unknown667 wrote:
>
> At 04:13 PM 8/13/97 -0400, Andy Kunz wrote:
> >>I've got 8 chips exhibiting this behaviour, and I tried erasing for 20 min.
> >>without success.  I'm using relatively old chips, I believe, but even with
> >>the code protection, would 20 min. be reasonable?
> >If they aren't "A" suffix parts, should be fine.  Try a longer exposure, or
> >a new bulb.  How quickly do other chips erase for you?
>
> They're 16C74A and no chips that I have work.  All I have available are
> 16C74A chips, all of which don't seem to work.  I called Microchip in
> Toronto, but they were closed at the time... probably call them tomorrow
> and ask what their opinion is.  I think the programmer's fried.
>
I've experimented with cp'd and non-cp'd 16C74A's and my decade old
Spectroline UV eraser.  Non-cp'd: 10 minutes.  Cp'd: between 1.5 and 2
hours.  I've only checked for erasure with my Picstart-16C - my Promate
II came last week and I haven't checked erased cp'd parts over the full
voltage range.  I'll be trying the same thing with 16C61's when my order
arrives.
--Matt