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.gli...@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@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@classiccmp.org> >> To: dwight via cctalk <cctalk@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-boun...@classiccmp.org> on behalf of william >> degnan via cctalk <cctalk@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@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 >> >> -- >> Technik Service u. Handel Tiffe, www.tsht.de, Holm Tiffe, >> Freiberger Straße 42, 09600 Oberschöna, USt-Id: DE253710583 >> i...@tsht.de Fax +49 3731 74200 Tel +49 3731 74222 Mobil: 0172 8790 741 >> >> >> >> >> >
