I have a 60" Hitachi projection TV. A transparent red spot about the size of a tennis ball has appeared on the bottom left of the screen. I thought it was something on the screen but cleaning doesn't fix it.

Any idea what would cause this or how to fix it?

coffee, February 2007

On older units, a possibly cause is mould contamination in the red crt coolant. Especially if the spot appears to float around slightly or intermittently changes position as the TV warms up. A small amount of contamination will appear much larger on the screen.

If this is the case the coolant can sometimes be replaced or otherwise the individual tube replaced.

Cobweb, February 2007