Sir Rick 79 . . . . .
After having now seen all of the "front end" transistors from this units LEFT CHANNEL having progressively been tested from Q601-3-5-7 and 9 . . . . . all inclusive.
(And little D605 . . .saying me too . . . .ME TOO ! )
The most likely suspect now for a transistor fault would be the Q601 Q603 pair since they are a complementary pair that have the lowest V CBO*** specs of the set of 5. With a breakdown spec of`~ 65VDC.
The Q605-7 and 9 are being up in excess of 100VDC on their VCBO high-voltage ratings specs.
( Our power supply's total summed differential voltages only add up to ~90VDC.)
*** VCBOis the maximum specified voltage threshold, above which, a bipolar transistor could avalanche / break down and conducts between its collector and emitter.
A simple matter of testing now might be the use of the units properly operating RIGHT channel.
Power up and spot check the common shared emitter resistor junctions of R646-648 with reference to chassis ground It should STILL be right at 0 vdc.
(Whereas . . . .I believe that you found this voltage being in the order of 11VDC on your currently BAD LEFT CHANNEL section, on its equivalent emitter resistors.)
On the safe side, in case parts get flying around back and forth, put a dot of red fingernail polish on those just mentioned 5 transistors associated with the BAD left channel.
Test time:
Take your presently pulled Q603 and pull its Q604, like counterpart, on the RIGHT channel and install your now loose Q603 in Q604's place.
Power up and see if the emitter resistor junctions of R646-648 of the RIGHT CHANNEL are still holding, OR if they have NOW developed a noticeable offset voltage presence . . . .such as your BAD left channel had with its improper 11VDC presence...
If no effect at all, that now tested Q603, being used in the Q604 position must NOT be at fault, so pull the Q601 of the left channel and install it in place of the Q602, of the RIGHT CHANNEL which gets pulled.
Power up and see if the emitter resistor junctions of R646-648 of the RIGHT channel are still holding with no change at ~0 VDC.
In this prescribed testing manner, you can clear Q601 and Q603 of the left channel of not having failure due to a lower VCBO breakdown than their specs.
Since . . . . . . they had no adverse effect on the RIGHT CHANNELS operation.
If the RIGHT CHANNEL emitter resistor junctions of R646-648 shifted to BAD, a VCBO spec decline of either of the subbed in left channel transistors that were then used in the Q603 or Q604 positions was / were being at fault.
Thassssit . . . . .
ADD ON:
Just NOW read as far back as # 69 and caught the short statement by Sir Sunnysky.
My off the cuff statement above, entails the specific logic of those parts suspicions.
73's de Edd