yamaha em150 p.a. mixer

[robgrif]

Hi all
myYAMAHA EM 150 P.A. MIXER has a problem
everything functions as it should except Left Channel Monitor Output
is dead
I have tried different cables etc. but no ouput
all other outputs function well on both channels
all inputs function correctly
the amp runs at full power no problem to main speakers
I do not have a schematic for this mixer so I am not sure if the monitor circuit has it's own pre-amp sectiom which is causing this problem on the left channel
the connection wire on terminal at jack output is solid and shows good connection to board and cable output wire
any help would be welcome
thanks in advance
regards
robgrif

[Jazz P Bass]

Please verify that you have signal on the dual/ganged Monitor Out potentiometer.
Without a schematic, your best bet is to trace out L & R from the jacks to the board.
There is most probably an identical circuit for L & R.

[robgrif]

yamaha P.A.

Please verify that you have signal on the dual/ganged Monitor Out potentiometer.
Without a schematic, your best bet is to trace out L & R from the jacks to the board.
There is most probably an identical circuit for L & R.

Thanks for the quick reply
I traced back the left channel as you suggested and found the offending transistor in the preamp circuit showing short b to c no other problem seemed to be present
replaced it with nte 199 substitute could not find any other brand locally supplied
and the monitor left channel fired up

Thanks and Happy Holidays to all
regards
robgrif