Blankety blank blank.

[steve ravet]

Shannen Durphey wrote:
> 
> Well, since I've read that an ultra violet lamp can erase
> eproms, I tried it.  Set a timer for 3 mins with my lamp on
> the chip,checked it with the burner, not blank.  5 mins, 10
> mins, 20 mins; not blank.  Got to "The heck with it" and
> left it on for an hour (with six chips under it), still not
> blank.  What gives?
> 
> Lamp reads "UV-A Ultra Violet" and "BLE-270W". Wrong
> frequency?  Knowing how well my CSH fits, I made sure to
> take the stickers off the little window.  Left one in the
> sunlight for a (long) while, and it was blank when I
> checked.
> 
> Yes, I know this is crude.  Yes, I know an eraser is the
> proper way.  Yes I'm going to buy one.  In the mean time,
> why won't these chips erase?
> 
> Shannen

Shannen, anything that won't crisp your eyes won't erase chips any
faster than room light or daylight.  Even a UV "blacklight" tube doesn't
contain the frequency necessary.  UV eraser tubes have to be made of
quartz because regular glass blocks the UV frequency of interest.  The
booklet that came with my datarase explained it all very well, but it's
at home.  I think if you get a UV sterilizer tube it might work.  I've
seen 'em at Home Depot.  It will be clear, not white or purple like
regular fluorescent tubes. It should also have warnings about viewing
without eye protection all over it.  I think the wavelength of interest
is about 200 nm.  Really, if you're going to DIY be careful about
shielding it.  The Datarase with timer for $50 from Digikey is a good
deal.

--steve

--
Steve Ravet
International Meta Systems
http://www.imes.com
steve at imes.com