Shalom Menachem. I've just looked at your profile and note you're in Jerusalem.I've been amused when visiting Israel to find some high current applainces connected using our old British BS546 15 amp plugs and sockets.And landline phones using the same connector as in the UK, though with different pinout as I discovered the hard way.
I've certainly had a Schaffner mains inlet filter fail badly. It was on a Tek 1755A Vectorscope. It got hot enough to melt solder before an RCD tripped.
The question still remains, is the chassis just floating at half mains or is there real current available? Easily tested with a lamp or resistor to true ground or neutral. If there are Y caps in a mains input filter then loss of ground will definitely cause the chassis to float at half mains. Once you're sure that it's just floating rather than with real current available then I'm pretty certain you've got a missing ground. In the scope itself, in the mains lead or at your power outlet.
ppppenguin