 11, 2026, 12:45:21 AMJul 11
to Herbert Johnson, intel-...@googlegroups.com
As I recall, the 1702A data is complemented when programming —- in a confusing way…. 0V = Logic 0, -48v = Logic 1. The programmers I have worked on (e.g., reproduction MIL MOD 8) upshifted everything by 48v so when programming, a logic 0 would be 48v and logic 1 is 0V. The address is even worse since it is switched from complemented then returned to normal during the programming cycle right before the programming pulse. But during a read, I think address and data lines are both normal logic.
I didn’t have time to really look at the boards, but I think the CS goes to chips in pairs: 0/1, 2/3, … E/F. if that is the case, I need to interleave the low/high bytes to form a 16 bit value and then maybe there are sensible ascii strings within.
Maybe I’m wrong, but if this machine has a 16 bit memory access, I suspect it isn’t related to any of the 4 or 8 bit microprocessor platforms I was hoping for. So I will probably back burner much reverse engineering.
Craig.
> On Jul 10, 2026, at 3:09 PM, Herbert Johnson <hjoh...@retrotechnology.com> wrote:
>
> an oddity about 1702's, is that their data is "inverted". This is
> <1702.zip>
I didn’t have time to really look at the boards, but I think the CS goes to chips in pairs: 0/1, 2/3, … E/F. if that is the case, I need to interleave the low/high bytes to form a 16 bit value and then maybe there are sensible ascii strings within.
Maybe I’m wrong, but if this machine has a 16 bit memory access, I suspect it isn’t related to any of the 4 or 8 bit microprocessor platforms I was hoping for. So I will probably back burner much reverse engineering.
Craig.
> On Jul 10, 2026, at 3:09 PM, Herbert Johnson <hjoh...@retrotechnology.com> wrote:
>
> an oddity about 1702's, is that their data is "inverted". This is
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