[PETERg0rsq]

I have made progress, and the signal generator now boots up every time.

Problem was with a high resistance track to the ROM1 CE pin.

However there is a new problem, which I am presuming I have caused.

At the end of booting the IRQ is constantly pulsing, and it seems to be from the PIA. As soon as I touch a button the 6802 locks up.

I checked the DATA BUS for any floating logic, but found the waveform on all the DATA pins to be very poor (see picture).

I removed all other chips on the DATA line, so now the only components connected are the pull up resistors and the 6802, and the waveform is just as bad. I have replaced the 6802, and it is identical.

What can cause the problems, or is this normal?

The ADDRESS pins show a good square wave form on rising and falling edge.