Hi Richard; if you can post some pictures of the inside on your control cavity it might be helpful.
So, it was working one moment, and then the next moment there was no signal coming from the bass?
You've checked all the usual things; fresh battery, different cable, different amp, etc?
There is no sound coming out when the pickup selector switch is in each of the four positions?
Are all of the pots tightened snugly to the body? None are loose?
Pull the guitar chord plug just a little from the jack so that it's not quite all the way in. Any change?
Inside the control cavity check that none of the circuit cards are touching the shielding paint.
Check that the battery connector does not have a short in it.
(Message edited by davehouck on December 20, 2010)