Microwave voltage?

Question

Electronics

I got to the LG microwave that had been lying around for a long time. Once it sparked and was no longer used. He opened it, degreased everything, replaced the mica, the cap on the magnetron with a small hole and hardened. I bought a new one, but it didn’t fit, as a result, I found information that the old one can be cleaned and turned 180 degrees to put on the magnetron.
Collected, put a container of water and warmed for 1 minute. The water warmed up and everything went well. But I decided to check with an indicator screwdriver for 100-500V the presence of voltage on the microwave housing and the indicator turned on.
During operation, there is voltage on the case, after it finishes heating, the voltage remains.
The socket is not grounded and the microwave too, but there should be no voltage on the case
I thought when voltage is applied to the case, the fuse should burn out? But he is whole.
I checked the input capacitor of the magnetron with a multimeter, there is no breakdown, everything is fine.
There is a grill in the microwave, ten can be the reason?
I think maybe because of the high-voltage diode connected to the case? But if the diode breaks down, the microwave should not function as I thought? And I don’t understand why the high-voltage diode is connected to the case?

Forgive the help, it is very necessary to understand, first of all, to understand for yourself.

Answer 1

At the input of the microwave there is a noise-protecting filter, in the circuit of which there are 2 capacitors connected in series. The other ends of the capacitors are connected respectively to the "zero" and "phase" wires. As a result, if there is no euro-socket, or a "grounding" wire is not connected in it, then there will be half the mains voltage on the microwave housing (computer system unit, washing machine, etc.). This must be borne in mind if it is possible to touch the microwave housing (etc.) and the water supply or heating pipe (battery) at the same time.