Re: UV Hazards and concerns

[P3D Michael Kersenbrock <michaelk@xxxxxxxxxxxxxxxxxx>]

> - When we used to work extensively with ultraviolet erasable EPROM memory
> chips (with a transparent window over the chip to allow erasure), the data
> sheets noted that the chips would be erased fairly quickly (days or weeks?)
> if kept exposed to sunlight, more slowly if exposed to room-level
> intensities of fluorescent light (months?), and far more slowly or not at all

In my experience, it didn't happen.   When EPROMS were fairly new
I tried putting the non-blocked (clear) glass window of a programmed
EPROM *FLUSH* with a fluorescent lamp (a 15W lamp as I recall).  I turned
the lamp upside down and sat the chip on the bulb (chip's legs into the air).

I left it there for weeks, running continuously (except for
an occasional outage to test the EPROM).  Nothin' happened.  Didn't
erase even a single bit of data.

But then, maybe it was just my brand of lamp (or UVEPROM).

Using a mineral-light with the heavy dark glass filter removed (which I
still have), the short-wave UV (which was needed) took little time to
erase the EPROM.

Mike K.


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