Power transformer getting 1V?

MyztikJenz

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Donor 5 years: 2021-2025
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Restoring this Turbo Mini and once I got the power all cleaned up and ensured nothing is shorted, it's doing something strange. If I don't have the transformer connected to main power, I read 120V at the connector right before the fuse. However, once connected, I get a reading of 1VAC on the input to the transformer (measuring on the connections of the transformer itself). I do get readings on the secondary winding, which are all minuscule, as expected. The 120V on the secondary reads like 0.3V, for example.

"Transformers [almost] never go bad" says everyone, but is this what it looks like when they do? I'm not getting any smoke, sounds, or smells off of it. It just... isn't getting the right voltage.
 
Might have solved this one, but I'm not sure why. Realized this morning I hadn't connected earth ground to the transformer chassis. Did that and that appears to have resolved the issue. I'm getting good voltages all around.

I'm confused why though. Does the transformer need a proper zero reference or something? The old plug was one of those two-prong jobs that never connected to actual earth and I would assume it was working "back in the day" but I have no way to know for sure.
 
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