Today we have another issue that could be a little tricky to diagnose. The TV seems to have power but just wont fire up!
Television: 55-inch 120Hz 1080P LED HDTV
Model #: DWM55F1Y1
Symptoms: TV will not come on, the indicator light switches from red to blue but nothing else illuminates.
- Since we know the screen should light up after the indicator light switches from red to blue, lets check if this is a backlight issue by taking a flashlight and point it towards the screen to see if an image is there. No image on our end.. This means we have no picture and no backlight present. Well you know what this means… Time for a little surgery!
- By now we all could accomplish this step in our sleep but just in case you have forgotten, lets take the back cover off of the TV and double check all the connections. If everything is nice and snug like on our set then it’s time to move on the the nitty gritty of this problem.
- In many of our previous repairs with similar issues we know that this could very well be a power supply issue so lets start there. Take a voltage reading on connectors 5 and 6 while the tv is plugged into an outlet, we have a reading of 84V, a little low but that would’nt be the reason we have no image on the display.
- Next check the “backlight on” signal at connector 4 on the PSU. On this connector we should be reading 5V from the main unit but nothing there.
- We have finally tracked down the culprit. The Main Unit seems to be faulty because it it failing to send a signal to the power supply to activate the backlights. So lets locate and replace the main unit.
- Mission Complete! We fired the TV right up and everything was back to normal.
Solution to Repair: Replace the Main Unit
Board Responsible: Main Unit (Part # 890-M00-06N74)