I've got a Sola Constant Voltage Harmonic Neutralized Transformer that I use as an isolation transformer when working on TVs. It's heavy enough that my grandfather put wheels on it and a pair of handles to move it around. The fact that granddad did it tells you something of its age. It's always hummed, but the hum now seems more like a roar.
I know old transformers tend to delaminate, but is there anything that can be done to tone it down? When I switch it on, it tends to scare everyone in the room more than the open high voltage in the set under repair.