McIntosh 2105 - no power from left outputs

[Full disclosure - total McIntosh / vintage gear noob here]

I'm having trouble with a recently purchased 2105, and after lots of trouble shooting, it appears the issue is no power/signal from the left outputs. Right outputs work fine, and I get right/left signal when using the headphone jack (other trouble shooting tests include testing different speakers and speaker wire, adjusting the connection to pre-amp). Iā€™m testing with new B&W 625s, Adcom 565 pre and a CD player from my old system. All of those are working fine.

I've been referring to the 2105 manual throughout and attaching speaker wire to the "Com" and 8 ohms connections on both right and left. (B&Ws are 8 ohms) Anything else I can try before taking it to a repair shop (luckily there's a local guy who services McIntosh gear). Thanks for your ideas!
Given it's age, they typically need electrolytic caps unless you have blown fuses on that channel. They should all be replaced on the driver boards.
Thanks, Hifigeek1. Sounds like a trip to the repair guy is the best bet!