Cartridge wiring continuity/troubleshooting

[likebike23]

If that were the only problem, it would only affect 1 channel, and that channel might actually work.

The relay contacts are NOT in series with the signal path. They merely short the signal to ground to achieve muting.

ie, if you remove the relay from the board, the signal path remains intact, and muting is non-functional.

But that's why I suggested blocking the relay contacts from closing, it's easier than removing the relay, just to determine if the relay is at fault.

I can see that the joint I highlighted was for the right channel, it was simply the worst looking of what appears to be a few bad joints. Anyway, I would be thinking of eliminating the relay board from the equation too. I considered suggesting that the OP desolder the tonearm wires and connect them directly to the RCAs just to test it.

 

[HalfApt]

Without knowing what a previous owner has done inside, it's hard to say what the best troubleshooting procedure would be.

The relay does not interrupt the signal path, it merely shunts it to ground. He has already confirmed continuity from cart socket to the end of the RCA plugs, so it would seem the 4-pairs of board solder joints are intact.

Eliminating the board entirely would be a lot more unsolder/re-solder work than simply blocking (or removing) the relay.

 

[HalfApt]

I tried disconnecting the 4 pin white connector that goes to the relay. I can see that there must be a preamp built into the other board, as that 4 pin connector goes from the mute relay to the other board, and back from the other board to the 3.5mm line output. I thought maybe something was wrong there, so I disconnected that connector, but it didn't make a difference.

That won't have any effect. 2 of those wires are power to the relay, without them the relay will never operate, and you'll always be stuck in "mute". The other 2 wires are "sync" signal.

Beware! The 3.5mm jack is NOT a line signal. It is a "sync" signal to start/stop recording on a compatible tape deck. Don't plug it into any preamp input.

I am a complete Noob when it comes to AC circuits. Is it possible that capacitor could have gone bad and is causing this issue? How does one test a capacitor with a multimeter?

Anything is possible. If it's shorted, the relay won't operate. If it's open or out-of-value, the relay should still operate. What value is that cap?