Re: ID UV erasable PROMS used on an IBM PC board?
On Wed, Mar 23, 2022 at 10:38 AM Chris Elmquist via cctalk wrote: > > On Wednesday (03/23/2022 at 04:18PM +0100), Christian Corti via cctalk wrote: > > > > I didn't even know that primitive EPROMs have device IDs... > > Without looking for a data book, how is the ID mechanism implemented? > > Intel called it "Intelligent Identifier(tm) Mode". > > From page 5-43 of my 1991 Intel Memory Products book, for the 27256, > > You put Vh (+12V) on address A9 and then, > > with A0=0, you will read out the manufacturer ID > with A0=1, you will read out the device ID > > Chris It is interesting that the Table 1 Operating Modes referenced above on page 5-43 says that the Manufacturer ID is 89H for UV erasable Cerdip parts, and 88H for OTP Plastic parts. The interesting thing is that previously Intel data books (e.g. 1983_Memory_Component_Handbook.pdf, page 4-28) said "All identifiers for manufacturer and device codes will possess odd parity, with the MSB (D7) defined as the parity bit". The Manufacturer ID of 88H does not have odd parity. I don't know if the odd parity requirement was removed, or if this is an exception.
Re: ID UV erasable PROMS used on an IBM PC board?
On Wednesday (03/23/2022 at 04:18PM +0100), Christian Corti via cctalk wrote: > On Wed, 23 Mar 2022, Chris Elmquist wrote: > > More interesting. If the programming algorithms remained the same then I > > guess it is just an issue for the programming system-- when it auto-IDs, > > it should display (and allow!) 27C256A instead of 27C256. > > > > I guess the next question is whether the programming algorithms really > > are the same between the 8CH and the 8DH variants?? > > > > My limited testing suggests they are at least compatible since my 8DH > > appears to be working when programmed as an 8CH. > > I didn't even know that primitive EPROMs have device IDs... > Without looking for a data book, how is the ID mechanism implemented? Intel called it "Intelligent Identifier(tm) Mode". From page 5-43 of my 1991 Intel Memory Products book, for the 27256, You put Vh (+12V) on address A9 and then, with A0=0, you will read out the manufacturer ID with A0=1, you will read out the device ID Chris -- Chris Elmquist
Re: ID UV erasable PROMS used on an IBM PC board?
On 3/23/22 08:18, Christian Corti via cctalk wrote: > On Wed, 23 Mar 2022, Chris Elmquist wrote: >> More interesting. If the programming algorithms remained the same then I >> guess it is just an issue for the programming system-- when it auto-IDs, >> it should display (and allow!) 27C256A instead of 27C256. > I think I first ran into this with the Seeq "Silicon Signature" PROMs. In my case, I think they were 27128s. --Chuck
Re: ID UV erasable PROMS used on an IBM PC board?
On Wed, 23 Mar 2022, Chris Elmquist wrote: More interesting. If the programming algorithms remained the same then I guess it is just an issue for the programming system-- when it auto-IDs, it should display (and allow!) 27C256A instead of 27C256. I guess the next question is whether the programming algorithms really are the same between the 8CH and the 8DH variants?? My limited testing suggests they are at least compatible since my 8DH appears to be working when programmed as an 8CH. I didn't even know that primitive EPROMs have device IDs... Without looking for a data book, how is the ID mechanism implemented? Christian
Re: ID UV erasable PROMS used on an IBM PC board?
On Tuesday (03/22/2022 at 08:09PM -0700), Glen Slick wrote: > On Tue, Mar 22, 2022 at 12:25 PM Chris Elmquist wrote: > > > > On Tuesday (03/22/2022 at 12:20PM -0700), Glen Slick wrote: > > > On Tue, Mar 22, 2022 at 11:56 AM Chris Elmquist wrote: > > > > > > > > Trying not to hijack the thread too much but I have an Intel D27C256-200 > > > > here in my TL866II+ programmer and it returns ID 89h / 8Dh. > > > > > > > > > > http://www.bitsavers.org/components/intel/_dataBooks/1993_Intel_Memory_Products.pdf > > > Page 5-78 (Page 1201 of the PDF) > > > Table 1. Mode Selection > > > Intelligent Identifier - Manufacturer 89H > > > Intelligent Identifier - Device 8DH > > > That is for the A27C256 "Automotive" rated version. > > > > > > My BP Microsystems BP-1610 device programmer software doesn't have an > > > entry for that one either. > > > > Interesting. Thanks Glen. The part is clearly labeled as > > "D27C256-200V10" so they must not have gotten around to changing the D > > to an A :-) > > (Flogging a dead horse here slightly) > > Just took a look at a previous version of that Intel databook: > http://www.bitsavers.org/components/intel/_dataBooks/1991_Intel_Memory_Products.pdf > > Page 5-56 (Page 325 of the PDF) 27C256 > Table 1. Mode Selection > Intelligent Identifier - Manufacturer 89H > Intelligent Identifier - Device 8DH > NOTES: > 4. Programming equipment may also refer to this device as the 27C256A. > Older devices may have device ID = 8CH > > So apparently the Device ID change is not specific to the A27C256 > "Automotive" rated version, just that in the 1993 version of the > databook where I first looked the only EPROMs listed are the > "Automotive" ones. More interesting. If the programming algorithms remained the same then I guess it is just an issue for the programming system-- when it auto-IDs, it should display (and allow!) 27C256A instead of 27C256. I guess the next question is whether the programming algorithms really are the same between the 8CH and the 8DH variants?? My limited testing suggests they are at least compatible since my 8DH appears to be working when programmed as an 8CH. Chris -- Chris Elmquist
Re: ID UV erasable PROMS used on an IBM PC board?
On 3/22/22 21:32, dwight via cctalk wrote: > Years ago when I was at Intel, they would take EPROMs that had only a few > defects and attempt to program them with specific applications. They would > then usually paint the window black and put on that particular product > number. When we needed EPROMs in the lab, we would take a pile of these that > were no longer used and scrape the paint off the window. Some would take the > desired program and some wouldn't. > I suspect that they can fuse identify specific bad EPROMs to use for such > harvesting. The fused value may be laser blown as well. My guess is that that > is the reason for the different ID number. If it will take pre-programming > with a particular data, it is worth harvesting. > This way they can find value in an otherwise unsellable product. I doubt the > harvesting methods have changed much over the years. That's not surprising. Probably cheaper even for IBM than mask-programmed PROMs. --Chuck
Re: ID UV erasable PROMS used on an IBM PC board?
Years ago when I was at Intel, they would take EPROMs that had only a few defects and attempt to program them with specific applications. They would then usually paint the window black and put on that particular product number. When we needed EPROMs in the lab, we would take a pile of these that were no longer used and scrape the paint off the window. Some would take the desired program and some wouldn't. I suspect that they can fuse identify specific bad EPROMs to use for such harvesting. The fused value may be laser blown as well. My guess is that that is the reason for the different ID number. If it will take pre-programming with a particular data, it is worth harvesting. This way they can find value in an otherwise unsellable product. I doubt the harvesting methods have changed much over the years. Dwight From: cctalk on behalf of Paul Berger via cctalk Sent: Tuesday, March 22, 2022 1:14 PM To: D. Resor via cctalk Subject: Re: ID UV erasable PROMS used on an IBM PC board? I can tell you what some of the chips are on the power supply board, but the list I have is mostly TTL parts 1582684 LM324 1582606 74LS74 F/F D-TYPE DUAL +E/T 2392122 7417BUF/DVR HEX O/C (TPD0 30NS) 8272147 74LS05 INV HEX O/C Aside from the house numbering of parts which is not unique to IBM, IBM had their own foundry for many years so you will encounter custom parts for which there is no industry equivalent, this is also not unique to IBM, I have some HP computers that many of the parts are house numbered, and HP also manufactured their own chips so there are some parts that are unobtanium as well. Paul. On 2022-03-22 06:40, D. Resor via cctalk wrote: > There are a few other problems. > > The power supply does not power up. Three of it's four voltages are missing > (+5vdc, +8.5vdc, +13vdc). With no connections to the power supply board, > the +5vdc measures 4.92vdc while the other two voltages are still zero > volts. > > The second issue I found upon removing the driver and processor board is > moisture had entered the typewriter's electronics and the connector between > the two boards has corrosion on many of the pins and on the PWB near the > connector. > > I do not have access to a microscope. > > I know it has been explained to me elsewhere that UV exposure from > florescent lamps can erase the proms. The way I understand is the glass of > the florescent lamp filters out any UV radiation (as does the piece of glass > mounted in front of quartz halogen lighting). In order that a UV lamp can > operate correctly the tube must be made of quartz, not glass. > > Am I wrong here? > > Don Resor > > From: dwight > Sent: Monday, March 21, 2022 4:50 PM > To: 'General Discussion: On-Topic and Off-Topic Posts' > ; D. Resor > Subject: Re: ID UV erasable PROMS used on an IBM PC board? > > The dies look to have consistent wire bonding. That would mean they are one > of the standard EPROMs made by Intel, just preprogrammed by Intel before > shipping. The numbers wouldn't be intel numbers they would be IBMs inventory > numbers. My guess is that they are 2732s. You might use a microscope and > look at the edges of the dies. They often have the die type in the metal > layers around the edge some place. Avoid using florescent ring lights as a > large amount of UVC leaks from these. White LED are or incandescent lights. > Also power it up and note which pins look to have signals. if any of the > lines have what looks like a constant voltage measure it to the nearest .01 > volts if you can. That will help determine if it is driven by a signal or a > hard tied wire. Lower left and upper right should be ground and power pins. > Dwight > > >_ > > From: cctalk on behalf of D. Resor via > cctalk > Sent: Sunday, March 20, 2022 6:53 PM > To: 'General Discussion: On-Topic and Off-Topic Posts' > > Subject: ID UV erasable PROMS used on an IBM PC board? > > I cannot find a datasheet by any of the numbers silkscreened on these ICs. > > Could these be proprietary IBM P/N numbers? > > https://www.dropbox.com/s/f6rvemx9ldbbv5x/EPROMS1.jpg?dl=0 > > No need for a Dropbox account, close the login pop up and you can view the > image. > > Thanks > > Don Resor > >
Re: ID UV erasable PROMS used on an IBM PC board?
On Tue, Mar 22, 2022 at 12:25 PM Chris Elmquist wrote: > > On Tuesday (03/22/2022 at 12:20PM -0700), Glen Slick wrote: > > On Tue, Mar 22, 2022 at 11:56 AM Chris Elmquist wrote: > > > > > > Trying not to hijack the thread too much but I have an Intel D27C256-200 > > > here in my TL866II+ programmer and it returns ID 89h / 8Dh. > > > > > > > http://www.bitsavers.org/components/intel/_dataBooks/1993_Intel_Memory_Products.pdf > > Page 5-78 (Page 1201 of the PDF) > > Table 1. Mode Selection > > Intelligent Identifier - Manufacturer 89H > > Intelligent Identifier - Device 8DH > > That is for the A27C256 "Automotive" rated version. > > > > My BP Microsystems BP-1610 device programmer software doesn't have an > > entry for that one either. > > Interesting. Thanks Glen. The part is clearly labeled as > "D27C256-200V10" so they must not have gotten around to changing the D > to an A :-) (Flogging a dead horse here slightly) Just took a look at a previous version of that Intel databook: http://www.bitsavers.org/components/intel/_dataBooks/1991_Intel_Memory_Products.pdf Page 5-56 (Page 325 of the PDF) 27C256 Table 1. Mode Selection Intelligent Identifier - Manufacturer 89H Intelligent Identifier - Device 8DH NOTES: 4. Programming equipment may also refer to this device as the 27C256A. Older devices may have device ID = 8CH So apparently the Device ID change is not specific to the A27C256 "Automotive" rated version, just that in the 1993 version of the databook where I first looked the only EPROMs listed are the "Automotive" ones.
Re: ID UV erasable PROMS used on an IBM PC board?
I can tell you what some of the chips are on the power supply board, but the list I have is mostly TTL parts 1582684 LM324 1582606 74LS74 F/F D-TYPE DUAL +E/T 2392122 7417 BUF/DVR HEX O/C (TPD0 30NS) 8272147 74LS05 INV HEX O/C Aside from the house numbering of parts which is not unique to IBM, IBM had their own foundry for many years so you will encounter custom parts for which there is no industry equivalent, this is also not unique to IBM, I have some HP computers that many of the parts are house numbered, and HP also manufactured their own chips so there are some parts that are unobtanium as well. Paul. On 2022-03-22 06:40, D. Resor via cctalk wrote: There are a few other problems. The power supply does not power up. Three of it's four voltages are missing (+5vdc, +8.5vdc, +13vdc). With no connections to the power supply board, the +5vdc measures 4.92vdc while the other two voltages are still zero volts. The second issue I found upon removing the driver and processor board is moisture had entered the typewriter's electronics and the connector between the two boards has corrosion on many of the pins and on the PWB near the connector. I do not have access to a microscope. I know it has been explained to me elsewhere that UV exposure from florescent lamps can erase the proms. The way I understand is the glass of the florescent lamp filters out any UV radiation (as does the piece of glass mounted in front of quartz halogen lighting). In order that a UV lamp can operate correctly the tube must be made of quartz, not glass. Am I wrong here? Don Resor From: dwight Sent: Monday, March 21, 2022 4:50 PM To: 'General Discussion: On-Topic and Off-Topic Posts' ; D. Resor Subject: Re: ID UV erasable PROMS used on an IBM PC board? The dies look to have consistent wire bonding. That would mean they are one of the standard EPROMs made by Intel, just preprogrammed by Intel before shipping. The numbers wouldn't be intel numbers they would be IBMs inventory numbers. My guess is that they are 2732s. You might use a microscope and look at the edges of the dies. They often have the die type in the metal layers around the edge some place. Avoid using florescent ring lights as a large amount of UVC leaks from these. White LED are or incandescent lights. Also power it up and note which pins look to have signals. if any of the lines have what looks like a constant voltage measure it to the nearest .01 volts if you can. That will help determine if it is driven by a signal or a hard tied wire. Lower left and upper right should be ground and power pins. Dwight _ From: cctalk on behalf of D. Resor via cctalk Sent: Sunday, March 20, 2022 6:53 PM To: 'General Discussion: On-Topic and Off-Topic Posts' Subject: ID UV erasable PROMS used on an IBM PC board? I cannot find a datasheet by any of the numbers silkscreened on these ICs. Could these be proprietary IBM P/N numbers? https://www.dropbox.com/s/f6rvemx9ldbbv5x/EPROMS1.jpg?dl=0 No need for a Dropbox account, close the login pop up and you can view the image. Thanks Don Resor
Re: ID UV erasable PROMS used on an IBM PC board?
On Tuesday (03/22/2022 at 12:20PM -0700), Glen Slick wrote: > On Tue, Mar 22, 2022 at 11:56 AM Chris Elmquist wrote: > > > > Trying not to hijack the thread too much but I have an Intel D27C256-200 > > here in my TL866II+ programmer and it returns ID 89h / 8Dh. > > > > http://www.bitsavers.org/components/intel/_dataBooks/1993_Intel_Memory_Products.pdf > Page 5-78 (Page 1201 of the PDF) > Table 1. Mode Selection > Intelligent Identifier - Manufacturer 89H > Intelligent Identifier - Device 8DH > That is for the A27C256 "Automotive" rated version. > > My BP Microsystems BP-1610 device programmer software doesn't have an > entry for that one either. Interesting. Thanks Glen. The part is clearly labeled as "D27C256-200V10" so they must not have gotten around to changing the D to an A :-) But, that explains it. Thanks for the digging. Chris -- Chris Elmquist
Re: ID UV erasable PROMS used on an IBM PC board?
On Tue, Mar 22, 2022 at 11:56 AM Chris Elmquist wrote: > > Trying not to hijack the thread too much but I have an Intel D27C256-200 > here in my TL866II+ programmer and it returns ID 89h / 8Dh. > http://www.bitsavers.org/components/intel/_dataBooks/1993_Intel_Memory_Products.pdf Page 5-78 (Page 1201 of the PDF) Table 1. Mode Selection Intelligent Identifier - Manufacturer 89H Intelligent Identifier - Device 8DH That is for the A27C256 "Automotive" rated version. My BP Microsystems BP-1610 device programmer software doesn't have an entry for that one either.
Re: ID UV erasable PROMS used on an IBM PC board?
On Monday (03/21/2022 at 09:17PM -0700), Glen Slick via cctalk wrote: > On Mon, Mar 21, 2022 at 8:25 PM Chuck Guzis via cctalk > 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 27256 - 89h / 04h > Intel 27C256 - 89h / 8Ch [...] Trying not to hijack the thread too much but I have an Intel D27C256-200 here in my TL866II+ programmer and it returns ID 89h / 8Dh. The TL866+software actually fails to program it if the "Check Id" feature is enabled as it complains about ID mismatch. But if I disable that, it programs correctly and works in-circuit without issue. Without disabling the Id check, there would be no way to program an Intel 27256 on this programmer since there are no other 256K-bit Intel offerings in the menu-- so I am suspecious of the situation. Any idea why some Intel 256K-bit PROMs are 89/8C and some are 89/8D?? Chris -- Chris Elmquist
Re: ID UV erasable PROMS used on an IBM PC board?
It is true that the glass blocks most of the UVC from florescent lamps. The key word here is "most". It is not a 100% block. When looking at aged data in EPROMs one should error on the side of caution. As an example, I have a pole lamp that I use a standard florescent bulb, with the typical spiral of 3 turns. I used it for about 4 hours a day for about a month when I bumped into the lamp shade. It crumbled into pieces. At the base where the lamp shade was protected from direct light of the lamp, the plastic seemed to be of full strength, even though the temperature was higher at the base. I don't know the intensity of the various levels of UV at different frequencies leaking from the lamp. I do know that it takes a specific high frequency of UV in the UVC range as a minimum to erase EPROMs. This plastic may be sensitive to UV closer to the visible spectrum. I'm only saying that one should use a lamp that has zero UVC as apposed to a lamp that has a filter reduced level of UVC. Years ago, I won a bet by allowing an EPROM to sit exposed for 3 months in an industrial setting, using florescent tube lighting. It did not erase any of the data in that condition. I suspect it had some effect but unlikely much more than that lost by cosmic rays over the same period of time. Holding an aged EPROM about 2 inches from a florescent lamp is still not something that I'd bet on. Dwight From: D. Resor Sent: Tuesday, March 22, 2022 2:40 AM To: 'dwight' ; 'General Discussion: On-Topic and Off-Topic Posts' Subject: RE: ID UV erasable PROMS used on an IBM PC board? There are a few other problems. The power supply does not power up. Three of it’s four voltages are missing (+5vdc, +8.5vdc, +13vdc). With no connections to the power supply board, the +5vdc measures 4.92vdc while the other two voltages are still zero volts. The second issue I found upon removing the driver and processor board is moisture had entered the typewriter’s electronics and the connector between the two boards has corrosion on many of the pins and on the PWB near the connector. I do not have access to a microscope. I know it has been explained to me elsewhere that UV exposure from florescent lamps can erase the proms. The way I understand is the glass of the florescent lamp filters out any UV radiation (as does the piece of glass mounted in front of quartz halogen lighting). In order that a UV lamp can operate correctly the tube must be made of quartz, not glass. Am I wrong here? Don Resor From: dwight Sent: Monday, March 21, 2022 4:50 PM To: 'General Discussion: On-Topic and Off-Topic Posts' ; D. Resor Subject: Re: ID UV erasable PROMS used on an IBM PC board? The dies look to have consistent wire bonding. That would mean they are one of the standard EPROMs made by Intel, just preprogrammed by Intel before shipping. The numbers wouldn't be intel numbers they would be IBMs inventory numbers. My guess is that they are 2732s. You might use a microscope and look at the edges of the dies. They often have the die type in the metal layers around the edge some place. Avoid using florescent ring lights as a large amount of UVC leaks from these. White LED are or incandescent lights. Also power it up and note which pins look to have signals. if any of the lines have what looks like a constant voltage measure it to the nearest .01 volts if you can. That will help determine if it is driven by a signal or a hard tied wire. Lower left and upper right should be ground and power pins. Dwight From: cctalk on behalf of D. Resor via cctalk Sent: Sunday, March 20, 2022 6:53 PM To: 'General Discussion: On-Topic and Off-Topic Posts' Subject: ID UV erasable PROMS used on an IBM PC board? I cannot find a datasheet by any of the numbers silkscreened on these ICs. Could these be proprietary IBM P/N numbers? https://www.dropbox.com/s/f6rvemx9ldbbv5x/EPROMS1.jpg?dl=0 No need for a Dropbox account, close the login pop up and you can view the image. Thanks Don Resor
Re: ID UV erasable PROMS used on an IBM PC board?
You are correct ordinary glass does not transmit UV well, the UV lamps normally used to erase EPROMs and germicidal lamps like the window in an EPROM are made from quartz glass. Florescent lights do leak a little UV but it would take a long time to erase an EPROM. Paul. On 2022-03-22 06:40, D. Resor via cctalk wrote: There are a few other problems. The power supply does not power up. Three of it's four voltages are missing (+5vdc, +8.5vdc, +13vdc). With no connections to the power supply board, the +5vdc measures 4.92vdc while the other two voltages are still zero volts. The second issue I found upon removing the driver and processor board is moisture had entered the typewriter's electronics and the connector between the two boards has corrosion on many of the pins and on the PWB near the connector. I do not have access to a microscope. I know it has been explained to me elsewhere that UV exposure from florescent lamps can erase the proms. The way I understand is the glass of the florescent lamp filters out any UV radiation (as does the piece of glass mounted in front of quartz halogen lighting). In order that a UV lamp can operate correctly the tube must be made of quartz, not glass. Am I wrong here? Don Resor From: dwight Sent: Monday, March 21, 2022 4:50 PM To: 'General Discussion: On-Topic and Off-Topic Posts' ; D. Resor Subject: Re: ID UV erasable PROMS used on an IBM PC board? The dies look to have consistent wire bonding. That would mean they are one of the standard EPROMs made by Intel, just preprogrammed by Intel before shipping. The numbers wouldn't be intel numbers they would be IBMs inventory numbers. My guess is that they are 2732s. You might use a microscope and look at the edges of the dies. They often have the die type in the metal layers around the edge some place. Avoid using florescent ring lights as a large amount of UVC leaks from these. White LED are or incandescent lights. Also power it up and note which pins look to have signals. if any of the lines have what looks like a constant voltage measure it to the nearest .01 volts if you can. That will help determine if it is driven by a signal or a hard tied wire. Lower left and upper right should be ground and power pins. Dwight _ From: cctalk on behalf of D. Resor via cctalk Sent: Sunday, March 20, 2022 6:53 PM To: 'General Discussion: On-Topic and Off-Topic Posts' Subject: ID UV erasable PROMS used on an IBM PC board? I cannot find a datasheet by any of the numbers silkscreened on these ICs. Could these be proprietary IBM P/N numbers? https://www.dropbox.com/s/f6rvemx9ldbbv5x/EPROMS1.jpg?dl=0 No need for a Dropbox account, close the login pop up and you can view the image. Thanks Don Resor
RE: ID UV erasable PROMS used on an IBM PC board?
There are a few other problems. The power supply does not power up. Three of it's four voltages are missing (+5vdc, +8.5vdc, +13vdc). With no connections to the power supply board, the +5vdc measures 4.92vdc while the other two voltages are still zero volts. The second issue I found upon removing the driver and processor board is moisture had entered the typewriter's electronics and the connector between the two boards has corrosion on many of the pins and on the PWB near the connector. I do not have access to a microscope. I know it has been explained to me elsewhere that UV exposure from florescent lamps can erase the proms. The way I understand is the glass of the florescent lamp filters out any UV radiation (as does the piece of glass mounted in front of quartz halogen lighting). In order that a UV lamp can operate correctly the tube must be made of quartz, not glass. Am I wrong here? Don Resor From: dwight Sent: Monday, March 21, 2022 4:50 PM To: 'General Discussion: On-Topic and Off-Topic Posts' ; D. Resor Subject: Re: ID UV erasable PROMS used on an IBM PC board? The dies look to have consistent wire bonding. That would mean they are one of the standard EPROMs made by Intel, just preprogrammed by Intel before shipping. The numbers wouldn't be intel numbers they would be IBMs inventory numbers. My guess is that they are 2732s. You might use a microscope and look at the edges of the dies. They often have the die type in the metal layers around the edge some place. Avoid using florescent ring lights as a large amount of UVC leaks from these. White LED are or incandescent lights. Also power it up and note which pins look to have signals. if any of the lines have what looks like a constant voltage measure it to the nearest .01 volts if you can. That will help determine if it is driven by a signal or a hard tied wire. Lower left and upper right should be ground and power pins. Dwight _ From: cctalk on behalf of D. Resor via cctalk Sent: Sunday, March 20, 2022 6:53 PM To: 'General Discussion: On-Topic and Off-Topic Posts' Subject: ID UV erasable PROMS used on an IBM PC board? I cannot find a datasheet by any of the numbers silkscreened on these ICs. Could these be proprietary IBM P/N numbers? https://www.dropbox.com/s/f6rvemx9ldbbv5x/EPROMS1.jpg?dl=0 No need for a Dropbox account, close the login pop up and you can view the image. Thanks Don Resor
Re: ID UV erasable PROMS used on an IBM PC board?
The only new information I can gather from those picture is it would appear that pins 1 and 28 of the EPROMs is tied together and since 28 is Vcc, connected to +5V this would eliminate 27512 as pin 1 on a 27512 is A15, but on 2764, 27128, and 27256 it is Vpp and would normally be tied to +5V for read. As I mentioned previously the empty position has pin 26, 27, and 28 tied together, if the positions that are populated with sockets are the same that would eliminate 27128 and 27256 as well, and I would stand by my previous suggestion that it is 2764. I would suggest that you check to see if 26 and 27 are connected to pin 28 on those sockets to verify. Paul. On 2022-03-22 07:03, D. Resor via cctalk wrote: 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. https://www.dropbox.com/s/juvn0ahnwp51k80/ProcessorPWBCompSide1.jpg?dl=0 https://www.dropbox.com/s/s4mqpxd9ksnciil/ProcessorPWBSolderSide1.jpg?dl=0 https://www.dropbox.com/s/rl26dkv3jjuip0u/PromUnderside1.jpg?dl=0 https://www.dropbox.com/s/mqok0avoqqumyuq/PowerSpplyPWB1.jpg?dl=0 Don Resor -Original Message- From: cctalk On Behalf Of Glen Slick via cctalk Sent: Monday, March 21, 2022 9:17 PM To: General Discussion: On-Topic and Off-Topic Posts 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 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
RE: ID UV erasable PROMS used on an IBM PC board?
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. https://www.dropbox.com/s/juvn0ahnwp51k80/ProcessorPWBCompSide1.jpg?dl=0 https://www.dropbox.com/s/s4mqpxd9ksnciil/ProcessorPWBSolderSide1.jpg?dl=0 https://www.dropbox.com/s/rl26dkv3jjuip0u/PromUnderside1.jpg?dl=0 https://www.dropbox.com/s/mqok0avoqqumyuq/PowerSpplyPWB1.jpg?dl=0 Don Resor -Original Message- From: cctalk On Behalf Of Glen Slick via cctalk Sent: Monday, March 21, 2022 9:17 PM To: General Discussion: On-Topic and Off-Topic Posts 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 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
Re: ID UV erasable PROMS used on an IBM PC board?
On Mon, Mar 21, 2022 at 8:25 PM Chuck Guzis via cctalk 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
Re: ID UV erasable PROMS used on an IBM PC board?
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. I suppose one could find representative known Intel samples and compare the appearance "under the window", but I've never done that. --Chuck
Re: ID UV erasable PROMS used on an IBM PC board?
Yes, you are correct. I'm a bad counter. I knew a 2732 was a 24 but suffer from brain rot. Still it is likely a standard Intel part. At most it may have a pin swap on something like a select pin. Measuring the pins, will tell which pins are tied and which are active. Dwight From: cctalk on behalf of Paul Berger via cctalk Sent: Monday, March 21, 2022 5:19 PM To: dwight via cctalk Subject: Re: ID UV erasable PROMS used on an IBM PC board? They won't be 2732 as the EPROM in the picture has 28 pins, but 2732 is a 24 pin package 2764, 27128, 27256 and 27512 are all in 28 pin packages. The 8519602 does look like an IBM house number but unfortunately it is not listed in the cross reference I have . I would agree it should be fairly easy to figure out what they are by looking at the circuitry surrounding them. The unpopulated U3 position beside the EPROM looks like it might be for another EPROM and it looks to have pins 26,27,and 28 all tied together on everything larger than a 2764, pin 26 is A13 so my guess would be 2764. If you read a 2764 as a 27128 the upper and lower halves of the image will be identical because the A13 pin is not connected on a 2764 so you would effectively read the EPROM twice. Pin 26 tied high would eliminate anything larger than a 2764. Paul. On 2022-03-21 20:49, dwight via cctalk wrote: > The dies look to have consistent wire bonding. That would mean they are one > of the standard EPROMs made by Intel, just preprogrammed by Intel before > shipping. The numbers wouldn't be intel numbers they would be IBMs inventory > numbers. My guess is that they are 2732s. You might use a microscope and look > at the edges of the dies. They often have the die type in the metal layers > around the edge some place. Avoid using florescent ring lights as a large > amount of UVC leaks from these. White LED are or incandescent lights. > Also power it up and note which pins look to have signals. if any of the > lines have what looks like a constant voltage measure it to the nearest .01 > volts if you can. That will help determine if it is driven by a signal or a > hard tied wire. Lower left and upper right should be ground and power pins. > Dwight > > > > From: cctalk on behalf of D. Resor via cctalk > > Sent: Sunday, March 20, 2022 6:53 PM > To: 'General Discussion: On-Topic and Off-Topic Posts' > Subject: ID UV erasable PROMS used on an IBM PC board? > > I cannot find a datasheet by any of the numbers silkscreened on these ICs. > > Could these be proprietary IBM P/N numbers? > > https://www.dropbox.com/s/f6rvemx9ldbbv5x/EPROMS1.jpg?dl=0 > > No need for a Dropbox account, close the login pop up and you can view the > image. > > Thanks > > Don Resor > >
Re: ID UV erasable PROMS used on an IBM PC board?
They won't be 2732 as the EPROM in the picture has 28 pins, but 2732 is a 24 pin package 2764, 27128, 27256 and 27512 are all in 28 pin packages. The 8519602 does look like an IBM house number but unfortunately it is not listed in the cross reference I have . I would agree it should be fairly easy to figure out what they are by looking at the circuitry surrounding them. The unpopulated U3 position beside the EPROM looks like it might be for another EPROM and it looks to have pins 26,27,and 28 all tied together on everything larger than a 2764, pin 26 is A13 so my guess would be 2764. If you read a 2764 as a 27128 the upper and lower halves of the image will be identical because the A13 pin is not connected on a 2764 so you would effectively read the EPROM twice. Pin 26 tied high would eliminate anything larger than a 2764. Paul. On 2022-03-21 20:49, dwight via cctalk wrote: The dies look to have consistent wire bonding. That would mean they are one of the standard EPROMs made by Intel, just preprogrammed by Intel before shipping. The numbers wouldn't be intel numbers they would be IBMs inventory numbers. My guess is that they are 2732s. You might use a microscope and look at the edges of the dies. They often have the die type in the metal layers around the edge some place. Avoid using florescent ring lights as a large amount of UVC leaks from these. White LED are or incandescent lights. Also power it up and note which pins look to have signals. if any of the lines have what looks like a constant voltage measure it to the nearest .01 volts if you can. That will help determine if it is driven by a signal or a hard tied wire. Lower left and upper right should be ground and power pins. Dwight From: cctalk on behalf of D. Resor via cctalk Sent: Sunday, March 20, 2022 6:53 PM To: 'General Discussion: On-Topic and Off-Topic Posts' Subject: ID UV erasable PROMS used on an IBM PC board? I cannot find a datasheet by any of the numbers silkscreened on these ICs. Could these be proprietary IBM P/N numbers? https://www.dropbox.com/s/f6rvemx9ldbbv5x/EPROMS1.jpg?dl=0 No need for a Dropbox account, close the login pop up and you can view the image. Thanks Don Resor
Re: ID UV erasable PROMS used on an IBM PC board?
The dies look to have consistent wire bonding. That would mean they are one of the standard EPROMs made by Intel, just preprogrammed by Intel before shipping. The numbers wouldn't be intel numbers they would be IBMs inventory numbers. My guess is that they are 2732s. You might use a microscope and look at the edges of the dies. They often have the die type in the metal layers around the edge some place. Avoid using florescent ring lights as a large amount of UVC leaks from these. White LED are or incandescent lights. Also power it up and note which pins look to have signals. if any of the lines have what looks like a constant voltage measure it to the nearest .01 volts if you can. That will help determine if it is driven by a signal or a hard tied wire. Lower left and upper right should be ground and power pins. Dwight From: cctalk on behalf of D. Resor via cctalk Sent: Sunday, March 20, 2022 6:53 PM To: 'General Discussion: On-Topic and Off-Topic Posts' Subject: ID UV erasable PROMS used on an IBM PC board? I cannot find a datasheet by any of the numbers silkscreened on these ICs. Could these be proprietary IBM P/N numbers? https://www.dropbox.com/s/f6rvemx9ldbbv5x/EPROMS1.jpg?dl=0 No need for a Dropbox account, close the login pop up and you can view the image. Thanks Don Resor
ID UV erasable PROMS used on an IBM PC board?
I cannot find a datasheet by any of the numbers silkscreened on these ICs. Could these be proprietary IBM P/N numbers? https://www.dropbox.com/s/f6rvemx9ldbbv5x/EPROMS1.jpg?dl=0 No need for a Dropbox account, close the login pop up and you can view the image. Thanks Don Resor
RE: ID UV erasable PROMS used on an IBM PC board?
This is the CPU board out of a first generation 1982-83 IBM Electronic 85 Typewriter (Electronics Driven Selectric). I was looking to archive the software/firmware from these. The machine was exposed to some dampness. Corrosion has ensued on the interface connector between the CPU and driver boards. The next year, more energy efficient memory ICs were used. Memory power failure back up only consisted of 3 AA batteries and could last up to one year. The predecessor (this board) required 6 AA size Nicads and would only retain memory for a few hours. IBM using their apparently very large stock of OLD aluminum covered ICs in as many products possible I guess. Don Resor -Original Message- From: wrco...@wrcooke.net Sent: Sunday, March 20, 2022 7:13 PM To: D. Resor Subject: Re: ID UV erasable PROMS used on an IBM PC board? > On 03/20/2022 8:59 PM D. Resor via cctalk wrote: > > > I cannot find a datasheet by any of the numbers silkscreened on these ICs. > > Could these be proprietary IBM P/N numbers? > > https://www.dropbox.com/s/f6rvemx9ldbbv5x/EPROMS1.jpg?dl=0 > > No need for a Dropbox account, close the login pop up and you can view > the image. > > Thanks > > Don Resor More details would help. What is the board? Do you know at what address in the PC memory map they fit? Based on the info you gave and the picture I would bet $1 they are standard 2764 chips. The 2764 was the first standard chip to have 28 pins. The size of the die visible through the quartz window is consistent with 2764 (as opposed to 27128 or 27256) and the fact there is room for 3 which would give 24K total. The PC didn't have a lot of places in the memory map that would allow more than 24K. Three 27128s would be 48K (a LOT in those days) and the 27256 would be 96K. I can't help with the part numbers. But I doubt they are IBM proprietary. The vast majority of chips used in the early PC line were standard from other companies. Will
Re: ID UV erasable PROMS used on an IBM PC board?
On 3/20/22 20:59, D. Resor via cctalk wrote: I cannot find a datasheet by any of the numbers silkscreened on these ICs. Could these be proprietary IBM P/N numbers? Yes, they are. But, very likely standard 27xx series of EPROMS, all you need to know are how many address bits there are and you should be able to cross-refence them to standard Intel EPROMs. https://www.dropbox.com/s/f6rvemx9ldbbv5x/EPROMS1.jpg?dl=0 Jon
ID UV erasable PROMS used on an IBM PC board?
I cannot find a datasheet by any of the numbers silkscreened on these ICs. Could these be proprietary IBM P/N numbers? https://www.dropbox.com/s/f6rvemx9ldbbv5x/EPROMS1.jpg?dl=0 No need for a Dropbox account, close the login pop up and you can view the image. Thanks Don Resor
