JT>After a bit of fiddling (sometimes a slight mechanical agitation)
JT>it starts working again.                    ^^^^^^^^^^^^^^^^^^^^
You mean you whacked it?
JT>I took it apart and looked for 'obvious' stuff, even re-soldered
JT>all the ground leads and jumpers to make sure it wasn't a cold
JT>solder joint.
How about less than obvious?
I had a similarly weird problem with a TV remote. Whacking sometimes
helped, and just holding it differently would sometimes make it work.
I used my trusty VOM to follow the circuit traces from each battery
terminal as far as possible along the board, checking at each exposed
connection along the way for loss of continuity, as well as each minor
trace between components.
I found:
 - One broken trace. Needed a magnifying glass to see the crack.
 - A few end-of-trace solder pads that had broken loose from their
   traces. The components were still firmly attached, so the remaining
   good pads prevented the parts from wiggling, and kept them close
   enough to make occasional contact.
A jumper wire over the break, and extending the pads' solder onto the
traces, and now everything is wonderful.
 * SLMR 2.1a * 
--- Maximus 3.01
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