EPROM baking

[systems_glitch]

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:
>> >
>> > > 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
>>
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