Epiphone Jack Cassidy wiring

[Waxwing]

I have the JC bass that has a couple of issues. 1 - output seems low, 2 - no perceivable change when switching the varitone. I have a schematic but this bass is not wired at all like the schematic. According to other threads, it's not uncommon for this bass wiring and the schematic to be quite different.

My electronics troubleshooting skills are not the best so I'm hoping someone out there knows something about the wiring. If I posted a photo of my wiring, can someone check it over and see if there is any reason for the above two problems?

I would really appreciate any assistance!

 

[SGD Lutherie]

It should look like this:

 

[Waxwing]

Thanks! Your wiring diagram looks a lot like the schematic but I'm no expert. At least the pot wiring looks the same, but I get lost at the switch and transformer. My bass does not have any caps or resistors wired to the pots and my pots are 25k, not 2.5k as indicated on the schematic. Have you actually wired up a bass following this wiring diagram and it worked? Should I stick with my 25k pots or try to find 2.5k pots? Thanks, really appreciate your help. I'd be lost without it!

 

[SGD Lutherie]

Did someone rewire that bass?

 

[Waxwing]

Yes, I think someone has done some work on it before I got it.

 

[SGD Lutherie]

OK, I'm suspecting that the pickup are not going to the transformer, and that's why the output is low, and the impedance selector switch (varitone) doesn't work. They are low impedance pickups, so you either need the transformer or a preamp to get the levels up.

Is the transformer still in the bass? You need to get it wired up like the schematic.

 

[Waxwing]

Yes, the transformer is there, just not wired like the schematic. It's totally different. What do you think about the pots? Should I use the 25k or try to find 2.5k? Lowering the resistance value of the pots will make the tone a bit more warmer ... is that right?

 

[Waxwing]

Talked to Gibson tech support. Here's the schematic they sent to me.

 

[Stealth]

I'd say Gibson messed up the values - those should definitely be 25Ks, not 2.5Ks.

David, is that from the big bad book of wiring by Cadfael? Amazing PDF, that.

 

[SGD Lutherie]

I'd say Gibson messed up the values - those should definitely be 25Ks, not 2.5Ks.

No, it's 2.5k. The pickup only reads 23.3 ohms!

David, is that from the big bad book of wiring by Cadfael? Amazing PDF, that.

Yes it is. Now I have to learn German ... (You would think I would know some with my last name!)

 

[southpaw219]

A Jack Casady bass came across my bench today. The varitone knob had come loose and, apparently, the owner kept trying to turn it and sheared all the connections from the switch.

One thing that's interesting to me is that the transformer seems to be filled (or at least covered) by enamel. So is the back of the pickup. Any idea why this is?