Les Paul Recording Transformer/inductor broken

[LardNotButter]

Hello all, 

I've got a 1972 Les Paul Recording that my uncle had bought secondhand from a friend in the late 70's, and he had given it to me before he had passed last year. I've been into general guitar electronics wiring for some time now, so I was interested in what was under the hood of this oddball model. Once I looked over it, I noticed the little yellow box with 4 colored wires coming out of it was damaged, and the wires were cut incredibly short. My multimeter didn't read a thing for any sort of resistance/impedance/capacitance, so my first intuition was to buy a new one. Only issue was that I couldn't find out exactly what value it was, what sort of part it was, or where to find one. Does anyone know what that little yellow box is, and where to find one?

 

Thank you very much in advance!

[Grog]

Raw Shure mic transformers are available on eBay. Many Shure inline transformers work when the guitar is set to low impedance. Aftermarket Shure replacements should work also. It was common in a Les Paul Professional to find an inline transformer soldered in the control cavity so the users didn’t have to use a transformer chord.

[LardNotButter]

Is there a set value I should look for? or were they all just the same?

 

P.S, The decadance switch has been replaced with a varitone switch similar to an es 345, and I don't know where to find the original decadence switch anywhere, is there a serial number I can look for?

Edited October 10, 2023 by LardNotButter

[Grog]

I have several Gibson Replacement Parts books. They use Gibson part numbers which you might not be able to reference to an equivalent part today, but it might help. The last section of the second page is for the 1971 to 1977 LPR’s……..

[Grog]

This is what I bought on eBay to have replacements for the transformer.

 

 4PCS Replacement Transformer Fit For SM57 SM-58 Microphone | eBay

 

Note* The Decade switch is actually 11 position even though its name suggests 10 position……….

 

Edited October 10, 2023 by Grog

[LardNotButter]

I found a similar switch, but I'm not sure if it's the right one, but looks very promising. 

 

https://www.ebay.co.uk/itm/333782161398

 

And for the transformer, do the 2 leads on each side matter where I solder them to? Or does the color code matter at all?

[Grog]

Looks like Red & Black are high impedance with Black being ground. Yellow & Green are low impedance, not sure if these matter how they are wired…..

Switch does look promising!

Edited October 12, 2023 by Grog

[LardNotButter]

So with that said, Should the green and yellow wires go to the pins where the red and orange are in this photo, and the black and red wires go to the pin where black and yellow are? and since the orange wire isn't being used in you diagram, could I snip it short and tape it off?

Sorry for bombarding you with so many questions but I want to know one more thing. Is the switch the one I found the one in the LPR? 

Edited October 12, 2023 by LardNotButter

[Grog]

I think the Red & Orange wires are high impedance, Same as Red & Black on the replacement transformer. The entire circuit is low impedance, the switch just adds the transformer into the circuit so it can be plugged into a (normal) high impedance amp. Here is a simple one I did a few years ago, a lot les wires.

The switch looks about as close as you are going to find fifty years after the fact. The shaft on the original has splines, you will have to use a knob with a set screw. It is made by CTS like the original.

Edited October 12, 2023 by Grog