What's PB?
Pushbutton unit.
Is it worth swapping out the black box?
Of course. Unless, of course, it's too expensive for a gamble. It's the old song. You can use electrical test equipment to see if it's getting good inputs, then you can see if it's generating good outputs. Quite a bit more time-consuming than just swapping in a known good unit. However, coming up with a known good unit can be the hard part of doing it that way... -- Jim
