Yamaha RX-V450 Home theater amplifier repair

One of my friends brought me the trouble of not switching on.

They have been improving the end-stage for only a year, but this has nothing to do with the mistake.

It's a pretty good device with lot of connectors.

The power supply was OK, the fuses and the wire were flawless.

However, the main relay does not pull it after the main switch is pressed.

Analyzing the wiring diagram, the power circuit uses the 50Hz network as clock signal...

Through a series of capacitors and resistors, the voltage is limited by a Zener diode.

The capacitor was only 4.254nF instead of 22nF, so the amplitude of the clock signal was low ...

I tried to solder a 10nF/400V capacitor.

This worked, so the 22nF has been replaced by two 10nFs.

This will have a longer life span than if there were only one capacitor.

The repaired amplifier is switched on :).