Heys Guys,
I know this topic has been discussed before, but after reading the comments, I couldn't find the answer I was looking for.
I am repairing a SMPS for a battery jump pack for vehicles. I have found a Mosfet blown & so replaced that and hooked up my Rigol oscilloscope to check the duty cycle. Before I did that, I watched Dave's video on how to hook up the scope. The power supply does not have an earth pin and therefore is isolated. So I thought, "not probs - I'll just hook the earth clip on the scope on the negative on the main filter cap and then just check for duty cycle on the PCM IC. But, all that did was blow the fuse and 2 of the rectifier diodes! Am I doing something wrong? I have used the scope several times (I haven't had it too long) on several amplifiers that I repaired (they had earth pins & so I earthed thru the chassis).
After the video, I walked into the shed with more confidence, but after blowing up the fuse and diodes, I have more questions than answers.
Can anyone help?