Well... time does fly by when you're having fun, doesn't it.
Now... Rigol USA have actually sent me a _new scope_ and I've returned the old one that had the Freeze Bug. They offered to do this, I didn't ask for it originally. I also got them to send me the new one before I would box up and return the old one. So now I'm on the _third unit_ -- the first one had the bad CH4 glitch and was returned to TEquipment the first week I had it, the second one I've been using since April, and now this third one from RigolUSA. It was delivered with the SP1 firmware and the Boot Version 0.0.1.3... so it did NOT have the "freeze bug" which seems to depend on Boot Version 0.0.1.2.
But it still DOES have the Math Trace Horizontal Error Bug at 500 ns/division.
But... in the meanwhile I have noticed that the SP2 firmware does fix some other bugs that I've complained about, such as the "units" of Watts resulting from an A x V trace multiplication not being carried over properly to the Measurements and the All Measure table. And setup files containing Math did not load properly with the older firmware. Since I do use this Power Computation all the time -- in fact it is the most used function for me on the scope -- and I use stored setups quite often, I decided to upgrade the new scope to the SP2 firmware.
And right away I noticed this show-stopper bug. The Measurements simply _stop working_ altogether after some random time interval and there is nothing that can get them started again, except power-cycling the scope !! This happens when there is a Math trace on the screen. And _every measurement_ that the scope can make stops working, not just the ones that might be active when the bug hits. Before I returned the "old scope" (#2) to Rigol I set them up side by side and tested them both simultaneously, and they both did the same thing: the Measurements stop after some random time interval and nothing can be done to get them started again except power-cycling the scope. Once I confirmed that the New Scope (#3) didn't have the Freeze Bug I boxed up #2 and sent it off to RigolUSA for their testing. So now I'm using the #3 scope in my daily work, even though it does have this Measurements Fail bug.
Here are the three videos I've made documenting this new bug:http://www.youtube.com/watch?v=faCNVDCHMbshttp://www.youtube.com/watch?v=MmaWf_33dqghttp://www.youtube.com/watch?v=I6kFfy8sW68
I've reported this to Rigol USA and they immediately reproduced it on their test scopes. So there is no doubt about it, this is not "just mine" that is affected. They are supposedly working on a fix for it, have assigned a Case Number and so forth, so it's an Official Bug that they are trying to fix. EEVblog forum members have also reproduced it. It seems that it is coming along with the SP2 firmware.
The "workaround" for now, seems to be to keep the Math trace turned OFF, and just turn Math on briefly when you need to read or record a Power measurement, then turn Math off again. But work fast, because when Math is turned on it can take just a minute or less for the Measurements to fail, and then you have to power-cycle the scope to get them working again. But also, sometimes it will run on for many minutes, even an hour or more, before the Measurements fail. The time-to-fail seems to be totally random.
So let's keep our fingers crossed and hope for a new Firmware Update "soon" that will fix this severe Measurements Fail bug, the Math Horizontal Error bug, and that stupid "Pluses" typo.