Active Pickup

[Jazz P Bass]

Just got in a Peavey Millenium 5AC bass guitar.
The bridge pickup does not work.
I ordered a new one from Peavey, it just leaves me curious as to what is inside the pickup.
What's up with the 18 volt wire going into the pickup?
Are there active components inside with the coil or are they using the voltage for something else?
It is a sealed unit so I cannot tell what is inside, nondestructively.

[Marko Ursin]

There's a preamp inside the pickup cover. That's why 18V goes in the pickup.

[David King]

Maybe it just lights up a little bulb inside the pickup, that wakes up the ant colony, that chews up the cellulose in the bobbin, that causes a little burst of methane, that builds up pressure and jets out the end of the wire causing the control cavity to fog up. That in turn helps the electrons move through the volume pot carbon wafer causing the guitar to play louder and smell vaguely of rotten eggs? Seems like it should work.

A dead pickup would make an excellent candidate for destructive post-mortem examination. Even if just to let the ants out.

[Jazz P Bass]

Ahh, but how to remove the epoxy encasing the pickup.
I am putting in a call to Peavey on Monday.
Will post the updated info.
Curious I am.
Edit: I removed the pickup & it started working.
Banged on it, shook it, checked for intermittant wires.
And still it worked.
Put it back in, played it for an hour.
Next day (the guitar did not move) nothing from the pickup.
A new one is on the way.

[rjb]

Ahh, but how to remove the epoxy encasing the pickup.

Heat gun and pokey-scrapey things. I used a screwdriver-shaped plastic probe to strip a Peavey T-60 pickup.

[David King]

I suspect that the hot wire is shorting out against the shield at the sharp, right angle bend under the pickup. I've seen that happen before, raise the pickup a bit and the short goes away.

[Jazz P Bass]

Yeah, I thought as much.
There are three parallel pieces of foam stuck to the underside of the PU. (poor man's springs)
As I said, I did the wiggle test of the wires while it was functioning & it kept working.
I cannot in good faith rip into this thing until I have the new one in hand.
Which reminds me, I have to give Peavey a call.

[rjb]

I suspect that the hot wire is shorting out against the shield at the sharp, right angle bend under the pickup. I've seen that happen before, raise the pickup a bit and the short goes away.

Does that mean it can be fixed with a piece of tape or heatshrink? I've never seen one, so don't know.

[David King]

I don't think there's an easy, sure fix unless you can replace the bad cable or remove the inner conductors from the braided shield. It's the insulation on the inner conductors that's breaking down.