Problem erasing & re-using GM Proms

[Bruce Plecan]

> Have anyone been able to erase a GM prom & reprogram it?

Yes.

> I always have to solder a regular 27xxxx eprom on before I can
> re-program..  I can never seem to re-burn the factory original
> prom, which doesn't seem to have meaningful identifiers on it.
> My latest is a 27256 like thing from a '93 L35 4.3 engine.
> Could I be using the wrong programming voltage?

Yes.
Some need to bath in UV 4-6 cycles to wipe clean.
Yes, I've had some never erase.
If PCM might be 512
Bruce

> Thanks,
> Mike V

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