L-Tec transformer noise?

[Chris Stevens]

Have an old L-Tec 250HF transformer TIG, which welds perfectly, but has a bit of a strange noise internally. Sounds like high voltage current, going to earth or a component which has failed maybe. Its not the HF which is working fine, and I cant see any signs of loose connections, or any sort of sparking (other than across HF gap) when lookin at it with lights off.

Noise is there as soon as arc established, and continues till gas post flow stops. Same on AC and DC, and just wondered if anyone might know what this could be, or indeed if its meant to sound like this? My other LT I had was watercooled and so loud, wouldnt have been able to hear if it had the same sound. Cheers for any help with this one, the set looks very clean inside, and maybe they all sound like this one?

 

[Barking Mat]

I've a similar lump to yours, has it always made this noise? Is it the solenoid on the gas playing up?

 

[Chris Stevens]

Only just tried it after buying a couple of months ago, and yes the gas solenoid sounds just like the type of thing that might cause the noise. Person I bought it from was running from 240v, and maybe they changed something, which doesnt like the 3 phase I am now running it on? Even has the original print manual with it, and welds very nicely.