I have a 42PFL3507H/12 Philips TV which I bought in 2012. It hasn't been working fine for a couple of months now. It won't turn on normally when I press the power button either on the remote or on the screen. I have to plug it out of power and back in five to ten times before I can turn it on.
I have searched through the internet but none of the solutions worked. I have tried plugging it out of power and leaving like that for a while. I have updated the software to the latest version. I have even taken it to the certified Philips TV service, but the repairman said that it worked perfectly fine when he tried to turn it on, although he did not show me that it works fine so I'm a bit sceptical because it still doesn't work at home.
What else can I do?
Best Answer
Inside an LCD TV, there are effectively just a few major components:
Some of these items may be combined with others (control board and video board might be the same) or not used (backlight driver usually only needed for CCFL backlights).
Let's work through that list and assess the probability of each component causing the problem you have described.
Your LCD matrix is probably fine. A failure here probably wouldn't stop the TV from otherwise powering on. A failed backlight probably wouldn't either.
A bad power supply might work enough to turn on the red light you mentioned in a comment, but fail to respond to a power-on command. A failed power supply is a likely candidate.
Your TV does not have a high voltage power supply.
The main board is responsible for receiving your power-on command and controlling the power-on sequence. A failed main board is also a likely candidate.
Your TV does not have a separate video board.
A failed T-Con board is not likely to cause your problem. And I don't think your TV has one.
There is a small chance that a shorted speaker is triggering a short-circuit protection mechanism, causing the TV to immediately power off. I would consider this unlikely.
When the TV does work, you state you are able to turn it on using the on-board buttons and the remote, and when it doesn't work neither of them work. Therefore we can rule out the button board and the IR received.
There is a small chance that if you open up the TV and remove the power supply board, you might be able to identify a failed component and replace it. More likely you will have to replace the entire board.