UR44 Input Ch 4 is attentuated 15 dB

I’m completely stumped. Somehow Input Ch 4 is killing its input signal by 15 dB. What’s worse, it clips the signal
starting at -15 dB (compared to where Ch 3 clips), but the Ch 4 clipping LED does not indicate clipping.

I use Ch3 Ch4 as a stereo input to my synthesizer, but it’s effective only passing thru Ch 3 to recording and output.

Any ideas what could be wrong? I tried restoring to the initial settings (in UR44 dsp44fx program), but no help there.

I’ve had the unit a little less than 3 years.

Just to add, I remember dropping it accidentally from a height of 80 cm (30") onto a stone floor. This was about a year ago.

RESOLUTION:

I bought a used replacement UR44, and it fixes the problem. Lesson: don’t drop electronics on a stone floor.