I bought one those little JYE Tech DSO150s not that long ago. I know, I know. But I'm a beginner and for my basic audio needs I think it's a perfect little piece of kit. Anyway, I was using it this afternoon and it started showing really weird values. I was trying to measure a 4.5V bias input, but the DO150 was showing me -50V. I verified that the bias really was 4.5V using my multimeter. If I try to read the 9V from my power supply, it acts like it's reading a changing AC current and the duty cycle races up from 50% to 100%. It's really weird.
I tried taking it apart but whoever built it, wedged it all together in the case really tightly. I didn't want to accidentally destroy it by taking it apart, it as I was frustrated, so I'll try again another day. I'll try to see if anything obvious is burnt out inside.
No idea what I did to break it, but likely I did something stupid. But that's really annoying.