EPROM Eraser not erasing New EPROM

[Randall]

Roger Heflin  wrote :
> I take it these bulbs wont last
> long and
> that's why they have a timer?

Some erasers will overheat (fire hazard) if left on for a long time, but the
primary reason for the timer is because too much erasing will 'wear out'
your EPROM.  'Worn out' EPROMs normally stay in the erased state, at least
some bits cannot be programmed.  The bulbs (at least the ones I'm familiar
with, although I haven't used UV EPROMs for many years) last a long time,
several 1000 hours at least.  They are basically just a flourescent light
bulb, without the flourescent coating and in a quartz bulb to let out the
UV.  As someone mentioned, the bulbs do lose output over time, but if the
bulb isn't visibly blackened, you shouldn't need to more than double the
exposure time.

Randall

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