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How long did you give it ?well I've done it, I apparently overexposed the EPROM (27c400) by UV
lamp. (now I know there is such thing)
8 mins isn't going to break it by miles. I bet it's barely erased it.On Aug 2, 5:10 pm, Eeyore <rabbitsfriendsandrelati...@hotmail.com
wrote:
orange wrote:
well I've done it, I apparently overexposed the EPROM (27c400) by UV
lamp. (now I know there is such thing)
How long did you give it ?
Graham
I think about 4(min) (the scale is not labeled it goes from 1 to 10).
but I have exposed it twice in succession. the window was dirty and I
wasn't aware of the danger.
I think about 4(min) (the scale is not labeled it goes from 1 to 10).orange wrote:
well I've done it, I apparently overexposed the EPROM (27c400) by UV
lamp. (now I know there is such thing)
How long did you give it ?
Graham
Is the programmer reading it right ?Eeyore wrote:
orange wrote:
Eeyore wrote:
orange wrote:
well I've done it, I apparently overexposed the EPROM (27c400) by UV
lamp. (now I know there is such thing)
How long did you give it ?
Graham
I think about 4(min) (the scale is not labeled it goes from 1 to 10).
but I have exposed it twice in succession. the window was dirty and I
wasn't aware of the danger.
8 mins isn't going to break it by miles. I bet it's barely erased it.
Does it blank check ok ?
well that is the problem, its ALWAYS blank, full of FFFFFF..
it doesn't even start programming..
Home built Willem ? I've only ever used commercial programmers and had noBTW, I've got another EPROM that programs ok, but fails to verify.
strange thing is that when I read it and save it to file, that file is
the same as original, no errors. But willem still fails to verify it..
Not an especially useful site. Try a manufacturer's app note if you can stillI used 30 mins as a typical erasure time. If in doubt an hour won't hurt.
they say here to increase it every minute:
http://wiki.xtronics.com/index.php/How_EPROMS_Work#Erasing_an_EPROM
well that is the problem, its ALWAYS blank, full of FFFFFF..orange wrote:
On Aug 2, 5:10 pm, Eeyore <rabbitsfriendsandrelati...@hotmail.com
wrote:
orange wrote:
well I've done it, I apparently overexposed the EPROM (27c400) by UV
lamp. (now I know there is such thing)
How long did you give it ?
Graham
I think about 4(min) (the scale is not labeled it goes from 1 to 10).
but I have exposed it twice in succession. the window was dirty and I
wasn't aware of the danger.
8 mins isn't going to break it by miles. I bet it's barely erased it.
Does it blank check ok ?
they say here to increase it every minute:I used 30 mins as a typical erasure time. If in doubt an hour won't hurt.
Graham
p.s. if you can find a suitable programmer (see ebay) flash is SO much
better.
Oh yes, that'll kill it nicely. Early 12V Eproms only had the voltage printedfom the replies - sounds more like you may have a flakey programmer, or you
tried to program it with the wrong algorithm and put 21v on a 12.5v
programming line.
but, the thing is, I managed to program two other chips with samegcd wrote:
fom the replies - sounds more like you may have a flakey programmer, or you
tried to program it with the wrong algorithm and put 21v on a 12.5v
programming line.
Oh yes, that'll kill it nicely. Early 12V Eproms only had the voltage printed
on the package rather than a different part number.
Graham
gcd wrote:
fom the replies - sounds more like you may have a flakey programmer, or you
tried to program it with the wrong algorithm and put 21v on a 12.5v
programming line.
Oh yes, that'll kill it nicely. Early 12V Eproms only had the voltage printed
on the package rather than a different part number.
Graham
....and for some, the "A" version was the lower programming voltage part.