Thanks to all of you for the advice and feedback. I went ahead and placed the capacitor according to the spare parts board, I think that placement was consistent with Martin’s advice. I had some confusion tracing the circuit.

The receiver is now working, and I am not connecting a turntable to it anyway so maybe the polarity is immaterial.

Not an audiophile receiver as Martin pointed out, but a nice unit to have as a secondary sound system.

Happy Holdays!