So, today my PM3350 arrived. Just in time to be productive over the easter holidays and also not being stuck with the tiny DSO203, which is great to take quick measurements out in the field, but at home its kinda sub-optimal. Partly because I only have a stand for it made out of LEGO and partly because 2 channels aren't enough to perform all the measurements.
Now to the PM3350 and its quirks:
First it didn't work, because it probably was a bit abused during transit - PowerSupply-Board and the Papst-Fan were loose. One of the retaining clamps for the PSU-Board even sheared off and rattled inside the casing.
That fix was easily done by just pushing everything back in place.
Another rattling-test revealed nothing else, so I turned it on and after some playing with it, I got familiar with the operation and also discovered two problems:
The First one should be easy to fix, as it probably is just a worn out potentiometer that controls the illumination of the grid.
The second one is a bit harder to fix, I think: It becomes noticeable at 0.1s/div and really obvious at 0.2s/div and 0.5s/div Timebase - The horizontal movement of the electron-beam is not uniform! It jitters to the left and right while moving across the screen. I later also noticed this jitter at higher timebase-setting when I fed a signal from the DSO203's signal generator into one of the channels and the scope triggered on it. It's also visible in the digital mode: The waveform is jumping a little from left to right in live, as well as in locked-mode.
I'm guessing that there is something wrong with the sawtooth-generator that generates the horizontal deflection-signal. My first suspect would be old caps on the PSU and the Generator itself.
Is that a good first guess, or am I fishing in the wrong sea here?
Here's a video showing the Problem:
https://youtu.be/IbRcqXXzNHw
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