• Please review our updated Terms and Rules here

Pet 2001N horizontal line

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?
 

Attachments

  • Screenshot 2023-01-15 alle 13.27.11.png
    Screenshot 2023-01-15 alle 13.27.11.png
    41.2 KB · Views: 3
ok thanks, so are these?
 

Attachments

  • Screenshot 2023-01-15 alle 13.46.00.png
    Screenshot 2023-01-15 alle 13.46.00.png
    21.6 KB · Views: 1
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
 
Yep.

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
 
Yep.

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
I removed both 244 but tester tell me that these are ok :(
 
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.
Without any ic on e9 socket i can t see square waveform signal but i see always the strange noise signal :(
 
This is actually ram jumpers setting... Maybe wrong... But why??
 

Attachments

  • 1673800172655..jpg
    1673800172655..jpg
    1.1 MB · Views: 2
  • 1673800198310..jpg
    1673800198310..jpg
    1.3 MB · Views: 2
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
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?
 
Back
Top