Yamaha CVP-85A no sound. Similar to CVP-87A no sound

by Neil
(Edinburgh, Scotland)

The fault on my Yamaha CVP-85A is that the panel lights come on but no sound from the speakers or headphones. The Speaker Protection Relay is not getting the coil voltage. I have tested the relay and it does work on the bench. The power amplifier module has Vcc and -Vcc and I can detect the LH and RH audio output at the stereo amp module on a digital volt meter set to VAC. Plugging in a CD player and applying a DC voltage to the coil to operated the relay will play music. I have changed all the capacitors on the PU board, but this did not cure the problem.

Once fixed I will replace all the caps on the DM board as many are leaking dielectric.

Can anyone suggest a PU fix or the root of the problem?