I have a Williams F15 that had batteries that leaked many years ago. I just had the motherboard repaired by a company out of the Chicago area, the workmanship looks great and almost everything seems to be working fine... that is except for Display 4

All of the displays used to work before I had the board repaired
Looking at the condition of the display board I would lean toward the problem being with the display board but not really sure.

I did reach out to the company who rebuilt the board but the more I look at this I fear that display 4 died and I don't think that this is the first time this has happened. Of the 4 displays, none of the displays look like they are from the same manufacturer

Both display 1 and 2 are slightly different and have sloppily applied 2 sided tape on the display supports
Display 3 still has a black surround and the digits and display 4 is missing the display supports completely.

Funny thing is, since Display 3 still has the black surround I would have thought that one would have been original but honestly the solder joints kind of suck on that one, then again, none of the solder joints don't look that professional.

To add to the mystery, there are two black wires soldered on the back of the board connecting Display 4 to Chip U14.

I am looking for some suggestions

Is there an easy way to test Display 4?

The other three displays work fine and pass the system display test but I have no idea if, short of a used display, I could get a new display that would look similar to the rest and replacing all 4 displays is well out of my comfort zone.

If it matters, the Board Number is
5760-12134-00 Rev. - SAM D
D-11610

Thanks for any assistance you may be able to give.

Bob

Sorry, I wasn't thinking. Yes, the wire is likely a trace repair but I added a photo anyway.
I also included a photo of the display thought I don't know if it is possible to diagnosis this from a photo

None of the other displays look great but they work just fine.
According to a schematic I found online, there are two power connections on the display

Pin 6 100 volt + and Pin 7 100 volt - I have 65.4 volts here
Pin 34 100 volt + and Pin 31 100 volt - I have 65.4 volts here

I checked the working display next to it and the comparable terminals were within .1 volt at 65.5 volts.

Given my vast knowledge if electronic theory, I mean, I stayed at a Holiday Inn Express last week...
It sure sounds like display 4 has gone the way of the dodo.

Am I on the right track and I should start looking for a replacement board?
I have seen several that use modern components on line.

Is there a better suggestion out there?

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Just wanted to follow up...

After much soul searching and several visits to my therapist I decided to buy a new board from Dave at Wolffpac Technologies. It was a DIY kit and I probably could have assembled it but for what he charged for assembly it wasn't worth taking a chance. It works great and the machine is back to working after a really long time. Thanks to everyone who helped me.