Denon UD-M31 CD Receiver clicks on and off

[ryanjaredmartin]

I own a vintage Denon UD-M31 CD Receiver Compact System with the mission speakers. It sounds great.

From time to time, the unit will (randomly?) click off. Sometimes this happens when I switch inputs (labelled function on the remote). When it clicks off under these circumstances, there will be no "clicking" sound that I often hear while switching inputs. Sometimes the unit clicks off while I have audio playing. Sometimes it clicks off in the morning. Sometimes in the afternoon.

It has always fixed itself. Sometimes I turn the unit off and wait a few minutes. At other times, I simply let the unit continue as is, and it will click off. At other times, I'll switch it over to the tuner to make sure the problem isn't with the input, and the audio will click on. At other times, I'll switch over to the tuner and have to wait several minutes before the problem is solved.

I've tried moving the unit out of the sunlight. I've tried dusting it (though not removing the cover). I've tried making sure it has proper ventilation on all the sides of the unit. The unit does not seem to be inordinately hot. I've also checked all the speaker wire connections. There doesn't appear to be any issues (loose wires, etc) at the connecting points behind the speakers (I'm using banana plugs) or behind the unit.

You can see pictures of the unit here, though that probably won't help. https/photos.app.goo.gl/z1qcTso4HLsuUB8G6

Anyone have any idea what might be causing this or what I might be able to do to fix it?

 

[americanaudiophile]

Sounds like a bad relay in the Denon. If you want to mess with it the service manual may help
http/service-diagrams.com/service_manual/Denon_UD-M31.pdf
FYI though its a nice mini system and does sound decent it's not old enough to be vintage.

 

[ryanjaredmartin]

Thanks for the response. I'll see if I can figure things out.

I appreciate the clarification on the descriptor "vintage."

 

[DaveEvenden]

On the 2 or 3 occasions (since 2003) that I have had very similar symptoms, I have found that re-seating the stacked PCB assembly works nicely. My pet theory is that over time these connections loosen (or something). Anyhooo pushing down on the back of the PCB with the audio input connectors (the back faces upwards) seems to do the trick and gives me another few years of life.

This does require taking the case lid off (side and rear screws), but does not need anything technically advanced. The usual cautions apply for mains powered equipment.

Hopefully this response isn't too tardy.