but I think your probes are fine. Mine did this thing where once in a while it would drift alot. But that went away. It might be something as benign as moisture baking off the amplifier because it was probably not powered up for a long period of time for god knows how long.
Like those big spikes, I think I had stuff like that too. I was just keeping an eye on it.
I say you can measure small currents with it, if you are fast, and let it warm up, and wait 20 min after the zero pot, but I don't see a big reason not to just zero it on the scope and not use the pot. So long its within ballpark.
Because each time you clip it on, you get a big offset.
Also, try fiddling with the locking mechanism. I put some teflon PTFE grease on the probe head that goes into the sheath, so it runs a bit smoother. I almost feel like that big spike you see followed by stable flat line, its some kinda mechanical thing like the spring shifting or something.
Actually, I am almost sure of it, you need to clean your probe head. The dirty 6042 was doing it ALOT, util I cleaned it good by scrubbing with a q-tip in IPA (anhydrous spray can). Then it was stable without the bumps.
I thought it was like.. some kinda grime being displaced suddnely after it lost some.. corn starch like stiffness parameter.
I found it bizzare becuase it was stable, then shot up by ALOT, then was stable again. Q-tip had grey residue on it.
haha, I was so excited by these probes, then some how they went into disuse.
Problby got pissed because I did not have a VHF power amp to test higher current at high frequency!
What I did is put a q-tip in the hole for the wire, rotated it a bunch to compact it, then retracted the probe half way and spun the q-tip so it wipes the core, then blew it out with air.