Extreme hissing/static sound

[Nipedley]

Hiya guys, I figured a little while ago that one of my LOPT's might have been busted and well this seems like it might confirm it?
It started hissing, like a static sound mid-play a few days ago and I turned it off. Went back an hour later and it was fine, this has been true since - it seems like if I leave it for long enough it sorts itself out but comes back quickly, today I turned it off and on after about 5 minutes and just got an extreme "TSHHHHHHHHH!" so where would this be coming from? The only thing I can think of would be the LOPT but I'm no expert...

[grantspain]

it might be just frequency noise coming from one of the coils,if its ht sparking then it will come from the body of the lopti or the ht cap on the tube-thats easy to prove just see if you get blue sparking from each of those areas.if your picture remains ok when you hear this noise then its likely to be just frequency noise-sometimes you can help this by changing a few of the capacitors on the frame chip circuit,otherwise you may have to change the offending coil.

[SirPeale]

What the heck is a LOPT?  From another post it sounds like a flyback.

[grantspain]

alot of us call them lopti in the u.k but you are correct flyback is the correct terminology,its like some people say condenser instead of capacitor.typical brits eh!

[Ken Layton]

Actually, the correct term is Horizontal Output Transformer (a.k.a. "flyback").

[Nipedley]

Confirmed it was the 20" monitor chassis (the one I just bought, tsk.) so I swapped it out for my previously-prepared chassis and all is well for the moment. =). Still planning on fixing up the top monitor at some point, but for now it will more than do!