Quote:
Originally Posted by TonyDuell
A couple of comments...
I think all PETs used a decoder IC to select the keyboard columns. It should be easy to find by tracing the connections back from the keyboard connector, some will go to a PIA/VIA IC, the others to the decoder IC.
Secondly, a lot of problems in PETs are caused by bad IC sockets. I have fixed several such machines with odd symptoms just by replacing all the (dubious quality) original sockets with good turned-pin ones. This is normally the first thing I do to a PET. It may not cure the fault, but at least you then know there is a 'real' fault to trace.
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Thanks Tony, its definately worth a try!