Alpine mrv one channel down

[vincegironda]

I have an MRV f400 with channel 2 down,

here's a list of areas tested so far

no dc on channel 2
no audio when channel 2 bridged with channel 1 via the correct terminals

Input phono's tested for continuity -all good
Input continuity on channel 2 tested up to KIA6259S OP amp

Input switches tested - working fine
Tried pushing board down on various locations with speaker connected to channel 2 it made no difference.

Amp is stable idling fine and plays perfect on all other channels

any help with this appreciated, thanks

 

[Osvaldo de Banfield]

No DC on channel 2 implies bus rails or inside the amp?

 

[Perry Babin]

If you have audio on all 4 outputs of IC301 and 302, do you have audio on the emitters of all 4 muting transistors?

 

[jkrokenberger]

The dual 5W resistors are known to fail or develop cold colder joints.

 

[vincegironda]

Turned out it was cold solder joints on the dual 5w resistors, I had a similar problem with a Sony amp which also had the same symptoms so I re-run the solder on all 4 resisitors and it works fine now.

Thank you all for your replies and input, much appreciated.