Although this is actually specific to a TV, I guess this is just a question about CRTs in general.
My CRT makes a strange staticy/hissing noise, and it appears to come from the back of the tube.
It goes after about half an hour.

Is it on its way out??

Thanks,
Paul

Better start shopping.

thanks for the uber quick reply :P

i had hope till now :P

I have seen (heard) CRT monitor last for years after they start whining - it may last awhile.