Is there a way to wipe an EPROM that's packaged without a window?

Seeing the post on Makezine.com about opening up IC packages with a propane torch reminds me that I have a few salvaged EPROM microcontrollers and chips that were, for some reason, packaged without a window to erase them. I'm wondering, for the sake of ingenuity, if anyone knows a way to wipe these and reprogram them. I've read that x-rays might work, but I have no access to an x-ray machine.

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Probably no love on that. If there is no window, it's pretty much not an EPROM but rather a PROM (yes, they still exist for production - flash, solder, forget) or EEPROM (in which case it depends on the specs how to erase/reprogram).
frollard8 years ago
You'd need to look into the spec sheets on each part number - if it's an EPROM then its an electronically programmable rom. if it's an EEPROM then its electronically erasable programmable rom. Big difference :D If its EE then you just need to talk to it however the protocol wants. If its an old prom, it might just be a single burn and its kaput.
A bit off topic, but it makes me laugh that they call EEPROM E2PROM which makes people think it looks cooler/shorter but just takes more effort. *rolls eyes* eufff... electronic engineers eh?
There WERE One Time Programmable ROM devices, which really were EPROM devices that the makers packaged in epoxy, not expensive windowed ones.
orksecurity8 years ago
Depends on the technology. Some Programmable Read-Only Memory chips -- the earlier, cheaper (at least until recently), and more robust technology -- work by blowing "fuses" in the circuit to quite literally burn the data into them. There is no way to undo that. Odds are that this is what you're looking at. If not, there is a slight chance that these might be electrically erasable PROM (EEPROM) chips, an earlier version of the technology used in "thumb drives". See if you can find a part number and/or manufacturer on the chip, and work backward from that. But if it doesn't have a window, it isn't (intended to be) an EPROM... and I haven't heard of anyone repackaging EPROM circuits as PROM. So I think you're out of luck. Memory chips are cheap these days. Replace it?