Today’s repair features a problem that could seem a little tricky at first to diagnose but with a little guidance we will help you prevail and repair your beloved television.
Television: 43-inch Plasma HDTV
Model #: PN43F4500AF
Symptoms: The TV has no on screen image or back-light illumination present. When the joystick is moved the indicator light flashes as if the television is on.
If you would like help identifying the boards or a further explanation for the functions of each board inside of this plasma television please refer to our Plasma TV Guide.
- To prevent a misdiagnosis lets double check all connections to all the boards. Yes, sometimes the repair can be as easy as reseating a loose cable or ribbon. So let’s remove the back cover and check for any ribbons on cables that appear to be loose or disconnected. If everything is connected properly like on our unit, we can move on to the next step.
- While the television is connected to a power outlet we can see that a green light is flashing and the digital audio out light is on. This means the TV “thinks” that it is on when it is actually off. This narrows down the suspect slightly but we need further testing to be absolutely positive that the main unit is the problem.
- To further narrow the problem down lets take some voltages. Always be cautious when checking voltages on a power supply. The amount of power this board produces can and will cause serious harm if you are not careful. There is a sticker on the panel that states what the voltages should be. Plasma televisions will always have a sticker on the panel containing this information. Remember to take readings while the television is plugged in and “on”. During our measurements, Va had a reading of 58V, Vs measured 209V, and we also have our 15V and 5V. So on our unit the voltages are all great and we can eliminate the PSU as a suspect. If you are not getting the appropriate readings and suspect that this is the evil causing your TV to malfunction you can pick up a new power supply unit and finish your repair. If everything checks out on your power supply as it does on our unit, do your happy dance then move on to the next step.SIDE NOTE: Va and Vs are determined by the Manufacturers which is dependent on gas pressure and current technology of the panel.
- Lets disconnect the Y-sustain and check all of the inputs for a short. Once again, if everything checks out fine then we have successfully diagnosed this issue as a defective main unit.
- Last step is to replace the main unit, make sure all of the connections are still in their proper places, place the back cover back on, and fire the television up and watch your hard work pay off… pun intended.
Solution to Repair: Replace the main unit board
Board Responsible: Main Unit (Part#: BN94-06194X)