Mains hum

[steveandthecats]

The bolts are as tight as I can get them on all the transformers and the choke.

Steve

[bob orbell]

Steve, there is a thread on here somewhere about my KAT 6550, but can't find it, anyhow, I too had a very noisy mains transformer which was only resolved by a replacement, now, shhhhhhhhhhhh can you here that. BOB

[Richard]

There is still a very small mechanical hum but not noticeable as it was.
As a general rule I thought that as the transformers were dipped in something originally , would this not 'dry out' eventually and cause it to rattle... in other words do transformers have a lifespan?

Good so far anyway Steve!

If you're sure the mechanical noise is not coming from the mounting or chassis I'd get the choke and mains TX re-varnished. Modern TXs are dipped in a varnish bath and the air is then removed from the vat so they are "vacuum inpregnated" and the varnish gets into all the voids. When dried this then helps insulation and stops rattling and magnetostriction of the lams and windings.

I'm not sure who made your iron but a local winder would be able to advise or do it. Dave Brooks at Danbury is a very helpful guy, http://www.danburyelectronics.co.uk/