Ed - when you say it seems to be working normally, how normal it that? What I mean is, you will get sound if you jumper something that hooks just two traces out of the four back into action, but that's not what you want. The entire ribbon should read at least 4 and a half ohms. Try measuring the part you got to play and see what the resistance is.
Actually, whatever the problem, you are going to have to remove the ribbon from the cabinet and take out the little circuit board. That can be done without disassembling the ribbon, something you definitely do not want to do.
Cut the two wires first; they can be spliced later, with a bit of heat shrink and solder. All the outer screws in the metal flange have to come out. There are 10 - five a side - on a 48" ribbon, so I suppose 12 on your 60" - usually square-tip. Those magnets are powerful and will try to swallow anything they can, like your tool tip, or loose screws. So use care - easy to make things worse. The other bolts, the ones that hold the ribbon together, should not be touched.
The ribbon is heavy, and should not be jolted around - if you knock a magnet loose it's all over, and there are 60 of them in there! If you stand it up on end, make sure the top end is down, not the end with the wires - the little board sticks out there. (BTW, the rear felt cover is not removed for any repair, not even a full rebuild.)
Get it horizontal, and with the right little open-end wrench and a small Phillips you can remove the locknuts and bolts that hold the little circuit board, remaining wires still attached. What you see then is that there are four contacts that match up to the ends of the four aluminum traces. There is another little board at the top end, with a different bit of circuity, that reverses the direction of the traces. So electrically it's all one trace, but folded just so into a magnetic field -in - up-down-back up-back down, and return. Any break in continuity and that ribbon makes no sound at all, crossover or not.
Anyway, you have to find the break, or breaks - it could be the board got fried somewhere, but more likely one or more traces are broken straight across, right above where the edge of the board meets the ribbon. And it could be broken and still read continuity when you happen to measure. A lot of light and a good magnifier can help here. An ohmmeter (the kind that beeps for continuity is handy) with very dull probes used with a very gentle touch can be applied right to the trace and used to isolate the open point (or points).
One you locate this sort of break there are a couple of tricks for dealing with it. You could get lucky. After all, you had a couple of Rabbits feet there lately...
Let us know what you find.
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