checked, yes RDY is high! 5V

think I did, but don't remember, will recheck, good idea.

If the data lines alone were misbehaving, I'd wonder if some device is broken, or some address decoding broken, such that you have a conflict on the bus. But with the address lines misbehaving, I'd have to think of something else. I believe the PET serves video from the main RAM, and so it must ...

I tested voltages which are good In this case it almost seems the voltage isn't reaching the CPU -- for example, as if the socket were not making a good contact. It would be a good idea to check the Vcc and Gnd voltages as measured on the actual pins of the CPU itself .

I checked VCC on the 6502 ...

Wow, that's quite a collection of machines! I had a TI-57 back in 1979 and it was a lot of fun.

thanks complimenting on my collection! I even own several of some models like the apple 2 ( 2Apple 2+ and a 2e) or commodore 64, two C64 and 1 C64-II,
2x 1541 and 1x1541-II,as for 128 I have C128D ...

I just bought a faulty PET CBM 3032. I starts with garbage collection screen and stays like this.

I tested voltages which are good, removed 6520 & 6522, and finally looked on the 6502 pins with
a 100mhz fluke scope, clock is ok coming in, and clock ph1 & ph2 signals look ok coming out.
Reset, NMI ...

Just subscribed and found this page and so introducing myself as well.

I started computer when I was 13 in 1982, first on TI57 calculators and then Sharp MZ80B computer in parallel in the junior high school computer club.
We had programming teaching by the director of the school, a computer nut ...