Problem with Gibson Thunderbird pickup (electrical help appreciated)

[Cyber_Chyld]

Hey guys. I'm trying to troubleshoot a band mate's Gibson Thunderbird Studio V bass.

 

For some reason the output level seems to have dropped and become 'thinner', it's also buzzing like crazy all of sudden

 

I had a quick look to see if anything has become unsoldered (screens etc) and it all looks fine. I can only wonder now if a pickup has perhaps failed:confused:

 

Does anyone know what reading I should be getting from a multi-meter from an A-OK pickup?

 

All I can think is that perhaps one of the pickups has gone faulty in some way and is loading up the other pickup. It's a mystery!

[Ancient Mariner]

I sounds like an earth has come off somewhere - check the jack. If it were a 1 pickup model then I'd suggest the PU may have gone open circuit, but that buzz much more suggests a faulty earth connection.

[Cyber_Chyld]

I sounds like an earth has come off somewhere - check the jack. If it were a 1 pickup model then I'd suggest the PU may have gone open circuit, but that buzz much more suggests a faulty earth connection.

That was my immediate thought, it has the makings of a bad earth.
I did have a quick glance in the control cavity, and all the screens appeared intact.

I think my first plan is to unsolder the pickup leads and check the pickups with a meter. Someone on the bass forum has suggested they should be reading about 10K.

Once I know the pickups are working fine I can start working through the rest of the circuit.

[Ancient Mariner]

You could just stick the multimeter on the output jack first, before unsoldering anything.

[Cyber_Chyld]

You could just stick the multimeter on the output jack first, before unsoldering anything.

Yes, I suppose you're right, it's twin volume master tone arrangement. I guess I'd expect to see double the reading for both pickups? I don't know if they'll be wired in series of parallel though