[Dennis McGarry]

Hi, I am the new owner of a pristine BeoGram 5000, the trouble is that one channel has no sound. I am pretty sure it is the Muting Circuit.

I have done the test with the cartridge out and in “play” mode, taking a strand of copper wire and putting it into cart holes, –I only get a hum on two of the holes (I should get hum on all four if the TT is putting out 2 channels). I have verified continuity on the DIN/RCA adaptor. I have looked at the stylus under a microscope, it is in great shape. So I think those are fine.

Is there a way to bypass or clean/recondition the muting circuit switch? There are some old posts in the archives on this issue but all seem to be inconclusive, and don’t describe a fix.

I really want to bring this gem back to life–Thanks for any suggestions or advice!

[Glitch]

Dennis McGarry wrote:

Is there a way to bypass or clean/recondition the muting circuit switch?

One way to debug mute relay/switch problems is to simply remove (or disconnect) the mute relay/switch. The mute relay/switch grounds out the L and R signals from the cartridge. Without it in the circuit, the phono should still play music (if the problem isn’t something else). Removal also makes it easier to test continuity of the traces/wires between the cartridge and the connector on the back of the phono.

Replacement of the relay/switch is preferable to cleaning. If a replacement isn’t available, cleaning should be done with the least aggressive method that yields results. Of course, cleaning is easier with the part removed.

Glitch

[Dennis McGarry]

Thanks for that– and one update, I verified the cart is ok–the cartridge has 770 ohms measuring both ways-measuing pins horizontal and veritcal. measuring the din conntector–The Din connector–between pins 2 and 3, I get the 770 ohms, but between 2 and 5 I get nothing. I should add that the Din measurement was taken while a record was playing, with cartridge. thanks so much for your thoughts.

[Author]

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