This machine is an Assy No. 250425 Rev. B long board.
The machine would boot normally, but Control Port 2 showed faults using my 64 Doctor Cartridge. Nothing happened when pushing fire, right or left with a joystick.
The control ports are closely connected to the CIA chip at U1 (MOS 6526). I therefore started checking the physical connections (traces) from the control port to the chip as I’d previously ‘cured’ a faulty Control Port by exchaning this chip (link). All connections checked out OK.
I therefore replaced the CIA chip with a working one.
And now both Control Ports are working again and the machine is ready to do some gaming!
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