03-18-2026, 02:06 PM
I picked up a 39-116 (technically 39-3116 Canadian version) a few months ago and have completed recapping and installing a bluetooth transmitter.
This is my first old radio and my knowledge of the inner workings are minimal at best so I've been flying blind for the most part and trying to navigate the schematics available.
I have two issues.
First, as I went through everything I realized that the radio has been fairly significantly worked over at some point with entire circuits added and added/changed wiring. I've been able to trace most things down but there is one beige wire that goes out the front of the cabinet that has been poorly spliced at some point and is no longer connected to anything.
Inside the cabinet it is connected to a terminal of a wave switch near the oscillator transformer. I've circled it in red in the attached picture. The wire runs out the front of the cabinet and terminates near the wiring for the preset bulbs. I haven't been able to locate any obvious spots where it may have broken off. Notably, the wire is rubber coated and the majority of the other wiring is cloth under the cabinet. Rubber coated wiring is used for the light bulb wiring elsewhere.
The second issue is with regard to the volume potentiometer. When I initially powered the unit on, I was not getting any sound except for in one position on the pot. I suspect this is where it sat for many years. I've taken the potentiometer apart and cleaned it multiple times with de-oxit, I now have good sound in that one position (about half volume) but scratchy/distorted sound if I try to go any louder. I suspect I'll have to try replacing it.
The related issue I'm having is with the bluetooth input. It has its own power supply and the output is wired directly to the volume potentiometer (stereo output to 10k resistors that are tied together and then wired to the pot). If I try to increase the volume above about half way on my phone or the bluetooth module, as soon as there is too much audio input the sound will cut out/clip. I haven't seen this issue mentioned elsewhere with bluetooth adapters. I suspect the input is overpowering the position of the pot somehow, or maybe is just related to the already iffy potentiometer, but would appreciate input from more knowledgable people than myself.
Thanks,
Jeff
This is my first old radio and my knowledge of the inner workings are minimal at best so I've been flying blind for the most part and trying to navigate the schematics available.
I have two issues.
First, as I went through everything I realized that the radio has been fairly significantly worked over at some point with entire circuits added and added/changed wiring. I've been able to trace most things down but there is one beige wire that goes out the front of the cabinet that has been poorly spliced at some point and is no longer connected to anything.
Inside the cabinet it is connected to a terminal of a wave switch near the oscillator transformer. I've circled it in red in the attached picture. The wire runs out the front of the cabinet and terminates near the wiring for the preset bulbs. I haven't been able to locate any obvious spots where it may have broken off. Notably, the wire is rubber coated and the majority of the other wiring is cloth under the cabinet. Rubber coated wiring is used for the light bulb wiring elsewhere.
The second issue is with regard to the volume potentiometer. When I initially powered the unit on, I was not getting any sound except for in one position on the pot. I suspect this is where it sat for many years. I've taken the potentiometer apart and cleaned it multiple times with de-oxit, I now have good sound in that one position (about half volume) but scratchy/distorted sound if I try to go any louder. I suspect I'll have to try replacing it.
The related issue I'm having is with the bluetooth input. It has its own power supply and the output is wired directly to the volume potentiometer (stereo output to 10k resistors that are tied together and then wired to the pot). If I try to increase the volume above about half way on my phone or the bluetooth module, as soon as there is too much audio input the sound will cut out/clip. I haven't seen this issue mentioned elsewhere with bluetooth adapters. I suspect the input is overpowering the position of the pot somehow, or maybe is just related to the already iffy potentiometer, but would appreciate input from more knowledgable people than myself.
Thanks,
Jeff




