The transformer laminations are probably comming apart. Nothing you can do to fix em.
Likely cause is overheating due to overload, lack of ventilation or leaving it on too long.
(Or just crap design / build)
T
There are 10 kinds of people. those who understand Binary and those who dont
It starts buzzin' as soon as its plugged into the mains, so I dont think its overheating... or at least its not overheating now - who knows whats happened in its long and varied history?
So... replacing the transformer... thats the big wirey thingy in the middle?
If I take the old buzzing one into Maplins or wherever, will I/they be able to tell whats a suitable replacement?
I think maybe you need to be a little more certain before messing with 240V supplies What you are hearing is 50 Cycle hum, I think its unavoidable just to what degree it occurs possibly one of these http://www.maplin.co.uk/Module.aspx?Mod ... &doy=16m12
if its a self build maybe put a RCD in there aswell if you haven't got one already.