This is an error I've never gotten before, been running this machine for 15 years or so. Searching here revealed a reply from sportybob on this error, saying to check the 5v supply and bump it up to 5.2V to avoid communication problems. I checked the 5v supply in the back box with a meter and it was running at 5.0V, so I bumped it up to 5.2V and doublechecked that this voltage was making it to the board by clipping the meter onto the wires that run directly to the board and verified that the board was receiving 5.2V - however on restart got the error again.

Anyone have any info on how to troubleshoot this further if the voltage looks ok? I also verified that the wires running the 5V to the board had good solid connections at the board. Any help greatly appreciated - sportybob do you still make it by this forum? I seem to recall you having encyclopedic knowledge of all things Milltronics...