trying to troubleshoot not working displays on a newly aquired game. only player 2 shows a few digits but its gibberish. player 1 and 3 had shown some gibberish as well, but now they are completely dark.

my question is if anyone has some instruction as to how to diagonose if display issue is MPU or display board related.

i have a c-10877 display board. i have checked the 6118a and U9, U12-14 chips for shorts, as well as replaced U41,42, and U44 on MPU all to no avail. also r1,r4 on power supply.
thanks.

Awesome thanks for the hint. I'll let you know.

Haven't checked 100v yet. It's on my to-do list lol. Could voltage issue cause the scrambled digits?

i found this, which may answer my question.
http://www.pinwiki.com/wiki/index.php?title=Williams_System_9_-_11#Logic_States_of_Display_Output_Signals_for_a_Working_MPU_Board
*edit(this actually wont work in my case, as i dont have a that type of display in High speed)

i was not able to switch my display with the Jokerz display. they are different generations, with cables that didnt match up.

something is dying as i power it on momentarily tho for sure. since i got it, and have turned it on just occasionally to test displays, its gone from players 1-3 working, to 1-3 scrambled, to only player 2 scrambled, and now all blank.