Those offset calibration shots at 24 hours are not bad at all considering the input frontend is discrete. You can hardly complain about what looks like maybe half or three-quarters of a millivolt...
Thing is that these offset are there always. And it get's _really_ funny depending on what channels you have turned on and in what sequence. Even worse, the offset and amplitude will change for the same channel depending on what channels were on before and then turned off. Attached are some photos i made (yea, i still have not hooked it up to the computer, sorry). The images where taken after tthe unit was on for about half an hour.
1: Only channel 3 active
2: Again only Ch. 3 active, but after randomly turning on/off the other channels
Note that this is not due to warmup of the scope. After randomly turning on/off channels again it will sometimes fall back to what is in the first image, sometimes to what is in this image, sometimes something else
3: Ch. 3 and 1 on, Ch. 1 being selected. Note how Ch. 3's trace dropped down a bit
4: Ch. 3 and 4 on, Ch. 3 selected. Now Ch. 3 is even further down
5: Ch. 3 and 2 on. Ch. 2 selected. Ch. 3 is now a tad further down even.
6: Only Ch. 2 on. Note the amplitude and offset while it is set to 100V/div (10x probe setting)
Of course after fiddling with other channels it sometimes becomed a thinner trace.
No probes were connected to any channel. All i did was randomly selecting channels, turning them on/off, switching through the V/div settings randomly. Especially the last image shows a real problem: Am i to expect that i have about 20V p-p noise there, with a +10V offset, although nothing at all is connected?
They have a real problem with that offset/cal stuff there. And again, it's not static either, a single channel massively varies depending on what other channels where on/off/selected/etc. previously.
That just ain't right.
Greetings,
Chris