Yes and no. If you read the datasheet for the EPROMs, it probably gives you a typical exposure time for erase. Erase time will increase as the UV tube ages. It also depends on the distance from the EPROM to the tube and how clean the quartz window is.I have never done a blank testing. so what do you mean?
I put the EPROM chips in a UV light eraser and set the timer to the datasheets of the EPROM chip which is about 15mins to not damage the cells. is this how you erase EPROM chips?
A "good" EPROM programmer will verify erase and program margins. I have an old Stag programmer that I confirmed doesn't perform erase margin checking correctly. I stopped using it because I wasn't sure it programmed correctly. Now I use a hobbyist programmer and I verify margins manually.
If you don't know about margins, then you don't know what you're doing and have to depend on your equipment doing it correctly. Some do, some don't. That's what my comment about all programmers not being equal meant.Maybe I'm doing something wrong about the margins. I'm not really sure how to set up the margins
Some programmers let you change timings and voltages explicitly, some don't. For the ones that don't, you have to hope that they were designed properly.The universal programmer software just has a button for reading, writing, erasing. I don't go into the settings and change anything or change the margins.
My crystal ball is at the cleaner. Even if you told me what programmer you have, I probably wouldn't know how to operate it.How Should I set it up?
I had to ask. When you were talking about EEPROMs, another poster was talking about EPROMs.Yes I know the difference, I was talking about EEPROMs at first about the read, write, checksum
If you're able to reprogram the affected EPROMs and they fail a short time afterwards, I'd question your programmer or how you're using it. A properly programmed EPROM should retain data for 10-20 years. An improperly programmed device could fail to work in the intended circuit immediately after programming. You, or your programmer, need to check erase and program margins explicitly (unless you're programming 2732 or older devices that were programmed open loop).The EPROM chips I have latency failure problems. I think the UV light eraser is the problem and the write/erase cycling is the problem of the latency failures