[retromit]

Hi. Thanks again for the info. I haven't taken the board out yet as I didn't have a lot of time today. However, I did try the continuity testing with the pins/cathodes as suggested. Here's what I found:

- JP8 pin 4 to +ve terminal on capacitor was fine; had continuity.
- JP8 pin 2 to +ve terminal on capacitor was fine; had continuity.
- pin 2 on JP8 to left leg of CR10 and CR11 had continuity.

I measured the voltages again on all these, and they reported the low values as previously posted. I then checked continuity again, but then noticed that the screen had come on (I've attached a picture). I had been very careful when checking voltages/continuity, but was surprised to see the screen. I powered off/on the PET a couple of times and it seemed to keep bringing the screen on. So some good news. I left it for a while, then tried again; it came on but with the garbled details. I did take the voltages at this point, and they all recorded what you guggested; the big capacitor around 9v DC, CR10 and CR11 (right leg) around 5v DC.

I didn't do anything else for a while, then went back to it. Turned it on and no screen. Checked the continuity; all okay. Checked the voltages, all low.

One thing I did notice when the screen was working for a while was that UD6 and UD7 were getting quite hot to touch. I don't know if this is relevant.

So it's be a step forward (but I don't know why it sprung into life), but back to no screen working again and low voltages.

I'm hoping none of the chips have been damaged by the drop in voltage (or whatever caused it). I'm wondering if the two 2114 RAM chips I changed for the video RAM could be fried (or any other chips for that matter).

I'll have another run through of everthing tomorrow to see if anything is different, but thanks again for your help with this.