[John Earland]

Hi folks,
You’ve been so helpful in the past with my various projects so I hope you can help again.
I have a PET 3016 machine. It has no ROM chips so instead I use a ROM/RAM board from Tynemouth Software which works great. The PET has been working well over the past year but it has suddenly developed a new problem and has got increasingly worse. When I switch the pet on it sometimes works fine but more often I get a screen load of random characters. Sometimes when I press on the motherboard and switch it back on it works and when it does work it works really well. However, every time I switch it on at the moment I’m getting a screen full of random characters.

Previously, when it developed a fault, you were able to help me locate a problem with two of the chips which I replaced and advised me to replace the sockets of those ICs which are socketed. All of the sockets were replaced save one. It has been performing well as I say until recently when it began to run intermittently. I then decided to replace the one remaining socket but it has not resolved the issue. I can rule out ROM/RAM because I’m using the Tynemouth board. It may be a problem with my soldering of course on this last socket, the others were replaced by someone better at it than I am. As I say, when it does work it’s brilliant. It runs all software I can throw at it and I can even get on BBSs.

Any advice would be very welcome as to how I can check my soldering or the efficiency of any lines etc. I have a multi-meter and an oscilloscope (which I’m afraid to say I don’t know how to use!!).

Best wishes
John