DSO4254B channel 2 Damaged?!?

Rob_ITA

I finally found the solution !!
I reversed this feedback resistor between channel 2 and 3.
Channel 2 now has a stable signal with no oscillations. The resistors, after unsoldering them, were the same (~ 806k).
I think the problem was due to a dirty weld.

Performed a correct calibration without errors (now the signal on channel 2 during the calibration was easily aligned with the other 3 channels).

Thanks for the advice and support!