Pioneer SX 950 - does not turn on the right channel.

[Dawid Ratal]

Hello everyone, Have any of you encountered this problem before?

Pioneer SX 950 receiver, serviced. All voltages on the power board are correct. Also the protection plate. No problems with ranges.
Replaced the column switching relay with a new one (Mouser - Omron LY2F-DC24). All switches cleaned (including potentiometers).
But...
After switching on the ampli, the relay clicks turns on only the left channel. However - if I turn it off and on again - all channels play. No problem, and you can listen to music normally.
This happened before the relay was replaced. After replacing it with a new one, it still sometimes won't turn on only the right channel.

Strange situation...

I searched for articles about this, but I didn't see any that had this problem.
The only thing that has not been serviced is the Power Amplifier Board (AWH-050C) - could it be the last one to be the cause?

I will be grateful for valuable tips.
David

 

[kwayde]

The problem could be anywhere. Look for cold/bad solder joints, for cracked traces, and for loose wiring.

 

[HWKI]

Sounds like you had a-lot of work done. If you have access to another amp/ preamp.

pull the two jumpers from back, rca the L/R pre amp to alternate amp. Validate function.

do same with main amp L/R of the sx950 to alternate preamp. Validate function.

Or. If you don’t have access, connect L pre amp to R amp and R pre amp to L amp , does problem move to other side?

 

[aldkiz]

The low voltage signal travels through a number of buttons and switches. Almost any one of the buttons or lever switches that is need of cleaning can cause this problem. The face plate must be removed to properly spray clean the buttons. The back of the buttons are flared. Spraying contact cleaner around the button from the front will get very little cleaner into the switch. The signal travels through some switches that you might think it does not.

 

[Dawid Ratal]

The problem could be anywhere. Look for cold/bad solder joints, for cracked traces, and for loose wiring.

Thank you for your help. Even though all the switches were cleaned - the mono/stereo switch had no contact.
Fixed - works.

Thank you all for the tips. I love this forum!