8032 wrong characters ?

[dave_m]

Huh? I'm confused; isn't that exactly what I suggested? I assume that the command will work regardless of what the screen says (peek or peak); am I missing something here?

Mike,
I re-read your message #11 and I have to give you credit after all. I will never doubt you again until the next time! :D

 

[dave_m]

Well Well,, I just typed.. PRINT PEEK(32778 ) and got ..PRINP PEAK(32778 ) on the screen ( that is how the characters have changed) and still got 11 (no syntax error?)

Excellent. The problem must be in the screen refresh circuit. I'm still guessing that it will be latch UB8 or UB3. Let's think of some tests to try before unsoldering parts as unsoldering parts can damage the circuit board if too much heat is applied.
-Dave

 

[MikeS]

FWIW I did a quick analysis of the limited data with Excel and the 5 errors are always a 1 in bit 2 of an even cell getting reset if followed by a 0 in bit 2 of the next cell; no surprise, but what does it tell us? Since it's only one bit that kinda rules out a clock problem; I think I also vote for the even latch...

 

[harry]

Mike, thankyou for looking into things, I am going accept your vote, together with dave,s same thoughts about UB8 and UB3, as soon as I have replacements fitted I will give the results. ..... Harry

 

[MikeS]

Mike, thankyou for looking into things, I am going accept your vote, together with dave,s same thoughts about UB8 and UB3, as soon as I have replacements fitted I will give the results. ..... Harry

Dave's usually right and I'm usually wrong, so I figured I can't lose if I agree with him.

 

[dave_m]

Mike, thankyou for looking into things, I am going accept your vote, together with dave,s same thoughts about UB8 and UB3, as soon as I have replacements fitted I will give the results. ..... Harry

Harry,
I'm OK also with starting with the even latch UB3 first.

In case you are not experienced in removing chips:

To remove a DIP chip as safely as possible without overheating the board, sacrifice the suspect LS373 chip by cutting all 20 legs off close to the body of the chip with a small pair of diagonal cutters. With the 'body' of the chip removed, unsolder each leg one at a time. This can be done with only a short period of time with the iron at each hole to pull out each leg. After all legs are unsoldered from the board, use desoldering braid to clean up the 20 feedthrough holes of excess solder. This way you should not overheat the board and possibly damage the circuit traces. Then you can install a 20 pin socket if desired.

Hopefully you get lucky and get it right with the first chip. If not, I guess we go on with UB8.

 

[harry]

Mike, and Dave, it seems my luck , has been actually having you two guys available hear on this forum to help the likes of me! I replaced only UB3, did it work? of course it worked, everything 100% now. really pleased. many thanks for you help.
Dave, I invested in a vacuum gun desoldering station some time ago, I think one of the best tools I now have,I made some smaller nozzels to fit the gun,to avoid burning the board around the thro holes, works really good, makes chip replacement almost hassle free ( almost!!) ...... thanks again Harry

 

[dave_m]

Mike, and Dave, it seems my luck , has been actually having you two guys available hear on this forum to help the likes of me! I replaced only UB3, did it work? of course it worked, everything 100% now. really pleased. many thanks for you help.

Harry, I looked back at the messages in this thread, and it turns out in message #5, you were the first one to suggest that UB3 might be the problem.

You have done a great job in restoring the 8032 PET back to good health.

If you do not have a floppy drive or cassette for your PET, you can buy a small board from guys on this forum that plugs into the IEEE connector and uses a micro SD chip to provide memory storage to SAVE and LOAD your BASIC programs.
-Dave

 

[Babbage69]

Hi all,

Rather than start a new thread on a similar subject, I have tagged on to this one.

Recently picked up an 8032 which had similar problems to the one in this thread. Having followed the thread in lurk mode, I obtained and replaced the same parts as the OP, and have now revived another PET. Just want to thank all those who responded to and helped the OP, as this has in turn helped me. Thanks guys

Just need a listing for "Nightmare Park" now

Pat

 

[MikeS]

Harry, I looked back at the messages in this thread, and it turns out in message #5, you were the first one to suggest that UB3 might be the problem.

You have done a great job in restoring the 8032 PET back to good health.

-Dave

Well, we never disagreed, just tried to confirm and/or explore alternate possibilities without actually removing any chips, but yes indeed: great job, both Harry and Pat!!!

The rest of us are just here to learn from your experiences and maybe give you a little more confidence that you're not on your own.