ID UV erasable PROMS used on an IBM PC board?

D. Resor organlists1 at
Tue Mar 22 05:03:31 CDT 2022

I've taken and uploaded some larger easy to view images of the processor board component and solder sides.

One plus is the eproms are socketed.  

I've uploaded an image showing the silk screening stamp on the underside of the eproms.

Now that I look closer at the Power Supply PWB I see it too is filled with proprietarily marked parts (sigh).

Big Blue's curse continues.

Interestingly Xerox didn’t do this with the Star 6085 Workstation.  The full service manuals are available for download.  I believe the 8010 is the same way.

I suppose I can email my contact at IBM archives and inquire about circuit diagrams...  It never hurts to ask.

I have the MiniPro TL866II Plus programmer.  It does have the ability to read the ID of ICs. Setup requires you first select IC p/n number from the list, and then it verifies the data prior to a read or write.

It would be nice if it could ID the IC automatically.   I realize there are probably too many variables to do this safely without risk of destroying the EPROM and/or the data written on it.

Don Resor

-----Original Message-----
From: cctalk <cctalk-bounces at> On Behalf Of Glen Slick via cctalk
Sent: Monday, March 21, 2022 9:17 PM
To: General Discussion: On-Topic and Off-Topic Posts <cctalk at>
Subject: Re: ID UV erasable PROMS used on an IBM PC board?

On Mon, Mar 21, 2022 at 8:25 PM Chuck Guzis via cctalk <cctalk at> wrote:
> The PROMs are most likely house-labeled Intel commodity parts with 
> JEDEC-standard pinouts, so it should be fairly easy, using an EPROM 
> reader, to figure out if these are 8KB, 16KB, 32KB or 64KB devices.

Some device programmers can read the manufacturer and device ID codes from a device, if they are implemented. That would be another way to check for a Intel standard part.

Intel 2764 - 89h / 02h
Intel 2764A - 89h / 08h
Intel 27C64 - 89h / 07h

Intel 27128 - 89h / 83h
Intel 27128A - 89h / 89h
Intel 27C128 - 89h / FCh

Intel 27256 - 89h / 04h
Intel 27C256 - 89h / 8Ch

Intel 27512 - 89h / 0Dh
Intel 27C512 - 89h / FDh

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