Correct wiring of the amplifier board for the JVC RC-838L

[Funkateer38]

Hello community, I need your help to have a photo of the correct wiring of the amplifier board for the JVC RC-838L. My unit shows many wires, pirate bridges.
Thanks for your help.

 

[hopey]

I think that maybe factory they did lots of mods on the process line. What's the problem?

 

[Arbusto67]

I agree with Hopey, I have a Nordmende RK4186, it's basically the same device and it's full of wires that go everywhere...

 

[Superduper]

RC-838JW.

 

[Funkateer38]

My problems to solve are numerous:
Amplification does not work
The MODE SWITCH switch is out of order, the 4 positions are not present. Mine is tinkered with shunts. I will replace it with another from a JVC RC-M70
The 3 BIPHONIC LEDs are off
The VOLUME and BALANCE potentiometers do not work.

 

[Funkateer38]

New, I replaced the 4-position switch, the biphonic is back with its front LEDs.
Repair of the BALANCE function potentiometer because a brush has come off.
The next step is to replace the pre-amplification transistor X103 ...

 

[hopey]

New, I replaced the 4-position switch, the biphonic is back with its front LEDs.
Repair of the BALANCE function potentiometer because a brush has come off.
The next step is to replace the pre-amplification transistor X103 ...

View attachment 57072View attachment 57073

Nice work. Funny how the mechanical contacts can fail but makes perfect sense. Contact cleaner is not a fix.