I have had the same blown power supply on a DSO-X 2012A, and replaced with a Mean Well RPS-400-12 following the advice above.
However now I am getting a ~120mVp-p ripple @~4kHz on the scope trace, even with the probe shorted to ground.
Have I done something wrong here, or are these power supplies much noisier than the original? I don't remember what I used to get but surely it wasn't this bad?!
Cheers
Hi! I had the same issue when I changed the power supply to one without sense inputs. The ripple was not that bad, but it was very disappointing as it would mean I could not use the oscilloscope. I remembered that in threads where people fixed the original PSU, the voltage was 12.7 or about that. Also, the PCB of the oscilloscope is marked with +13V, where the PSU output is fed into the oscilloscope. I turned the voltage to +13.0, and no ripple was seen.
Last, I checked with a lab supply with +12V. The ripple was not as bad as with the AC PSU, but it was still clearly visible. I guess the lab supply does not handle long wires well when the currents are about 5A.
Thanks, everyone, for your help. I was about to yield to Keysight and their 4200 EUR for the fix they offered.