Hi, I'm having a problem with my Sinbad 4 digit display...here's the problem: The 4 digit display does not display all the characters...some of the lines to not light up.

I thought the 4 digit display was broken but when I swap it to another machine it worked fine.  

So I figured it was a chip on the MPU board, so I brought another working MPU board to the non-working machine, but the problem is still there...

Therefore, the problem is NOT with the MPU board...any suggestions? Possibly the wiring harness?  Does anyone know which wires control which parts of the display?

Thanks,

Rich