Suddenly very distorted traces

[gundelgauk]

Hello,

after I finished my DSO138, it worked quite well. Now I had it lying around for a few months because I had no projects to work on. Yesterday I tried to use it and I got almost only distortion and no usable trace. So I tried to reset and re-calibrate, but no matter what I do, I get a strongly distorted trace. I'm uploading a picture of the test signal trace. The square wave can be seen, but also lots of distortion.

I measured all the mentioned test points in the manual and in the AV- thread. They all seem to be reasonably close. I don't have the exact values handy, but if it helps I can get them again and post them.

I'm not yet very good at soldering, so it's quite possible that one or several solder joints are bad. But before I re-solder everything, I wanted to try and ask if anybody had any advice for me, which component or area to search in. So I would be thankful for any ideas or hints.

Regards

[gundelgauk]

Luckily I was able to fix it. I just improved lots of solder joints, concentrating especially on capacitors which I somehow suspected. After some other problems with the voltage being completely off, it works again nicely now. Sorry for the superfluous thread.