A few more pictures as a follow-up.
A quick check with random transistors there's room to fit four TO-247 packages besides the hybrid if things come to the worse.
Base and Emitter break-out wires epoxied onto the defective transistor.
Reassembled with a 2SD2059 in place of the bad output transistor.
Good I/V curve on the component tester between +Vcc and output on the removed hybrid.
The amplifier is now working well, without noticeable difference between channels.
The MPX trimmer needed readjusting on the receiver to get stereo.
Anyone know why the service manual mentions replacing R239 from 13k to 24k when IC201 is replaced?
I checked against the voltages given on the schematic with and without muting. The mute line is close to 0V when muted but not close to 5V un-muted (only 2.7V), replacing R239 with 24k allows to get close to 5V, but why replace it only if replacing IC201?
Thanks for watching.