Make sure the input jack has 3 leads, not just 2. 1=signal hot (tip of plug), the 2nd=ground connection (shaft of plug), the third = - lead of battery. When the cord is plugged in, the 2nd and 3rd lead are connected, powering the internal preamp.
Verify when the cord is unplugged, the power is disconnected, check for voltage at the circuit board.
My guess is you hooked the - of the battery to the ground connection (ring, shaft of plug), so its on all the time, and the signal ground is what's getting switched on when you plug in the bass instead of the - of the batttery.
|
1 signal hot ------v | plug
| <====
3 batt - -----------------v---^ |
2 circuit ground --------------------------------|
When bass unplugged, there's space between 2 and 3, they're not connected. No power goes to preamp circuit. When plugged in, tip of connector touches 1, shaft of connector touches 3, and moves it over to contact 2, which completes the power connection. Or the shaft of the plug makes the connection, instead of bending 3 into 2. I've seen both. But if you hook battery - to terminal 2, its always connected to preamp circuit.
Randy
Ok, drawing looks like crap when posted..... I'll try it horizontal...
Plug:
II
II
V
_____________ <=2 circuit ground (ring of jack, signal gnd)
|
|
| >
| |
| <
| |
| |
| |
| |
| |
| | >
| | |
| | | <= 1 tip of plug
| | |
| | |
| |
| |<-- 3 (-) of battery
|
| <= 2, signal ground (ring of jack)
