Colour TV output voltage after power on is 45-55V with impulse sound & continues upto 15min & becomes normal.?

Question

When my ONIDA MZ20 colour TV is powered on, trere is no raster or sound except a speaker impulse sound at an interval of 15sec, which continues upto 15min after which TV sound & picture becomes normal. Internally DC O/P voltages varies 45-55V, 12-16V, 5-6V & comes to 110V, 24V, 16V respectively after 15min at on load condition. But at no load condition O/P voltages are normal 110V, 24V, 16V respectively. Kindly suggest the cause and fault location.

Answer 1

Your model number and name of TV does not show up on the Internet.  Not sure where it is that you are monitoring your voltages.  Can I assume that your input AC voltage is stable?  My first thought is your low voltage power supply.  Doesn't seem to be any regulation until some time has past.  May be a thermal problem, of sorts, with some components in the power supply.