We have replaced the psu ,mainboard and t-con boards for the above model tv but it does not come on.Do you know how to remove any protection mode the tv might have? we have the remote for the tv. Than

It's possible that the issue could lie with either the T-Con board or the mainboard. However, it's difficult to determine the root cause without physically examining the TV and conducting further tests. Here are some steps you could try:

1. Check for any visible damage to the T-Con and mainboard.
2. Check the connections between the T-Con, mainboard, and power board to ensure they are properly seated and secure.
3. Replace the T-Con board with a new one and see if that resolves the issue.
4. If replacing the T-Con board does not resolve the issue, consider replacing the mainboard.

It is recommended to seek the assistance of a professional repair technician if you are not familiar with electronics repair or are unsure of how to perform the steps listed abov

hi there, can you explain why you replaced the mainboard and psu ?

Does the tv screen flash on and off very quickly? Does the led standby light come on and then slowly blink twice and go out?If these are the symptoms then it is more than likely a bad led backlight strip.I have answered this question in a previous post but to re-cap.I have a lg 47ln540v led tv and had this fault. In the previous post I explained that I had replaced all the boards,main,psu and t-con and all to no avail.I checked as best I could all the solder joints,resistors,fuses etc.I couldn't see any bad capacitors and I was on the verge of giving up.This was all a bit daunting since I am not a tv technican but I am familiar with electricity at a basic level.I decided this thing wasn't going to beat me so I decided to strip the tv screen assembly apart.I checked the led strips with a battery and found one led wasn't working.I managed to source a replacement led strip from a tv repair shop from a damaged tv and replaced it and this solved the problem. As I understand it,if the circuit component that monitors the backlight function detects a fault it shuts off the power to it and goes into a "safe mode",presumably to protect the remaining leds from receiving to much voltage or current since they are wired in series.Incidentally it took me five weeks to troubleshoot this fault.I cannot recommend anyone to do this themselves since there are capacitors on the power board that hold high voltage and charge and can be very dangerous,even lethal even when tv is switched off.I hope this is helpful to someone.

usually bad power supply, Where did you source your part? return/exchange it. Bad LEDs/ possible but not as likely, Tcon working if you can see images with flashlight. You must also have backlight on signal from main board ,check for 3 to 5v on labeled connecter on power supply. UPDATE---47" & 50" LN series. This model has had LED problems if your TV acts as described by Mr. Hughes in is answer to this problem you have bad LEDs

Hello Donald the first thing I would like to Know what the model number of your TV is. But that's ok if you have a external power supply you could try this .Make Shure your TV is not pug In to the Ac outlet. We are going to see if you have a short or a load on your 12v line. Ok you wont to unplug the 12v source from the power supply board. Fine out what pin is the 12v's. Connect your external power source to that pin, apply the 12v and see if it is drawing to much current. If so check the boards for any very hot items. If you have a problem on the 12v line. This will find the part that is loading it down. This is the old way of finding a load on a power source. I hope this will help some. P.S make Shure there is no AC connect to the TV as you do this test and you have the plug off of the power supply board before using the external power source.

TRY T-CON TEST PATTERNS TO ELIMINATE MAIN BOARD

search the model number for t-con test paatterns in service mode

Hi .

The clicks that you hear is an internal device called protection circuit that is shutting down the TV, and forcing the PSU to +5V low only to keep the TV in standby.
That is called protect mode.


If the TV stays in stand-by, with the LED light on, but does not respond to remote, or to the buttons on the chassis, then that means that the TV has gone in protect (safe) mode because an internal fault had been detected.

In that case the TV is usually faulty.

The fuse on the PSU board is not causing protect mode. When the fuse has blown , then the unit stays completely off.

Common faults on rear projection models are Electrolytic capacitors on PSU board (power board), convergence ICs (convergence board). The parts must be tested before replacement. Less common faults could cause the same problem.

Try first disconnecting all connected devices, and leaving the TV disconnected from power for about 30 minutes. To drain power completely.

You cabn follow the basic troubleshooting on this article: Why my TV does not start up and remains in...


If that does not work, contact Sony, ringing the support number listed on the owners manual to get the TV repaired by a licensed technician.

Regards.