About a million of them, Halcro :).
Here are some quotes from my tech to perhaps narrow things down.
The PCB is two sided but without plated through holes. It looks like they put eyelets in and then solder on both sides. I found one that was open but by the time I pulled the PCB it was connecting. I resoldered it and now the 45 light comes on and that speed works. The 33 light never comes on so I think there is something wrong with that flip flop....
Doing just the few that looked suspect did not work (it did work but only for a day and then the gremlins reappeared), so after trying several other types of fixes, he ended up doing them all:
There were no bad parts, just bad connections. I ended up resoldering all the feed thru eyelets, then flipping the board and removing the solder with a sucker, then resoldering them with much less solder. They all look pretty clean now. I know other companies that used the eyelet method had reliability problems. For some reason the solder cracks around the eyelets, probably related to different coefficients of thermal expansion.
So, look for the joints that utilize 'eyelets' (I'm not sure whether that's a subset of all the joints or all of them). I think it took him a couple of hours to do them all, so not too bad.
