Jan Beta on Nostr: nprofile1q…jvykc EPROMs are tricky, especially the used ones. For the 27C400s I ...

nprofile1qy2hwumn8ghj7un9d3shjtnyd968gmewwp6kyqpqfss6wran5c0ctm6ltxd8ney65x64k6ykz0rldwudga4k55l85y7swjvykc (nprofile…vykc) EPROMs are tricky, especially the used ones. For the 27C400s I used so far, around 20 minutes in the eraser did the trick. It may be that your EPROMs are damaged in some way or maybe your eraser is? I’d probably try to erase them with exposure to sunlight (takes a day or two) before giving up on them. But I had several batches of used EPROMs from ebay etc over the years that I didn’t get to work at all so it might also just be bad ones indeed.