Apparently same as RX-V681/RX-V781/RX-A760/RX-A860
Everything working fine when plugged in and turned on.
Output voltages on all speaker terminals are few mV.
As time goes by (10-20 minutes), FR chanel goes to 10mv>100mv>200mv>300mv and up to 3V and then PROTECTION kicks in.
Very strange issue. Can't find anything blown/overheating/shorted/open.
All diodes and transistors checking out OK. Resistors too.
Can't find service manual or schematic....
Any help is greatly appreciated.
Everything working fine when plugged in and turned on.
Output voltages on all speaker terminals are few mV.
As time goes by (10-20 minutes), FR chanel goes to 10mv>100mv>200mv>300mv and up to 3V and then PROTECTION kicks in.
Very strange issue. Can't find anything blown/overheating/shorted/open.
All diodes and transistors checking out OK. Resistors too.
Can't find service manual or schematic....
Any help is greatly appreciated.
Did you check the capacitors relating to it ?
I can see why the owners manual doesn't show a circuit diagram this is no simple amplifier ,it has firmware and a host of facilities including video-remote etc etc.
Yamaha TSR-7810
I can see why the owners manual doesn't show a circuit diagram this is no simple amplifier ,it has firmware and a host of facilities including video-remote etc etc.
Yamaha TSR-7810
From one of the pictures on the one of the manuals it appears to use class B output stages without thermal compensation (perhaps that's done in software?). There are two 3-pin output devices per channel only, nothing else on the heatsink.
How this affects offset voltage though is a mystery, but perhaps the way the bias is maintained has a fault on that channel?
How this affects offset voltage though is a mystery, but perhaps the way the bias is maintained has a fault on that channel?
Can find most Yamaha service manuals for stuff that's a few years old or older, assume this is a fairly new model?
Have dug through Yamaha service manuals for units over the past few years, pretty similar basic designs and simple power amps.
My first guess would be something like the input capacitor or feedback capacitors on the amp being bad - maybe just electrically not physically - so would need a proper ESR test to confirm.
If everything is visually okay, and if you are certain electrolytic capacitors are ok and not failing in some way, then would look for dry joints.
Have dug through Yamaha service manuals for units over the past few years, pretty similar basic designs and simple power amps.
My first guess would be something like the input capacitor or feedback capacitors on the amp being bad - maybe just electrically not physically - so would need a proper ESR test to confirm.
If everything is visually okay, and if you are certain electrolytic capacitors are ok and not failing in some way, then would look for dry joints.