RCA jack connection issue

sinnerboy

sinnerboy

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Hi, I have a Yamaha C-80 preamp that the pre-out left connection doesn't provide a sound connection. In other words, I have to wiggle the rca cable to get sound out of the left channel. I've cleaned the gold-plated connector, tried different cables but nothing seems to help. On the inside, it appears ok, but I'm not sure what to check. Probably a ground issue but I have no idea how to fix it short of replacing the rca assembly. Any ideas?
 
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Could be just a broken solder joint. Needing to be redone.

Pics would help but I think @avionic knows what it is and how to fix it and could describe that process if you can solder.
 
Here's a pic. Looks like a PITA to remove the rca inputs, they are attached to the pcb. If I knew what the issue was I will proceed, but I don't want to poke around without knowing what to look for. The workaround is to use the Inverse pair of jacks, which work fine
20200508_120248.jpg
 
Can be either cold/cracked solder joints on the pcb to RCA jack legs, that's easy to fix.

The less easy issue that can happen is if the outer/shell connection becomes loose on the contact points inside the jack panel. Far as I know that necessitates replacement.

FWIW, my C-80 had the cracked/cold solder joints and reflowing those fixed the intermittent pre out.
 
So the sleeve for the left channel input has a wiggle in it. Where the gold sleeve comes into the assembly (see pic). Is disassembly of the rca the solution? Appears that is your replacement scenario noted above. Crap.
20200508_120248~2.jpg
 
If the ground cap on the RCA jack is broken inside and you have a chunk of good metal from the outside to solder to, you can jump to the board from there. If you can not connect outside to inside, then replacement might be best.

On that board if there were broken solder joints they would be visible from below the board.
 
Agree with the above...

If the little tab sticking out is part of the problematic RCA jack outer contact, you may be able to solder a small jumper wire from that tab to the circuit return/ground.
 
It is broken internally. I see this frequently. Need to find a replacement RCA jack assembly.
 
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avionic said:
Inverted jacks.. Need to reverse the + and - on the speakers to be phase correct.
Click to expand...
Better solution..Provided you have a common ground amplifier.....Use the good RT normal Jack for RT channel and the inverted left channel jack for the LT channel..Hook the speaker wires to the right channel up as you would normally and on the left channel hook the speaker wires up + to - and - to +.... See the hook up diagram in the C-85 owners manual for using the inverted output with a single amplifier..:thumbsup:

C-80 is electronically identical to the C-85. C-85's manual is a better scan on HIFIengine.

Hooking up this way is a very very noticeable improvement. Especially for the low end sound reproduction.;)
 
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Thanks everyone. I'll follow @avionic advice until I can find a replacement jack, which appears to difficult even tho that style is widely used.
 
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