EPROM erase times and lifespan

Dave Dunfield dave09 at dunfield.com
Thu Jan 29 10:11:49 CST 2009

> But, yeah, I guess I'll try setting the timer for longer now, to ensure they're good and blank. I
> was always told that too much UV would damage the chips - I've never left one in for more than say,
> 15 minutes before. Next time I need to erase some, I'll put 'em in for longer than three or five
> minutes...

Which is why a timer is a good thing ... I can tell you from personal experience
that forgetting a tray of EPROMs in an untimed eraser overnight leads to non-
functional devices. The ones I left in for an hour seemed to be OK, but I wouldn't
do that on a regular basis - after about the third time I left the tray in
overnight, I ripped the timer out of a dryer we were disposing of and made it an
integral part of my eraser.


PS: Since you don't know the charactistics of your lamp, I'd err on the cautious
side ...

dave09 (at)    Dave Dunfield
dunfield (dot) Firmware development services & tools: www.dunfield.com
com            Collector of vintage computing equipment:

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