Tim Kerby wrote:
>
> I have also had this problem on two 16c74 (not 74A) chips.
> When new they took 10 mins to erase but now they take oner 1 hour.
> Microchip claim it is the eraser and the uv bulbs at #20 each need to be
> replaced every few hours.
> Personally, I think they are passing off the blame but I have found a
> solution.  I have been using an industrial turbine to blast the eraser with
> cool air while it erases, keeping the chips cool.  I had noticed that the
> chips were heating up and this gave me the idea.  My erase time is now under
> 30 mins with the same chips.  Whatever it does it certainly helps - try a
> hairdryer on cold setting, my turbine is only slightly more powerful.  I
> would be very interested to know how the devices erase - to heat generates
> by the light or by light alone.
>

I built a UV eraser with a 6W Philips tube and have used it so many
times
on a 16c71 that the paint has started to fade. I have often wondered why
people complain about the erase times for the windowed parts, but you
have
just answered that question. The light is housed in a polished
aluminimum
box and runs very cool. I have never had to wait longer than 2 minutes
for
a PIC to erase.

--
Friendly Regards

Tjaart van der Walt
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