Sorry to see you never received a response to this. I don't have anything to offer but find myself in a similar situation with a Bride of Pinbot. Did you find a solution? Thanks...

How about a pic of your problem.

Will see if I can get a photo, but similar issue as shown in the second photo above. To describe it: in the top display, first letters of words or first digits of large numbers display weakly while other letters or numbers display fine. Problem is not dependent on position in display--always first character is bad independent of position. For example, in the photo above, the i of insert coin is weak; on my display the I and C would be weak.

Given some reading of posts of display issues and inquiries with folk who have discussed similar problems I am lead to believe that the display is going out and so am looking into purchasing a new led unit or finding a substitute for the current display.

As you can see, the g and o in 'game over' and the r and a in 'replay at' are weaker than other letters. Again the problem is that the first character in a string of letters or numbers is always weaker than the others in the top display (bottom looks great!).

IMG_0195 (resized).JPG

IMG_0197 (resized).JPG

This most likely is a display on its way out. But start with basics and check your voltages for the display.

When you look at you first pic its more than the first digit, also the third and fifth.
You may want to try a new ribbon cable.

How are the voltages at the display board?
Do you have the correct voltages?
+100V at R82 and -100V at R53 present?
I'm not sure about the resitor numbers, but the are the 330K ohm resistors.
These are orange-orange-yellow-gold.
One end is ground and the other end is the voltage.

Thanks for the advice and details! Will check ribbon cable and voltage when I get the chance.