Desperado
Veteran Member
- Joined
- Nov 25, 2017
- Messages
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HighQuick, measure pin 22 of the NOP EPROM for activity before U31 pin 7 stops pulsing...
Dave
HighQuick, measure pin 22 of the NOP EPROM for activity before U31 pin 7 stops pulsing...
Dave
Now i have only U31 pin 5 and 8 LowCheck all of the output pins of U31 again - just to make sure it is only U31 pin 7 that is going LOW.
no....U31 pin 8 is 0V - that is supposed to be LOW.
Did you see U31 pin 8 mentioned in post #586?
Dave
Only 7 that is pulsing....So there is no need to measure it.
I am interested in U31 pin 7 and 9-15 ONLY.
Which of these pins are LOW/PULSING?
Dave
Is this...i probed U42 pins and i have problem with pin 7.... if i touch i have no signal and sometimes i see a flash of red light on the logic probe...What IC type is U42? Give me a chance to locate it...
Ok if there's no risk of some IC getting too hot and burning, let's continue with the tests...provided you have time and desireWhy would you assume this?
If you turn it off, you will have to get it back in this mode again tomorrow...
Your choice...
Dave
Ok Dave, we can continue tomorrow! Thanks so much Sir! Did you receveid my p.m?There is always a risk with everything...
It is getting quite late for you though isn't it - so perhaps 'call time' for tonight.
But remember, you are going to have to get the machine back in the same state again tomorrow by repeated pressing of the RESET button until (and if) you get constant activity on the CPU SYNC pin AND the NOP EPROM pin 22.
Dave