Transformer alarmingly hot


2013-06-11 3:39 pm
Testing a supply board for a tube I/V - the 12V filament heater rail make the transformer get very hot very quickly. I have tried with two different transformers and the same.

So what issue would make a transformer heat up alarmingly quickly, the transformer is sufficiently rated with 2A for the 12V windings but there is no final load attached just the initial diode and regulator dropout.