Vestax PMC50a, All channels intermittently dead.

[Ranga]

Hello all, I've recently dug my old DJ mixer out of the cupboard and it works fine - intermittently. When it works, it works fine, like absolutely great. When it's not working, the power light is on but all of the channels are dead, phono, aux and line. Microphone input dead. Everything dead. It's very strange. Bizarrely, a few small taps can sometimes make it work again. I know the channels work as when they work they work as they should. What could be causing this intermittent loss of power to the channels? Could it be a case of a loose wire somewhere given a tap sometimes knocks it back on? Or could it be something more serious?

Any ideas peeps?

Cheers

Ranga

 

[Harald Kapp]

A bad (dry) solder joint could easily be the cause for this. Look especially at the connectors where the signals enter and leave the PCB. As these are subject to mechanical stress, their solder joints sometimes come loose (and re-connect by tapping as you observed). Re-soldering them with the aid of some flux-core solder will remedy this kind of defect.

 

[shrtrnd]

I agree. A bad connection somewhere. I've also found that a dirty potentiometer sometimes causes intermittent problems like this. Try tapping the various connections, dials, and switches to localize the problem.