This one's a little tricky since it has a Print Timing Sensor (PTS) which is a slotted disk light sensor that will send pulses to INT1 of the upd7810.
It would move the carriage a little bit then start beeping until I made it send some pulses to the INT1 depending on carriage movement.
That works a little bit, but the self test will stop after 3 lines. I think it's erroring out because the pulses don't match the timing expected:
More experiments to see if that fixes it.