450-12 1965 electronics

[Liam]

I have a 450-12 from 65 and the bridge pickup is weak when compared to the neck even after adjusting for height.
I asked the schematic is not available from Rickenbacker.
The wiring appears original. Anyone have a diagram? Its the one with a three way switch and 4 pots with the extra.0047 tone cap.
thanks!

[maxwell]

viewtopic.php?t=418233

…hmmm, this seems familiar.

That .0047 mfd cap is the problem. Read through the linked thread.

[doctorwho]

I have this bass schematic (from the Rittor book, the one on the right) readily available:

Rittor-Wiring_cr.jpg (191.29 KiB) Viewed 4424 times

Being that it shows a four-control-mono-out circuit, it's likely similar to the one in your four-control 420.

I'll check my other files/books to see if I can find one specific to the 420.

[Liam]

Thanks a lot one on the right looks good for this guitar-
Im not an electronics person by a long shot.
Taking readings from the cable when the bridge pickup is engaged
I get a reading of 100k. Neck pickup or boht it seems normal/
but I desoldered checked the cap and there is no resistence.
Its a mystery to me. In the bridge position the pickup works as does thevolume and tone
but the output reads 100k- that doesnt seem right, Or is it?
I dont want to take it apart as it has not been touched other than when I checked that small cap.
Guess Ill have to take it to someonewho knows. I think it must be a bad pot.

thanks again for the drawing.
cheers Bill

[Liam]

Okay Ive researched and found this " Pickup impedance can be most readily be measured from the output jack on most guitars (all controls fully extended). Notable Rickenbacker exceptions are: 1) three pickup models where the neck and middle pickups are tied, and 2) older models with a series capacitor in the bridge position."

in a 25 year old post. My 12 string guitar has the series cap in the bridge position.
Question: Does anyone know if that fact ^^^ along with the interactivity of the 4 pots with each other, could account for the reading with the switch on the bridge position at the guitar cable of 100k?
Sure seems to be an odd arrangement.

[doctorwho]

I have a copy of the two-pickup, four-control, mono-output circuit that was available at the old Rickenbacker website:

GB4C2PM.gif (9.45 KiB) Viewed 4402 times

FWIW, I think the "4000" under Application is a typo (should be "4001").

While looking for this, it dawned on me that my 1999 450v63 JG has the same pickups/controls configuration:

450v63JG1999.JPG (157.33 KiB) Viewed 4402 times

I had taken some pictures of the body under the pickguard, but they don't show all of the controls/pickups (I wasn't concentrating on them at the time).

oh, BTW ... I plugged a cable in and measured the resistance ... I was getting 102 kOhm, similar to what you got.

[Liam]

Thank-you!
That settles things perfectly.
I appreciate all the info .