[solved]dead 2764 (e)proms?

[famifan]

hey there

i've found that uv eproms 2764 from my both 'Hon Shougi: Naitou 9 Dan Shougi Hiden' carts contain only zeroes.
also, i've discovered that some russian analog of 2764 (к573рф4а) from 90-91s filled by zeroes too (they came from broken zx-spectrum clone)

are they dead? will they live again after uv erasure?

let me know if anybody else has ever faced (e)prom data loss accidents

sudo cast 80sFREAK

[133MHz]

EPROMs go to all 1s when erased, so if they read all zeroes they might indeed have gone bad, assuming your dumping hardware is working properly. Can't hurt to try UV erasure on them.
I've got old EPROMs with stuck bits which won't clear away even after long UV exposure periods. Sometimes I'm able to reuse them by luck (no meaningful data goes into the bad cell areas) or by halving the usable capacity (using only the 'good half' of the chip).

[famifan]

you are right! this is the dumping hardware issue. All ICes work fine. But they are requiring #PGM set to HIGH during the reading.