Your television sounds like the power supply is "tripping" this is a safety feature and is a common symptom of a short curcuit within the secondary power stage,if you send me the make and model i can tell you how to fix it,but you do need to be a competent electronics engineer to carry out such repairs as there are some dangerous voltages within your tv the maximum at c.r.t (tube) which can be in exces of 30,000 volts.Alternativly you shold take the set to your local repairer .
hope this helps.
Doug
September 2003