Another PET 8032 given up on life.... any thoughts please?

[aysel]

Hi all,

My 8032sk restore has been put to one side now as my stock 8032 has now given up on me

It boots with the four/five quick chirp sounds, display is bright and clear but just shows a solid block of characters as below.



Tried so far:

• Swapped the 6502/6520 out with chips from my VIC and get same result
• Checked power supply outputs with multi meter and seem as per spec
• Removed all socketed chips, cleaned contacts and re-seated
• Cleaned full motherboard
  • visually checked traces on back and all looks to be fine

All to no avail sadly. My next plan is desolder some 2114's from a defunct VIC I have and try piggy backing them onto the PET's to see if its a RAM issue.

Just thought I would ask if anyone has had anything similar and whether the actual characters displayed have any significance or just random as they don't change from one boot to the next. Its badged as a 8096 for some reason but is actually just a stock 8032 with the single board.

Any guidance a all would be gratefully received as I am now without a working PET and that's not a nice place to be

 

[dave_m]

It boots with the four/five quick chirp sounds, display is bright and clear but just shows a solid block of characters as below.

It is hard to think that both the even RAM chips have failed the same way and both odd RAMs have also failed in another way. Or that both the odd and even latch could have failed at the same time. It may be that the Video Latch signal has failed in the low state. If you have a logic probe check for a lack of pulses at UD1-13 on sheet 8 of the schematics.

 

[aysel]

Thank you for the response Dave, much appreciated. I only have a voltmeter at the moment so I will call into Maplin on the way home from work and grab a logic probe.

I have found a beginners guide to using one so will see if I can follow your instructions without loosing my eyebrows and report back :D