The most likely reason for this is puffed up filter capacitors in the power supply.
All modern TV sets (including yours) have what is called a "standby" power supply inside; it is active all the time (even when the set is off) and this is an area where to save money they use cheaper parts.
The caps are rated for a given value and for VOLTAGE; most standby power supplies are about 12 volts although it varies from set to set; put in 12 volt rated caps and the heat from constant use dries them out in a year or two.
The reason this is done is if you make 10,000 sets the difference in cost from 12 volt rated (or less) caps versus 16 or 25 volt rated caps in production is a nice amount of money---they do not care it will fail as long as it lasts at least a year.
This is common also in desktop computer towers: I will attach in a few minutes a photo of typical looking cap----note the top is silver with creases and should be ABSOLUTELY FLAT.
A visual look at the caps on the power board (follow power cord to it) will show if this is the problem; I have had sets where several were puffed up and gradually it got harder and harder to turn set on and or get it to stay on.
Caps that are in this condition will tend to try to work when they get hot, hence after the set is on for a while it stays on.
Buying another power board if this is the problem only buys you some time, it will in the future do the same thing----the solution if this is the problem is to replace the caps with high quality ones rated at a HIGHER voltage-----all the caps will have the value in Uf (micro farad) and the voltage rating (vdc-voltage direct current) marked on them and have a + and - marked for positive and negative side.
The caps are all with 2 leads, with the board out a fairly easy repair--you can see which are bad and the values are printed on them.
SD TECH
141 views
Usually answered in minutes!
×