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CBM PET 3032 STRANGE BOOT

I replaced E9 and E10 but i have same fault... Now this:
 

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No, you don't have the same fault! Just because you get a similar error message doesn't mean that you have the same error...

Last time the error was at address 01ff (which was an invalid address report for the test itself).

This time the address and data is valid (13bb 02).

Get a few errors out of the PET (say 10 address/data pairs) and see what you observe in terms of a pattern.

Dave
 
daver2 said:
No, you don't have the same fault! Just because you get a similar error message doesn't mean that you have the same error...

Last time the error was at address 01ff (which was an invalid address report for the test itself).

This time the address and data is valid (13bb 02).

Get a few errors out of the PET (say 10 address/data pairs) and see what you observe in terms of a pattern.

Dave
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Ok but when i have this fault and i reset, when i re turn on, i have pet tester stucked on first screen...
 
Well that's interesting, PLEASE POST A PHOTOGRAPH because it may be telling us something. Don't forget to check the SYNC pin on the CPU to see if the CPU is running - and post that valuable information also.

Dave
 
Yes, when the PETTESTER sticks on the video test screen.

But, of course, you can equally compare the video screen you observe with the images in my documentation to find the differences - can't you?

Dave
 
So... These are pictures with dram fault and after i reboot the Per...
 

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If i wait some minutes and i reboot, i can see first per tester screen....
 
That screen is not the PETTESTER VDU test screen - it is just the random garbage screen.

Is/was the CPU SYNC pin toggling or not at this stage (as I asked in post #87)?

Dave
 
daver2 said:
That screen is not the PETTESTER VDU test screen - it is just the random garbage screen.

Is/was the CPU SYNC pin toggling or not at this stage (as I asked in post #87)?

Dave
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Low signal Dave :(
 
If the SYNC pin is LOW then the CPU is not executing any instructions...

When you are resetting the PET are you powering OFF, or have you attached a RESET button? I am guessing you are powering OFF - as this would give the 'random screen of rubbish'. Is this correct?

In this case (power cycling) - how long are you waiting between turning the PET OFF and then back ON again? If you turn the PET on too quick, you will not have allowed sufficient time for the capacitor in the RESET circuit to discharge, and this would explain the observed behaviour.

Dave
 
daver2 said:
If the SYNC pin is LOW then the CPU is not executing any instructions...

When you are resetting the PET are you powering OFF, or have you attached a RESET button? I am guessing you are powering OFF - as this would give the 'random screen of rubbish'. Is this correct?

In this case (power cycling) - how long are you waiting between turning the PET OFF and then back ON again? If you turn the PET on too quick, you will not have allowed sufficient time for the capacitor in the RESET circuit to discharge, and this would explain the observed behaviour.

Dave
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I haven't reset button, i turn off the PET and i waiting some seconds before to re turn on... :( MAybe bad capacitor?
 
Some seconds - define 'some'...

I generally wait for ten (10) seconds.

Why don't you install a reset button rather than blame the capacitor!

Constantly powering cycling the PET is not good - it stresses it and can cause further faults.

Dave
 
Now i solded a reset button accross C68....im waiting for the next pettester freeze....
 
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