David Duffy wrote

> Mark E. Skeels wrote:
>> Dumb question: I don't suppose this eprom has a window?
>>
>> If so, did you cover it after programming?
>>
>
> Even if he didn't cover it, unless the board was under a UV light they
> won't be erased in a hurry.
> David...
>

Thanks for all the suggestions.

I was pulling them straight out of the eraser and attempting to program=20
them. No cool down time.

They had been on conductive foam in the eraser..

There are some TI and some SGS eproms.

I was covering them immediately after I programmed them, though under fluro=
=20
light I should have plenty of time to try them out first.

I burnt 60 of these exact same types a couple weeks ago with absolutely no=
=20
drama. The only thing that went wrong was a couple didn't ersase properly,=
=20
which I picked up as I started the process, so re-erased them.. Every one=20
worked without a hiccup.


Well, I went out for the evening, have come home, tried another couple=20
eproms that have had several hours cooling off after erasing, and same=20
problem.

As mentioned earlier, I'd had to reload the 'Library' because I had=20
installed a 'Serial' library to do some small eeproms since the batch of 60=
=20
x 27C256B's.

It didn't want to accept it for some time but then did, and everything else=
=20
appeared normal.

I have since reloaded the serial library to check that it would change  ..=
=20
and then back to the one for the job. Library went in ok, but still no joy.

I can put in any of the copies I've made (in the programmer) and they still=
=20
verify as the same as my original data, and the checksums are still all the=
=20
same too  ...  yet the original is the only one that works in the circuit=20
boards (I've tried a couple different boards)

If the Dataman is crook, why does the data read off all the chips ok and th=
e=20
checksum ok  ...  yet not one of the 14 I've tried have worked in it's=20
location.

Thanks for the help so far.    Roger




--=20
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