Worried about damaging circuits with my oscilloscope

[emmanuelgoldstn]

Hi all - apologies if this has been covered elsewhere. I did search around for a while before posting.

I just purchased a Rigol 1054Z, and have been anxious to use it to grow my understanding of electronics. My particular area of interest is in RF circuits, so I was using the scope to probe various locations in a TenTec 1054 radio receiver that I built a few years ago. The radio runs off of a 12V battery. I attached the ground clip on my probe to a ground point on the board, and proceeded to probe a few components on the board. Afterward, the receiver seemed a bit more deaf than before, but I may be convincing myself of something that isn't there (this is a receiver for the 20M ham band, and I was testing during a time when propagation starts to drop off). It still tunes, I know the local oscillator is still working (can hear it on another radio), etc.

I watched Dave's video about how not to blow up your scope, and he mentioned floating grounds and being careful where you attach your ground clip. Since the scope is earth grounded, and the receiver uses a floating ground, is it possible to create a potential difference that could damage an RF circuit?

I feel like there are a bunch of things I need to be careful about when using an oscilloscope, but I'm not sure what they are. Am I being too paranoid?

Thanks in advance!

[alsetalokin4017]

It is unlikely from your description that you have damaged anything, unless you somehow shorted something with the probe tip itself (like two adjacent pins of an IC, or similar).

If you are in doubt about the grounds, you can use your DMM to look for any difference between the floating ground of the receiver and the earth ground of your scope probe.

In my experience most LF-HF-VHF receivers work better when they have a good solid earth ground anyway.