Thanks for your replies, Hitesh and bennog!
Yes, I’m using the original blue USB cable from the USB isolator to the scope.
The (cheap) isolator is from Olimex, capable to deliver 750 mA when using an external power supply (I have tried both, a wall plug 12V / 1A and a 12V lead battery to reduce AC coupling to mains).
The crash (connection disruption, scope reset?) happens immediately when changing the time-base, I think before any attempt to switch the relays (a power peak) occurs.
Using Windows, the “Check for Updates” stated “You are using the latest version”, however, today I’ve updated to the 126.96.36.1992
- and this actual version solved the issue under Windows
No more crash, reset, or whatever, I think it works with the USB isolator (need more time to test, but I’m confident).
So it remains a problem with the OS X version only, maybe you could check that for the next version (I’m on an iMac, would love to run my scope without the Windows - VM).
Yes, a USB 2 would be better, but which one?
Best would be a Pico - Isolator! (why not?)