Desperado
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- Joined
- Nov 25, 2017
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These?We then need to monitor the data bus signals (one at a time) close to the CPU. You can't measure directly on the CPU, because these are being forced to a NOP instruction ($EA).
These?We then need to monitor the data bus signals (one at a time) close to the CPU. You can't measure directly on the CPU, because these are being forced to a NOP instruction ($EA).
No, those are the ADDRESS BUS and not the DATA BUS...These?
I removed both 244 but tester tell me that these are okYep.
I don't expect you will find a fault, but it would be good if you did...
Once you have fitted a socket for E9 and E10, do a retest without fitting replacement ICs and see if the problem has gone or not.
Dave
Without any ic on e9 socket i can t see square waveform signal but i see always the strange noise signalOnce you have fitted a socket for E9 and E10, do a retest without fitting replacement ICs and see if the problem has gone or not.
That's what I was guessing you would find...I removed both 244 but tester tell me that these are ok
Can you post another video so I can see what you are talking about please.Without any ic on e9 socket i can t see square waveform signal but i see always the strange noise signal
The links are not all for the RAM! Links R and S are not for example...This is actually ram jumpers setting... Maybe wrong... But why??
That may be the period between E800-EFFF where only a few I/O addresses will respond. A11 turns off the 2716 pettiest chip. Can Desperado check to see if that time decay and 1.5V time is around 4 mS?But I can see a strange anomaly in your video where there is an exponential decay from about 5V down to about 1V and then it holds there for a period of time before it disappears.
This strange 'imprint' shouldn't be there...
Dave