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:
On Wed, Dec 13, 2017 at 9:08 AM, Mark G Thomas
via cctalk <
cctalk at classiccmp.org> wrote:
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.
If this is an issue about reviving bad eproms? I assume you have tried the
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
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.
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 G. Thomas (Mark at Misty.com