13 Dec
2017
13 Dec
'17
6:08 a.m.
Hi,
I am working on several projects requiring 2708 and 2716 EPROMs, and
am finding some of my chips will not erase, and some will not take
a program. I've also learned more in the past week than I wanted
to know about repairing Data-I/O 29a/b programmers.
I vaguely remember in the 1990s baking such EPROMs in the oven, but
I do not remember temperature or time. I was surprised that Google
didn't turn up anything useful with this info.
I'm sure someone here will have some notes on EPROM baking.
Mark
--
Mark G. Thomas (Mark at Misty.com), KC3DRE
13 Dec
13 Dec
6:18 a.m.
On Wed, Dec 13, 2017 at 9:08 AM, Mark G Thomas via cctalk <
cctalk at classiccmp.org> wrote:
Hi,
I am working on several projects requiring 2708 and 2716 EPROMs, and
am finding some of my chips will not erase, and some will not take
a program. I've also learned more in the past week than I wanted
to know about repairing Data-I/O 29a/b programmers.
I vaguely remember in the 1990s baking such EPROMs in the oven, but
I do not remember temperature or time. I was surprised that Google
didn't turn up anything useful with this info.
I'm sure someone here will have some notes on EPROM baking.
Mark
Mark,
If this is an issue about reviving bad eproms? I assume you have tried the
regular stuff.
What process are you using now to erase 2708/16's? I have a simple eraser
unit and it seems to always work. Some eproms go bad but I never have
issues with erasing them. My point is that maybe you need a better prom
eraser unit. I would avoid baking them until you have exhausted other
options. Not sure what others think. This topic has come up before here,
about putting them outside and all that. The erasers are all over ebay,
and the hardware store is full of the correct types of lighting, why not
make a box that will do the job? I assume there is more to it that
simply erasing them.
Bill
6:49 a.m.
When I was at Intel, years ago, I recall the baking was only to repair the retention of
the EPROMs. It was not to fix random failures.
It sounds like your EPROMs have various failures that wouldn't be helped by baking.
Each time the EPROM is programmed, there is a slight increase in the leakage of the
floating gate. This was typical after thousands of program/erase cycles. Baking them
repaired the damage to the insulating layer that was damaged.
Dwight
________________________________
From: cctalk <cctalk-bounces at classiccmp.org> on behalf of william degnan via
cctalk <cctalk at classiccmp.org>
Sent: Wednesday, December 13, 2017 6:18:16 AM
To: Mark G Thomas; General Discussion: On-Topic and Off-Topic Posts
Subject: Re: EPROM baking
On Wed, Dec 13, 2017 at 9:08 AM, Mark G Thomas via cctalk <
cctalk at classiccmp.org> wrote:
Hi,
I am working on several projects requiring 2708 and 2716 EPROMs, and
am finding some of my chips will not erase, and some will not take
a program. I've also learned more in the past week than I wanted
to know about repairing Data-I/O 29a/b programmers.
I vaguely remember in the 1990s baking such EPROMs in the oven, but
I do not remember temperature or time. I was surprised that Google
didn't turn up anything useful with this info.
I'm sure someone here will have some notes on EPROM baking.
Mark
Mark,
If this is an issue about reviving bad eproms? I assume you have tried the
regular stuff.
What process are you using now to erase 2708/16's? I have a simple eraser
unit and it seems to always work. Some eproms go bad but I never have
issues with erasing them. My point is that maybe you need a better prom
eraser unit. I would avoid baking them until you have exhausted other
options. Not sure what others think. This topic has come up before here,
about putting them outside and all that. The erasers are all over ebay,
and the hardware store is full of the correct types of lighting, why not
make a box that will do the job? I assume there is more to it that
simply erasing them.
Bill
7:17 a.m.
Hmm..I've read about that baking in conjunction with 1702A too..but
don't remember the source of that discussion. I know that ppl suggested
it for proms that would'nt program correctly...
Regards,
Holm
dwight via cctalk wrote:
When I was at Intel, years ago, I recall the baking
was only to repair the retention of the EPROMs. It was not to fix random failures.
It sounds like your EPROMs have various failures that wouldn't be helped by baking.
Each time the EPROM is programmed, there is a slight increase in the leakage of the
floating gate. This was typical after thousands of program/erase cycles. Baking them
repaired the damage to the insulating layer that was damaged.
Dwight
________________________________
From: cctalk <cctalk-bounces at classiccmp.org> on behalf of william degnan via
cctalk <cctalk at classiccmp.org>
Sent: Wednesday, December 13, 2017 6:18:16 AM
To: Mark G Thomas; General Discussion: On-Topic and Off-Topic Posts
Subject: Re: EPROM baking
On Wed, Dec 13, 2017 at 9:08 AM, Mark G Thomas via cctalk <
cctalk at classiccmp.org> wrote:
--
Technik Service u. Handel Tiffe, www.tsht.de, Holm Tiffe,
Freiberger Stra?e 42, 09600 Obersch?na, USt-Id: DE253710583
info at tsht.de Fax +49 3731 74200 Tel +49 3731 74222 Mobil: 0172 8790 741
Hi,
I am working on several projects requiring 2708 and 2716 EPROMs, and
am finding some of my chips will not erase, and some will not take
a program. I've also learned more in the past week than I wanted
to know about repairing Data-I/O 29a/b programmers.
I vaguely remember in the 1990s baking such EPROMs in the oven, but
I do not remember temperature or time. I was surprised that Google
didn't turn up anything useful with this info.
I'm sure someone here will have some notes on EPROM baking.
Mark
Mark,
If this is an issue about reviving bad eproms? I assume you have tried the
regular stuff.
What process are you using now to erase 2708/16's? I have a simple eraser
unit and it seems to always work. Some eproms go bad but I never have
issues with erasing them. My point is that maybe you need a better prom
eraser unit. I would avoid baking them until you have exhausted other
options. Not sure what others think. This topic has come up before here,
about putting them outside and all that. The erasers are all over ebay,
and the hardware store is full of the correct types of lighting, why not
make a box that will do the job? I assume there is more to it that
simply erasing them.
Bill 
7:33 a.m.
My homemade 8080 CPM machine used a number of 2708 and 2716 EPROMs. that was 40 years ago.
This machine is still running and I use it, but since I had trouble with the EPROMs, I
switched to EEPROMs. I would also be interested in hearing about whether or not baking
would work and how to do the baking, exactly. I have a bunch of old EPROMs, that I figured
were dead, but maybe not??Mike Zahorik
From: Holm Tiffe via cctalk <cctalk at classiccmp.org>
To: dwight via cctalk <cctalk at classiccmp.org>
Sent: Wednesday, December 13, 2017 9:17 AM
Subject: Re: EPROM baking
Hmm..I've read about that baking in conjunction with 1702A too..but
don't remember the source of that discussion. I know that ppl suggested
it for proms that would'nt program correctly...
Regards,
Holm
dwight via cctalk wrote:
When I was at Intel, years ago, I recall the baking
was only to repair the retention of the EPROMs. It was not to fix random failures.
It sounds like your EPROMs have various failures that wouldn't be helped by baking.
Each time the EPROM is programmed, there is a slight increase in the leakage of the
floating gate. This was typical after thousands of program/erase cycles. Baking them
repaired the damage to the insulating layer that was damaged.
Dwight
________________________________
From: cctalk <cctalk-bounces at classiccmp.org> on behalf of william degnan via
cctalk <cctalk at classiccmp.org>
Sent: Wednesday, December 13, 2017 6:18:16 AM
To: Mark G Thomas; General Discussion: On-Topic and Off-Topic Posts
Subject: Re: EPROM baking
On Wed, Dec 13, 2017 at 9:08 AM, Mark G Thomas via cctalk <
cctalk at classiccmp.org> wrote:
--
? ? ? Technik Service u. Handel Tiffe, www.tsht.de, Holm Tiffe,
? ? Freiberger Stra?e 42, 09600 Obersch?na, USt-Id: DE253710583
info at tsht.de Fax +49 3731 74200 Tel +49 3731 74222 Mobil: 0172 8790 741
Hi,
I am working on several projects requiring 2708 and 2716 EPROMs, and
am finding some of my chips will not erase, and some will not take
a program. I've also learned more in the past week than I wanted
to know about repairing Data-I/O 29a/b programmers.
I vaguely remember in the 1990s baking such EPROMs in the oven, but
I do not remember temperature or time. I was surprised that Google
didn't turn up anything useful with this info.
I'm sure someone here will have some notes on EPROM baking.
Mark
Mark,
If this is an issue about reviving bad eproms?? I assume you have tried the
regular stuff.
What process are you using now to erase 2708/16's?? I have a simple eraser
unit and it seems to always work.? Some eproms go bad but I never have
issues with erasing them.? My point is that maybe you need a better prom
eraser unit.? I would avoid baking them until you have exhausted other
options.? Not sure what others think.? This topic has come up before here,
about putting them outside and all that.? The erasers are all over ebay,
and the hardware store is full of the correct types of lighting, why not
make a box that will do the job?? ? I assume there is more to it that
simply erasing them.
Bill 
9:18 a.m.
The only "baking" I've heard about with EPROMs was *annealing* on the
original prototypes from Intel. I want to say that was before they figured
out UV erasure and were zapping the things with X-rays for erasure. You
won't be doing any EPROM annealing in a home oven :)
It's been my experience that usually defective 2708s or 2716s will fail to
program, rather than fail to erase. Be aware that some of these old EPROMs
take quite a while to erase. Newer stuff like 2764s are usually done in
around 15 minutes with my old UV eraser, but I've had to run old 2708s and
1702s for much longer, 30+ minutes usually. I think my eraser uses a 15W
lamp, for reference.
Try programming all zeros and see if it'll take. If it does, try and erase
them. If you start seeing some bits flip to one but not all of them,
increase exposure time. If you get up around an hour and you still have
zeros in some positions, the EPROM is likely bad. If you're debugging or
developing on something, I wouldn't bother messing around with potentially
bad EPROMs, especially 2716s since those are still pretty available. You
can also drop a 2816 EEPROM in there (there are other pin-compatible
EEPROMs, SEEQ had one, there may be others).
And, of course, be aware that Texas Instruments' 2716 is its own thing and
not compatible with the common 5V-only 2716s. They called their Intel 2716
compatible a 2516.
Thanks,
Jonathan
On Wed, Dec 13, 2017 at 10:33 AM, Michael Zahorik via cctalk <
cctalk at classiccmp.org> wrote:
My homemade 8080 CPM machine used a number of 2708 and
2716 EPROMs. that
was 40 years ago. This machine is still running and I use it, but since I
had trouble with the EPROMs, I switched to EEPROMs. I would also be
interested in hearing about whether or not baking would work and how to do
the baking, exactly. I have a bunch of old EPROMs, that I figured were
dead, but maybe not? Mike Zahorik
From: Holm Tiffe via cctalk <cctalk at classiccmp.org>
To: dwight via cctalk <cctalk at classiccmp.org>
Sent: Wednesday, December 13, 2017 9:17 AM
Subject: Re: EPROM baking
Hmm..I've read about that baking in conjunction with 1702A too..but
don't remember the source of that discussion. I know that ppl suggested
it for proms that would'nt program correctly...
Regards,
Holm
dwight via cctalk wrote:
When I was at Intel, years ago, I recall the
baking was only to repair
the retention of the EPROMs. It was not to fix random
failures.
It sounds like your EPROMs have various failures that wouldn't be helped
by
baking.
Each time the EPROM is programmed, there is a slight increase in the
leakage of
the floating gate. This was typical after thousands of
program/erase cycles. Baking them repaired the damage to the insulating
layer that was damaged.
Dwight
________________________________
From: cctalk <cctalk-bounces at classiccmp.org> on behalf of william
degnan
via cctalk <cctalk at classiccmp.org>
Sent: Wednesday, December 13, 2017 6:18:16 AM
To: Mark G Thomas; General Discussion: On-Topic and Off-Topic Posts
Subject: Re: EPROM baking
On Wed, Dec 13, 2017 at 9:08 AM, Mark G Thomas via cctalk <
cctalk at classiccmp.org> wrote:
the
Hi,
I am working on several projects requiring 2708 and 2716 EPROMs, and
am finding some of my chips will not erase, and some will not take
a program. I've also learned more in the past week than I wanted
to know about repairing Data-I/O 29a/b programmers.
I vaguely remember in the 1990s baking such EPROMs in the oven, but
I do not remember temperature or time. I was surprised that Google
didn't turn up anything useful with this info.
I'm sure someone here will have some notes on EPROM baking.
Mark
Mark,
If this is an issue about reviving bad eproms? I assume you have tried regular stuff.
What process are you using now to erase 2708/16's? I have a simple
eraser
unit and it seems to always work. Some eproms go
bad but I never have
issues with erasing them. My point is that maybe you need a better prom
eraser unit. I would avoid baking them until you have exhausted other
options. Not sure what others think. This topic has come up before
here,
about putting them outside and all that. The
erasers are all over ebay,
and the hardware store is full of the correct types of lighting, why not
make a box that will do the job? I assume there is more to it that
simply erasing them.
Bill
--
Technik Service u. Handel Tiffe, www.tsht.de, Holm Tiffe,
Freiberger Stra?e 42, 09600 Obersch?na, USt-Id: DE253710583
info at tsht.de Fax +49 3731 74200 Tel +49 3731 74222 Mobil: 0172 8790 741
9:18 a.m.
Oh, and make sure the quartz window is clean :) I've had sticker residue
result in some bits not erasing.
Thanks,
Jonathan
On Wed, Dec 13, 2017 at 12:18 PM, systems_glitch <systems.glitch at gmail.com>
wrote:
The only "baking" I've heard about with
EPROMs was *annealing* on the
original prototypes from Intel. I want to say that was before they figured
out UV erasure and were zapping the things with X-rays for erasure. You
won't be doing any EPROM annealing in a home oven :)
It's been my experience that usually defective 2708s or 2716s will fail to
program, rather than fail to erase. Be aware that some of these old EPROMs
take quite a while to erase. Newer stuff like 2764s are usually done in
around 15 minutes with my old UV eraser, but I've had to run old 2708s and
1702s for much longer, 30+ minutes usually. I think my eraser uses a 15W
lamp, for reference.
Try programming all zeros and see if it'll take. If it does, try and erase
them. If you start seeing some bits flip to one but not all of them,
increase exposure time. If you get up around an hour and you still have
zeros in some positions, the EPROM is likely bad. If you're debugging or
developing on something, I wouldn't bother messing around with potentially
bad EPROMs, especially 2716s since those are still pretty available. You
can also drop a 2816 EEPROM in there (there are other pin-compatible
EEPROMs, SEEQ had one, there may be others).
And, of course, be aware that Texas Instruments' 2716 is its own thing and
not compatible with the common 5V-only 2716s. They called their Intel 2716
compatible a 2516.
Thanks,
Jonathan
On Wed, Dec 13, 2017 at 10:33 AM, Michael Zahorik via cctalk <
cctalk at classiccmp.org> wrote:
My homemade 8080 CPM machine used a number of
2708 and 2716 EPROMs. that
was 40 years ago. This machine is still running and I use it, but since I
had trouble with the EPROMs, I switched to EEPROMs. I would also be
interested in hearing about whether or not baking would work and how to do
the baking, exactly. I have a bunch of old EPROMs, that I figured were
dead, but maybe not? Mike Zahorik
From: Holm Tiffe via cctalk <cctalk at classiccmp.org>
To: dwight via cctalk <cctalk at classiccmp.org>
Sent: Wednesday, December 13, 2017 9:17 AM
Subject: Re: EPROM baking
Hmm..I've read about that baking in conjunction with 1702A too..but
don't remember the source of that discussion. I know that ppl suggested
it for proms that would'nt program correctly...
Regards,
Holm
dwight via cctalk wrote:
When I was at Intel, years ago, I recall the
baking was only to repair
the retention of the EPROMs. It was not to fix random
failures.
It sounds like your EPROMs have various failures that wouldn't be
helped by
baking.
Each time the EPROM is programmed, there is a slight increase in the
leakage of
the floating gate. This was typical after thousands of
program/erase cycles. Baking them repaired the damage to the insulating
layer that was damaged.
Dwight
________________________________
From: cctalk <cctalk-bounces at classiccmp.org> on behalf of william
degnan
via cctalk <cctalk at classiccmp.org>
Sent: Wednesday, December 13, 2017 6:18:16 AM
To: Mark G Thomas; General Discussion: On-Topic and Off-Topic Posts
Subject: Re: EPROM baking
On Wed, Dec 13, 2017 at 9:08 AM, Mark G Thomas via cctalk <
cctalk at classiccmp.org> wrote:
the
Hi,
I am working on several projects requiring 2708 and 2716 EPROMs, and
am finding some of my chips will not erase, and some will not take
a program. I've also learned more in the past week than I wanted
to know about repairing Data-I/O 29a/b programmers.
I vaguely remember in the 1990s baking such EPROMs in the oven, but
I do not remember temperature or time. I was surprised that Google
didn't turn up anything useful with this info.
I'm sure someone here will have some notes on EPROM baking.
Mark
Mark,
If this is an issue about reviving bad eproms? I assume you have tried regular stuff.
What process are you using now to erase 2708/16's? I have a simple
eraser
unit and it seems to always work. Some eproms go
bad but I never have
issues with erasing them. My point is that maybe you need a better prom
eraser unit. I would avoid baking them until you have exhausted other
options. Not sure what others think. This topic has come up before
here,
about putting them outside and all that. The
erasers are all over ebay,
and the hardware store is full of the correct types of lighting, why not
make a box that will do the job? I assume there is more to it that
simply erasing them.
Bill
--
Technik Service u. Handel Tiffe, www.tsht.de, Holm Tiffe,
Freiberger Stra?e 42, 09600 Obersch?na, USt-Id: DE253710583
info at tsht.de Fax +49 3731 74200 Tel +49 3731 74222 Mobil: 0172 8790 741
20 Dec
20 Dec
6:18 p.m.
Hi,
On Wed, Dec 13, 2017 at 9:08 AM, Mark G Thomas via
cctalk <
cctalk at classiccmp.org> wrote:
They seem to erase fine, using a PRO-LOG 9103 eraser (box, timer, tube...)
Hi,
I am working on several projects requiring 2708 and 2716 EPROMs, and
am finding some of my chips will not erase, and some will not take
a program. I've also learned more in the past week than I wanted
to know about repairing Data-I/O 29a/b programmers.
I vaguely remember in the 1990s baking such EPROMs in the oven, but
I do not remember temperature or time. I was surprised that Google
didn't turn up anything useful with this info.
I'm sure someone here will have some notes on EPROM baking.
Mark
Mark,
If this is an issue about reviving bad eproms? I assume you have tried the
regular stuff.
What process are you using now to erase 2708/16's? I have a simple eraser
unit and it seems to always work. Some eproms go bad but I never have
issues with erasing them. My point is that maybe you need a better prom
eraser unit. I would avoid baking them until you have exhausted
other
options. Not sure what others think. This topic has come up before here,
about putting them outside and all that. The erasers are all over ebay,
and the hardware store is full of the correct types of lighting, why not
make a box that will do the job? I assume there is more to it that
simply erasing them.
Bill
Erasing seems to work fine. It's the re-programming them that is the problem.
On Wed, Dec 13, 2017 at 02:49:39PM +0000, dwight via cctalk wrote:
When I was at Intel, years ago, I recall the baking
was only to repair
the retention of the EPROMs. It was not to fix random failures.
It sounds like your EPROMs have various failures that wouldn't be helped by baking.
Each time the EPROM is programmed, there is a slight increase in the leakage of the
floating gate. This was typical after thousands of program/erase cycles. Baking them
repaired the damage to the insulating layer that was damaged.
Dwight
I don't think these chips have been reprogrammed many times. It seems more
age related, affecting some brands/models in my spares but not others.
The failure mode is the chips erase successfully, but any attempt to
program them fails, and they still test blank and read back "ffff...".
Some of these were chips I erased years ago before putting in my spares
drawer, and some had fine working code on them, but I erased them to
re-program with a newer version of software on them, to discover I could not.
My stash of TI and NEC 2732s seem to have the disease, but my ST,
Mitsubishi, and several others program fine.
In the case of a bunch of 2732s, I have tried both a vintage DataI/O 29A
programmer and a modern Batronix programmer, with the same results.
I don't think I have a programmer problem.
I still swear someone in the late 80's had me baking EPROMs in an oven
to restore their programability, but I don't remember the specifics. I
tried a few at 450F for 15 minutes, but they still won't program.
Mark
--
Mark G. Thomas (Mark at Misty.com), KC3DRE
21 Dec
21 Dec
7:05 a.m.
Hi,
Are you positive you have the programming voltage right? I have a box of
really old ones and every time I have to research a little to find the
right voltage for different brands. All 27128's are not the same, for
example. Some are 12V, some may be 25V (for example). My programmer only
has one setting in the software, and I have to change jumpers to modify
programming voltage. My USB programmer won't touch any of the old ones
because I assume it can't provide enough voltage/current for them.
-Pete Rittwage
On Wed, Dec 13, 2017 at 9:08 AM, Mark G Thomas
via cctalk <
cctalk at classiccmp.org> wrote:
They seem to erase fine, using a PRO-LOG 9103 eraser (box, timer, tube...)
Hi,
I am working on several projects requiring 2708 and 2716 EPROMs, and
am finding some of my chips will not erase, and some will not take
a program. I've also learned more in the past week than I wanted
to know about repairing Data-I/O 29a/b programmers.
I vaguely remember in the 1990s baking such EPROMs in the oven, but
I do not remember temperature or time. I was surprised that Google
didn't turn up anything useful with this info.
I'm sure someone here will have some notes on EPROM baking.
Mark
Mark,
If this is an issue about reviving bad eproms? I assume you have tried
the
regular stuff.
What process are you using now to erase 2708/16's? I have a simple
eraser
unit and it seems to always work. Some eproms go bad but I never have
issues with erasing them. My point is that maybe you need a better prom
eraser unit. I would avoid baking them until you have
exhausted other
options. Not sure what others think. This topic has come up before
here,
about putting them outside and all that. The erasers are all over ebay,
and the hardware store is full of the correct types of lighting, why not
make a box that will do the job? I assume there is more to it that
simply erasing them.
Bill
Erasing seems to work fine. It's the re-programming them that is the
problem.
On Wed, Dec 13, 2017 at 02:49:39PM +0000, dwight via cctalk wrote:
When I was at Intel, years ago, I recall the
baking was only to repair
the retention of the EPROMs. It was not to fix random failures.
It sounds like your EPROMs have various failures that wouldn't be helped
by baking.
Each time the EPROM is programmed, there is a slight increase in the
leakage of the floating gate. This was typical after thousands of
program/erase cycles. Baking them repaired the damage to the insulating
layer that was damaged.
Dwight
I don't think these chips have been reprogrammed many times. It seems more
age related, affecting some brands/models in my spares but not others.
The failure mode is the chips erase successfully, but any attempt to
program them fails, and they still test blank and read back "ffff...".
Some of these were chips I erased years ago before putting in my spares
drawer, and some had fine working code on them, but I erased them to
re-program with a newer version of software on them, to discover I could
not.
My stash of TI and NEC 2732s seem to have the disease, but my ST,
Mitsubishi, and several others program fine.
In the case of a bunch of 2732s, I have tried both a vintage DataI/O 29A
programmer and a modern Batronix programmer, with the same results.
I don't think I have a programmer problem.
I still swear someone in the late 80's had me baking EPROMs in an oven
to restore their programability, but I don't remember the specifics. I
tried a few at 450F for 15 minutes, but they still won't program.
9:34 a.m.
If you've over voltages them, they are history.
If the ground pin is not making good contact and you try to program them, they will also
be history.
Dwight
________________________________
From: cctalk <cctalk-bounces at classiccmp.org> on behalf of Pete Rittwage via
cctalk <cctalk at classiccmp.org>
Sent: Thursday, December 21, 2017 7:05:06 AM
To: Mark G Thomas; General Discussion: On-Topic Posts
Cc: cctalk at classiccmp.org
Subject: Re: EPROM baking
Hi,
Are you positive you have the programming voltage right? I have a box of
really old ones and every time I have to research a little to find the
right voltage for different brands. All 27128's are not the same, for
example. Some are 12V, some may be 25V (for example). My programmer only
has one setting in the software, and I have to change jumpers to modify
programming voltage. My USB programmer won't touch any of the old ones
because I assume it can't provide enough voltage/current for them.
-Pete Rittwage
On Wed, Dec 13, 2017 at 9:08 AM, Mark G Thomas
via cctalk <
cctalk at classiccmp.org> wrote:
They seem to erase fine, using a PRO-LOG 9103 eraser (box, timer, tube...)
Hi,
I am working on several projects requiring 2708 and 2716 EPROMs, and
am finding some of my chips will not erase, and some will not take
a program. I've also learned more in the past week than I wanted
to know about repairing Data-I/O 29a/b programmers.
I vaguely remember in the 1990s baking such EPROMs in the oven, but
I do not remember temperature or time. I was surprised that Google
didn't turn up anything useful with this info.
I'm sure someone here will have some notes on EPROM baking.
Mark
Mark,
If this is an issue about reviving bad eproms? I assume you have tried
the
regular stuff.
What process are you using now to erase 2708/16's? I have a simple
eraser
unit and it seems to always work. Some eproms go bad but I never have
issues with erasing them. My point is that maybe you need a better prom
eraser unit. I would avoid baking them until you have
exhausted other
options. Not sure what others think. This topic has come up before
here,
about putting them outside and all that. The erasers are all over ebay,
and the hardware store is full of the correct types of lighting, why not
make a box that will do the job? I assume there is more to it that
simply erasing them.
Bill
Erasing seems to work fine. It's the re-programming them that is the
problem.
On Wed, Dec 13, 2017 at 02:49:39PM +0000, dwight via cctalk wrote:
When I was at Intel, years ago, I recall the
baking was only to repair
the retention of the EPROMs. It was not to fix random failures.
It sounds like your EPROMs have various failures that wouldn't be helped
by baking.
Each time the EPROM is programmed, there is a slight increase in the
leakage of the floating gate. This was typical after thousands of
program/erase cycles. Baking them repaired the damage to the insulating
layer that was damaged.
Dwight
I don't think these chips have been reprogrammed many times. It seems more
age related, affecting some brands/models in my spares but not others.
The failure mode is the chips erase successfully, but any attempt to
program them fails, and they still test blank and read back "ffff...".
Some of these were chips I erased years ago before putting in my spares
drawer, and some had fine working code on them, but I erased them to
re-program with a newer version of software on them, to discover I could
not.
My stash of TI and NEC 2732s seem to have the disease, but my ST,
Mitsubishi, and several others program fine.
In the case of a bunch of 2732s, I have tried both a vintage DataI/O 29A
programmer and a modern Batronix programmer, with the same results.
I don't think I have a programmer problem.
I still swear someone in the late 80's had me baking EPROMs in an oven
to restore their programability, but I don't remember the specifics. I
tried a few at 450F for 15 minutes, but they still won't program.
22 Dec
22 Dec
9:04 p.m.
I see the same things. Some chips just won't reprogram. Symptoms include failure to
program just like you, but also "chip backwards" errors. Can't remember the
chip brands, I just toss them out when that happens. I have not found any way to
resuscitate them. Maybe ~10% of the chips I tried had this, so rather frequent, but never
any from new old stock. The failed ones were all previously programmed chips, just
erased.
Marc
On Dec 20, 2017, at 6:18 PM, Mark G Thomas via cctalk <cctalk at classiccmp.org>
wrote:
My stash of TI and NEC 2732s seem to have the disease, but my ST,
Mitsubishi, and several others program fine.
In the case of a bunch of 2732s, I have tried both a vintage DataI/O 29A
programmer and a modern Batronix programmer, with the same results.
I don't think I have a programmer problem.
I still swear someone in the late 80's had me baking EPROMs in an oven
to restore their programability, but I don't remember the specifics. I
tried a few at 450F for 15 minutes, but they still won't program.
Mark
--
Mark G. Thomas (Mark at Misty.com), KC3DRE
23 Dec
23 Dec
8 a.m.
When I had access to a wire bonder, we took EPROMs that had been plugged in upside down
and removed the lids. We'd see a blown wire and replace it.
On several of these parts we found that 100% worked. So it would seem that no silicon
damage was done, just the bonding wire was blown like a fuse.
I doubt this method would repair those blown from excess programming voltage.
Dwight
________________________________
From: cctalk <cctalk-bounces at classiccmp.org> on behalf of Curious Marc via cctalk
<cctalk at classiccmp.org>
Sent: Friday, December 22, 2017 9:04:07 PM
To: Mark G Thomas; General Discussion: On-Topic and Off-Topic Posts
Subject: Re: EPROM baking
I see the same things. Some chips just won't reprogram. Symptoms include failure to
program just like you, but also "chip backwards" errors. Can't remember the
chip brands, I just toss them out when that happens. I have not found any way to
resuscitate them. Maybe ~10% of the chips I tried had this, so rather frequent, but never
any from new old stock. The failed ones were all previously programmed chips, just
erased.
Marc
On Dec 20, 2017, at 6:18 PM, Mark G Thomas via cctalk <cctalk at classiccmp.org>
wrote:
My stash of TI and NEC 2732s seem to have the disease, but my ST,
Mitsubishi, and several others program fine.
In the case of a bunch of 2732s, I have tried both a vintage DataI/O 29A
programmer and a modern Batronix programmer, with the same results.
I don't think I have a programmer problem.
I still swear someone in the late 80's had me baking EPROMs in an oven
to restore their programability, but I don't remember the specifics. I
tried a few at 450F for 15 minutes, but they still won't program.
Mark
--
Mark G. Thomas (Mark at Misty.com), KC3DRE
9:04 a.m.
On 12/23/2017 10:00 AM, dwight via cctalk wrote:
When I had access to a wire bonder, we took EPROMs
that had been plugged in upside down and removed the lids. We'd see a blown wire and
replace it.
On several of these parts we found that 100% worked. So it would seem that no silicon
damage was done, just the bonding wire was blown like a fuse.
I made my own 2716-2764 programmer MANY years ago. On a few occasions I
put an EPROM in wrong and saw the bonding wires light up! I killed
power and corrected the mistake, and the EPROM worked fine.
Jon
8:47 p.m.
On Sat, Dec 23, 2017 at 12:04 PM, Jon Elson via cctalk
<cctalk at classiccmp.org> wrote:
I made my own 2716-2764 programmer MANY years ago. On
a few occasions I put
an EPROM in wrong and saw the bonding wires light up! I killed power and
corrected the mistake, and the EPROM worked fine.
I did that once and had the same experience - a glow from under the
lid, but no smoke... and put right-way-round, was still programmable
and verifiable.
-ethan
9:16 p.m.
All chips should have windows.
On Sat, Dec 23, 2017 at 11:04 PM, Chuck Guzis via cctalk <
cctalk at classiccmp.org> wrote:
On 12/23/2017 08:47 PM, Ethan Dicks via cctalk wrote:
I did that once and had the same experience - a
glow from under the
lid, but no smoke... and put right-way-round, was still programmable
and verifiable.
Well, that's one way to "bake" an EPROM!
--Chuck
5 Feb
5 Feb
10:20 a.m.
New subject: [RESOLVED] Re: EPROM baking
Hi,
Please see resolution below, if you are curious about how this turned out.
On Wed, Dec 20, 2017 at 09:18:50PM -0500, Mark G Thomas via cctalk wrote:
Hi,
After more experimentation I came to the following conclusions.
1) Some of my chips are legitimately bad, erasing fine but won't take a program.
2) Many of the chips were failing to program because my Batronix
programmer apparently requires more current than my USB port provides.
This surprised me because I have been programming chips for years
using this programmer on this computer port successfully, and this
is the first I have had the problem. Using a Anker powered USB hub solved
things. My Batronix programmer even arrived with a cheap powered hub
when I ordered it, but I never used it because it was shipped with an
incompatible wall wart, but looking at it in the box gave me the idea
that this might be the issue.
3) I thought I had ruled out the programmer (#2) because of troubles
programming those same chips using another programmer, but I probably
had the wrong chip type selected, or simply failed on some of the #1
chips so assumed that was my only problem.
Mark
--
Mark G. Thomas (Mark at Misty.com), KC3DRE
On Wed, Dec 13, 2017 at 9:08 AM, Mark G Thomas
via cctalk <
cctalk at classiccmp.org> wrote:
They seem to erase fine, using a PRO-LOG 9103 eraser (box, timer, tube...)
> I would avoid baking them until you have exhausted other
> options. Not sure what others think. This topic has come up before here,
> about putting them outside and all that. The erasers are all over ebay,
> and the hardware store is full of the correct types of lighting, why not
> make a box that will do the job? I assume there is more to it that
> simply erasing them.
>
>
> Bill Hi,
I am working on several projects requiring 2708 and 2716 EPROMs, and
am finding some of my chips will not erase, and some will not take
a program. I've also learned more in the past week than I wanted
to know about repairing Data-I/O 29a/b programmers.
I vaguely remember in the 1990s baking such EPROMs in the oven, but
I do not remember temperature or time. I was surprised that Google
didn't turn up anything useful with this info.
I'm sure someone here will have some notes on EPROM baking.
Mark
Mark,
If this is an issue about reviving bad eproms? I assume you have tried the
regular stuff.
What process are you using now to erase 2708/16's? I have a simple eraser
unit and it seems to always work. Some eproms go bad but I never have
issues with erasing them. My point is that maybe you need a better prom
eraser unit. 
11:06 a.m.
New subject: [RESOLVED] Re: EPROM baking
On 02/05/2018 10:20 AM, Mark G Thomas via cctalk wrote:
2) Many of the chips were failing to program because
my Batronix
programmer apparently requires more current than my USB port provides.
This surprised me because I have been programming chips for years
using this programmer on this computer port successfully, and this
is the first I have had the problem. Using a Anker powered USB hub solved
things. My Batronix programmer even arrived with a cheap powered hub
when I ordered it, but I never used it because it was shipped with an
incompatible wall wart, but looking at it in the box gave me the idea
that this might be the issue.
You should be aware that many "thin" Far East USB cables will not pass
the full USB 1.5A current without substantial voltage drop. I recently
ran into this with a new LG portable DVD drive. It refused to operate,
even though I'd just taken it out of the box. I replaced the "thin"
USB cable with several other "thin" ones that I had with the same
result. Finally, in desperation, I located a "thick" USB cable, plugged
the drive in, and discovered that it worked just fine.
Moral: There's a lot of garbage out there.
Rant: The whole scheme of supplying anything but low-current using USB
is a terrible idea. I have a similar gripe with barrel connectors,
which don't seem to enforce any standard at all regarding polarity or AC
vs. DC.
For my own projects I've taken to using mini XLR connectors. Perhaps not
optimal, but they're rugged enough.
--Chuck
noon
New subject: [RESOLVED] Re: EPROM baking
My EPROM Programmers all have a connection foir external power
specifically because sometimes USB can't provide the needed current.
bill
On 02/05/2018 02:06 PM, Chuck Guzis via cctalk wrote:
On 02/05/2018 10:20 AM, Mark G Thomas via cctalk
wrote:
2) Many of the chips were failing to program
because my Batronix
programmer apparently requires more current than my USB port provides.
This surprised me because I have been programming chips for years
using this programmer on this computer port successfully, and this
is the first I have had the problem. Using a Anker powered USB hub solved
things. My Batronix programmer even arrived with a cheap powered hub
when I ordered it, but I never used it because it was shipped with an
incompatible wall wart, but looking at it in the box gave me the idea
that this might be the issue.
You should be aware that many "thin"
Far East USB cables will not pass
the full USB 1.5A current without substantial voltage drop. I recently
ran into this with a new LG portable DVD drive. It refused to operate,
even though I'd just taken it out of the box. I replaced the "thin"
USB cable with several other "thin" ones that I had with the same
result. Finally, in desperation, I located a "thick" USB cable, plugged
the drive in, and discovered that it worked just fine.
Moral: There's a lot of garbage out there.
Rant: The whole scheme of supplying anything but low-current using USB
is a terrible idea. I have a similar gripe with barrel connectors,
which don't seem to enforce any standard at all regarding polarity or AC
vs. DC.
For my own projects I've taken to using mini XLR connectors. Perhaps not
optimal, but they're rugged enough.
--Chuck
1:02 p.m.
New subject: [RESOLVED] Re: EPROM baking
On 02/05/2018 02:06 PM, Chuck Guzis via cctalk wrote:
I was going to say...I would not have thought any USB-powered prom
programmer to be the best solution. I have two programmers both have their
own wall power connectors and they're reliable. I am not saying that it
would not be possible that an USB-powered prom programmer would work, but
I'd personally want to stick with something with some legroom. I always
measure my USB supplies and cables' output to separate out the ones that
don't provide enough umph from those that do.
Happy computing
Bill
On 02/05/2018 10:20 AM, Mark G Thomas via cctalk
wrote:
> 2) Many of the chips were failing to program because my Batronix
> programmer apparently requires more current than my USB port
provides.
> This surprised me because I have been
programming chips for years
> using this programmer on this computer port successfully, and this
> is the first I have had the problem. Using a Anker powered USB hub
solved
> things. My Batronix programmer even
arrived with a cheap powered hub
> when I ordered it, but I never used it because it was shipped with
an
> incompatible wall wart, but looking at it
in the box gave me the
idea
that
this might be the issue.
You should be aware that many "thin" Far East
USB cables will not pass
the full USB 1.5A current without substantial voltage drop. I recently
ran into this with a new LG portable DVD drive. It refused to operate,
even though I'd just taken it out of the box. I replaced the "thin"
USB cable with several other "thin" ones that I had with the same
result. Finally, in desperation, I located a "thick" USB cable, plugged
the drive in, and discovered that it worked just fine.
Moral: There's a lot of garbage out there.
Rant: The whole scheme of supplying anything but low-current using USB
is a terrible idea. I have a similar gripe with barrel connectors,
which don't seem to enforce any standard at all regarding polarity or AC
vs. DC.
For my own projects I've taken to using mini XLR connectors. Perhaps not
optimal, but they're rugged enough.
--Chuck My EPROM Programmers all have a connection foir
external power
specifically because sometimes USB can't provide the needed current.
bill
4 p.m.
New subject: [RESOLVED] Re: EPROM baking
On 02/05/2018 01:02 PM, Bill Degnan via cctalk wrote:
I was going to say...I would not have thought any
USB-powered prom
programmer to be the best solution. I have two programmers both have their
own wall power connectors and they're reliable. I am not saying that it
would not be possible that an USB-powered prom programmer would work, but
I'd personally want to stick with something with some legroom. I always
measure my USB supplies and cables' output to separate out the ones that
don't provide enough umph from those that do.
Happy computing
I don't use one now, but I used to have a USB-powered programmer and it
worked okay for GALs and 27Cxxxx UV EPROMs as well as EEPROMs.
However, if I were using older parts, I'm not so sure.
The interesting thing is that upon opening the thing up, you could see
pads for a wall-wart barrel jack (unpopulated). So who knows, perhaps
Bill's USB programmer is similarly equipped.
I still use an older Xeltek Superpro for most things. It does the job.
--Chuck
4:16 p.m.
New subject: [RESOLVED] Re: EPROM baking
On 2018-02-05 8:00 PM, Chuck Guzis via cctalk wrote:
On 02/05/2018 01:02 PM, Bill Degnan via cctalk wrote:
I have a USB programmer I never use, the electronics in it where too
weak to drive NMOS EPROMs even with external power but was ok with CMOS
parts.? I have an old Xeltex Unipro and a Superpro as well as a more
mdern parallel port Xeltex superpro/280 and a Advin badged USB Xeltex
that uses external power they are all much more reliable but I have
found a couple programming algorithms for ? small AMD PLDs that are
broken.? The old Unipro came in handy when I needed to program some
bipolar PROMs.
Paul.
I was going to say...I would not have thought any
USB-powered prom
programmer to be the best solution. I have two programmers both have their
own wall power connectors and they're reliable. I am not saying that it
would not be possible that an USB-powered prom programmer would work, but
I'd personally want to stick with something with some legroom. I always
measure my USB supplies and cables' output to separate out the ones that
don't provide enough umph from those that do.
Happy computing
I don't use one now, but I used to have a USB-powered
programmer and it
worked okay for GALs and 27Cxxxx UV EPROMs as well as EEPROMs.
However, if I were using older parts, I'm not so sure.
The interesting thing is that upon opening the thing up, you could see
pads for a wall-wart barrel jack (unpopulated). So who knows, perhaps
Bill's USB programmer is similarly equipped.
I still use an older Xeltek Superpro for most things. It does the job.
--Chuck
8:56 p.m.
New subject: [RESOLVED] Re: EPROM baking
On Mon, Feb 5, 2018 at 12:06 PM, Chuck Guzis via cctalk <
cctalk at classiccmp.org> wrote:
You should be aware that many "thin" Far
East USB cables will not pass
the full USB 1.5A current without substantial voltage drop.
"Full USB current" is only 0.5A for USB 2, and 0.9A for USB 3. Any USB
device that needs more current than that should be using the Battery
Charging, Power Delivery, or Type C options, or some combination thereof,
and suitable cabling.
However, I don't disagree with your assertion that there are a lot of
really crappy USB cables out there.
6 Feb
6 Feb
9:56 a.m.
New subject: [RESOLVED] Re: EPROM baking
On Mon, Feb 05, 2018 at 11:06:29AM -0800, Chuck Guzis via cctalk wrote:
On 02/05/2018 10:20 AM, Mark G Thomas via cctalk
wrote:
Maximum current from a standard USB 2.0 port is 500 mA, USB 3.0 ups that to
900 mA. To really get some power via USB, you have to go all the way to
USB C connectors and PD (power delivery), where you easily get 65 W, at the
expense of quite bit of complexity on both ends of the cable.
Of course there are plenty of USB chargers that are all over the map - and
they usually just abuse USB cabling as power wiring, trying to cram 2 A or
more down it - which might not work if whoever made the cable "saved" a bit
too aggressively on the copper.
2) Many of the chips were failing to program
because my Batronix
programmer apparently requires more current than my USB port provides.
This surprised me because I have been programming chips for years
using this programmer on this computer port successfully, and this
is the first I have had the problem. Using a Anker powered USB hub solved
things. My Batronix programmer even arrived with a cheap powered hub
when I ordered it, but I never used it because it was shipped with an
incompatible wall wart, but looking at it in the box gave me the idea
that this might be the issue.
You should be aware that many "thin" Far East USB cables will not pass
the full USB 1.5A current without substantial voltage drop. I recently ran into this with a new LG portable DVD drive. It
refused to operate,
even though I'd just taken it out of the box. I replaced the "thin"
USB cable with several other "thin" ones that I had with the same
result. Finally, in desperation, I located a "thick" USB cable, plugged
the drive in, and discovered that it worked just fine.
Moral: There's a lot of garbage out there.
Is there ever, sadly. Including dangerous garbage - with the power levels
of USB C and PD, bad cables (and chargers) can actually by a serious fire
risk. Fortunately, Benson Leung is on a crusade against this:
https://thenextweb.com/insider/2015/11/05/a-google-engineer-is-reviewing-us…
Kind regards,
Alex.
--
"Opportunity is missed by most people because it is dressed in overalls and
looks like work." -- Thomas A. Edison
13 Dec
13 Dec
7:32 a.m.
-----Original Message-----
From: cctalk [mailto:cctalk-bounces at classiccmp.org]
On Behalf Of Mark G
Thomas via cctalk
Sent: 13 December 2017 14:09
To: CCtalk <cctalk at classiccmp.org>
Subject: EPROM baking
Hi,
I am working on several projects requiring 2708 and 2716 EPROMs, and am
finding some of my chips will not erase, and some will not take a program.
I've also learned more in the past week than I wanted to know about
repairing Data-I/O 29a/b programmers.
Any clues on resources for this. Mine seems to read but gives over current
warnings when I ask it to program ROMS..
I vaguely remember in the 1990s baking such EPROMs in
the oven, but I do
not remember temperature or time. I was surprised that Google didn't turn
up anything useful with this info.
I'm sure someone here will have some notes on EPROM baking.
Mark
--
Mark G. Thomas (Mark at Misty.com), KC3DRE
Dave Wade
G4UGM & EA7KAE
2511
days inactive
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days old
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