My name is Nick. I’m a idiotic prideful 17 year old who didn’t think he needed to watch a youtube video before using his dad's oscilloscope. What makes this post more ironic is that I purchased an “oscilloscope tutor kit” which is just a PCB and tutorials to teach me how to use an oscilloscope. Where my trouble came in was it didn’t come with a power supply and it says “9V AC" on the PCB next to the barrel jack.
I found a very old AC bench power supply in my barn and checked it with a multimeter until the voltage read 9V RMS. I cut the end off of an extension cable and soldered that to a barrel jack that fit the socket. This is my first problem – I soldered the ground of the connector to the neutral wire not knowing there was a difference between neutral and ground. After that, having only used a multimeter before, I connected the ground of the oscilloscope lead directly to the grounded outer part of the barrel connector which tripped a GFCI and killed the power in my basement. Being the idiot I am, I reset the GFCI and did it again to the same result. The probe was in 10x mode if that helps at all.
Since it was only 9V RMS and I was in 10x mode on the lead, did I still harm and or destroy my dad's oscilloscope? I am very sorry for the length of this post and how basic it is but I need help.
Best Answer
What I gather from your post is that you connected one of the leads of an auto transformer, which is not isolated, to the oscilloscope ground. The fact that the probe was in x10 mode or even the voltage at which you set the transformer doesn't matter. You created a short circuit through the oscilloscope's ground.
It is imposible to know if it was or was not damaged only from what you said. If it turns on and you can still measure with that channel it is probably fine. If it is damaged, you may or may not be able to have it fixed.
I would definitely recommend talking with your dad about what happened. He can help you determine if there is damage or not, and he deserves to know. Worst case, you made a mistake and have to pay for it. We all do, but at least you can make things right again.