Is this a bad trimmer? No change in volume for make up gain

[PJD3]

Hello there.

There seems to be no change in output level as R8 is adjusted. I've thoroughly checked that settings are as recommended (Ratio and Threshhold are fully clockwise, Mix knob is fully clockwise, and Gain is set at the half way point. Also, lower swith is to the right (hard) and I'm switching between center and right on the top toggle switch.

I've rotated the adjustment on R8 up to 20 times with no measureable or audible change in either center or right with the top toggle. (pad-on-bypass).
I'm assuming that the discernible change in level would occur in the center position as R8 is adjusted. Is that correct? As well, I assumed that "bypass" is what it means literally, and that we would be hearing the unprocessed input signal.

How many rotations do these trimmers have? Are these the "25 turns" trimmers? I would expect to have measured or heard a change in level after 20 turns in any direction.

Any guidance at this point would be very appreciated.

Thank you,

Phil Donovan