Bad oscilloscope probe does not measure DC

I seem to have messed up my oscilloscope probe during PCB testing. Too high a voltage was applied and there was arcing between the probe and a pin on the PCB. The probe can still read square waves very well (using the compensation terminals on the oscilloscope and a 115V square wave on the PCB.) The problem arises when i try to read a DC voltage.

When trying to measure the switching on of a 115VDC output, I get a signal that rises up to 115V, then slowly comes back down to 0. (The DC source keeps on outputting 115V,1A so the output is definitely active).

Also, when measuring a 12VDC supply, i get the following sinusoidal waveform.

I have opened up the probe and the resistors and capacitors seem fine (no broken chips and no heat traces). I am looking to understand what is happening with the probe and repair it if possible.

The probe model is the RP3500A passive probe from RIGOL.

PS: I have measured the previous waveforms with another probe using the same oscilloscope channel and i get a clean switching on of 115VDC and a constant 12VDC.

Thank you!