Yamaha CP-70B Tremolo Issue

[Jimmyjam]

First post! Glad to be a part of this forum and excited to learn more about my new (to me) instrument.

Here's the symptoms:

Output channel 1: There is no tremolo effect when the switch is turned on. When tremolo switch is both engaged and disengaged, as I increase the depth control pot, the output channel gain decreases significantly.

Output channel 2: works perfectly.

When using two amplifiers, output channel 1 and output channel 2 behave the same as described above.

Pots and tremolo switch have been cleaned.

I was planning on pulling the board, recapping it, replacing the 4558 dual op-amp, and check for cold solder joints.

Does anyone have any useful information not found in the schematic or advice for me before I get started?

Thank you!! Cheers!  - Jimmy

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