Hi,
I'm just having this problem with my Rigol DS1052 oscilloscope. I'm having a bit of a hard time explaining this, but will include all info that I can think of to make it easier to understand.

I was measuring the waveform from a RF car remote control chip when I saw that the triggered signal was tilting downwards at the end. The amplitude of the signal did not seem disturbed, but the 0v pulse marks was negative. I thought it was strange, so I tried to measure a clean regulated 5v DC voltage from my desktop power supply, it dropped almost instantly to 0v.

The waveform on the test-pins on the scope is fine!

When I try to hold the transmit button on the car remote so the scope re-triggers, the waveform looks wobbly and sets at about 50/50 positive/negative waveform. That means +/-6v, since it operates from a 12v battery.

Argh, I don't know how to explain this further, but if you have any ideas, please post them. I will try to capture some example waveforms soon so I can show in more detail.

I do not remember to be messing with any settings other than the ones I am confident in making changes to.

Thank you!

 

The 5V drop to 0V sounds like if the channel you are using is set to AC-coupling.

 

The 5V drop to 0V sounds like if the channel you are using is set to AC-coupling.

You're kidding me. Can't wait to get back home to see if AC coupling is set. Love your avatar

 

Sure enough, AC coupling, thank you for noticing. I know now that it happened when I hit download-button instead of upload-button in scope pc-interface on the settings tab. Should have noticed. Thanks again