Power supply voltage to chassis

Amp 20230417_002336.jpg
I have a home theater amp and when I plugged in the RCAs I noticed a tingle hummmm so I measured from the chassis to the ground in the power socket (amp is double insulated therefore it hasn't got a ground on the plug) and I'm getting 100+ volts AC so out of curiosity I measured what it looks like the primary side (to the left of the transformer in the photo) and every one besides the visible blue and white wires is 1ohm or less to chassis, is this normal? I doubt it is BUT the amp is working..... I haven't tested audio yet as I was about to when I got the tingle but it all seems to be working fine when pressing buttons etc....

Also getting 100v from speaker positive to wall socket ground AND the same of the speaker negative.

Any thoughts would be greatly appreciated
 
No, not normal. Look for a failed death cap from line to chassis. Measure DCR from chassis to AC line (line and neutral) - you could have a short in the power transformer from primary to core. (Should read open) If you are not experienced enough to identify the problem the advice above should be followed.

Finally disconnect and do not use this amplifier until you identify and fix the cause of the problem
 
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Australia uses polarized plugs. I'm surprised the fuse didn't blow, though. There should be significant current flowing in the protective earth conductor.

As others have said already: This is not safe. You risk electrocuting yourself if you touch the chassis and something grounded at the same time.

Tom
 
If you measure with a high impedance voltmeter, like 10 meg, it can be normal: it is simply the leakage. You should test the resistance between the chassis and both sides of the mains plug.
If you read infinity, you can proceed with the next test: plug the appliance into the mains, and measure the AC current between the chassis and the earth of the outlet; it should not exceed 200~300µA