Rick wiring help

[Brian Hart]

I have a fairly new Rickenbacker 330 on my bench.  The neck pickup has nearly no output, but measures the same as the bridge when disconnected and tested against the bridge pickup.  With what little bit I can hear, it's tone pot is also acting as a volume pot.  I checked everything against a diagram and everything looks to be in place.  I'm hoping somebody has an (oh I fixed that, here's what's going on) response for me.  Any guidance is much appreciated.  Thanks!

[Paul Verticchio]

Have you checked the function of the "Mix" control?

Here's the schematic. http://www.rickenbacker.com/pdfs/19511.pdf

Any further answers will require a photo (or several) of the subject guitar's current wiring scheme.

[Robbie Collins]

Perhaps a pot got too hot when soldering it and is shunting signal to ground.

[Joshua Levin-Epstein]

A fried cap will make a tone control act like a volume control.

[Len Biglin]

Yes it sounds like a shorted tone cap , is the magnet in place on the neck p/up ? try disconnecting the tone cap and see if the volume restores , or measure the K Ohms at the end of your lead , is it about the same with either p/up selection , and with tone turned down ?

[Paul Verticchio]

I'll agree with a defective cap, but a fried cap in a circuit that sees nothing but millivolts would be surprising.

I think we're due an update from Brian to see what he's discovered so far. :)

Brian: I forgot to suggest re-flowing ALL solder connections as part of the diagnostics.

[Brian Hart]

Thanks guys.  I'm taking care of some other jobs today, i'll be on it again soon.

[Joshua Levin-Epstein]

The frying I refer to is usually the result of a soldering iron.

[Russell Vance]

Hi Brian,

In the absence of a skilled electronics background I suggest you stop having shots in the dark and adopt a systematic approach:

Firstly, wash out all the pots with Caig or S-26 while rotating the pot shafts full range back and forward. Similar with switches - back and forward  

Blow dry with compressed air (not too high a pressure), repeat the wash out.  To do switch contacts use a piece of textured paper soaked in Caig to slide between the contact points.  Abrasive paper will cause failure down track due to the contact plating/protection being removed - so don't use it. Test.

Go through with a pair of tweezers and pull all the wires to check they are firmly connected at the solder joint.   Test.

Disconnect both pickups and hot wire them to a separate output jack and test each with the amp. Wiggle the connection wires to check for intermittent connections.

Resolder the pups (which also discounts dry joints at that place) and remove the tone pot and cap lead.  Check output.

Change over the leads on the selector switch to see if the problem goes with the change - ie swaps from neck to bridge.  If it does replace the selector switch and test.

Change over the two volume pots to see if the problem swaps sides, ie moves from neck to bridge.  If it does the problem is likely in the volume pot.  Hook up a multimeter to the bare pot and rotate the shaft while wiggling and stressing it at both ends to check for wiper contact and over-run at the ends of the resistive strip)  Replace if the multimeter flickers (you need good hookups with your probes).  Test.

That's a quick and dirty to get you started.  For simple wiring this stuff can still make you tear your hair out.  

There are guys on the forum who can do it quicker and better but in their absence it's a safe but tedious solution thus far.

Rusty.

[Brian Hart]

Here's my most recent stab at it.  Replaced volume and tone pots.  Disconnected capacitor for the time being.  The pickup still is weaker than the neck even though it reads hotter than the bridge on the meter.  Tried a fresh capacitor, and the tone pot still acts as a volume control.  Checked the underside of the pickup, and everything is connected as well as the magnet is in place.  I guess the switch is next, but I feel like i'm missing something.  I'm not shy to say that wiring doesn't come naturally to me in a guitar that is a little bit ass backwards from a normal 2 pickup setup.  

Then all of a sudden, everything is normal.   I tug on the wires to make sure it stays that way, put the guard back on, proceed to make a comment my associate and then out of nowhere, it goes back to low output, tone as volume, all over again.  I stripped back all of the double lines (hot and ground in one wire) so make sure they weren't touching farther back, wiggled everything, checked over and over, and still nothing.  

[Joshua Levin-Epstein]

Have you, as Rusty suggested, tied the pick-ups (one at a time) directly to a jack and to an amp? The tone control will act like a volume with a (damaged coils) bad pick-up.

[Brian Hart]

Yup, took a reading and also gator clipped the neck pickup to it's own jack and strummed a few times, then swapped the cable back to the guitar's jack and compared the bridge volume and it was comparable.  

[Paul Verticchio]

Brian,

At this point, I can only suggest rewiring the whole thing with new wire.  It's been my experience that rewiring can eliminate hours of frustrating "diagnosis", as you've experienced. I do this as a first choice if the sort or open is not visible in the circuit.

A question I should have asked MUCH earlier: You mentioned the instrument is "fairly new". If so, and the owner is the original owner AND this developed before the circuit was diagnosed, he should have been advised to make a warranty claim with Ric. My personal advice to customers is "If it's still under warranty, make a warranty claim".  "Warranty costs" are part of the high prices they charge for those instruments. But in this case, the warranty was voided the moment you removed the assembly.

And again, have you checked the MIX control. According to the schematic, it has a tremendous influence on the neck pickup.

Josh: thanks for the clarification. A major "duh" moment for me :)

Good luck with chasing this dragon.