When your TV works, has sound, good indicator light but all you have for a picture is a horizontal line across the screen, you have no vertical drive. This can be caused by the IC overheating or a power spike. In addition if you have a newer TV (projector) it may not turn on and will only blink an error code.
This is not a difficult fix but requires patience, good soldering skills and dilligence. Begin by unplugging the set and removing the rear lower area. Around the perimeter of the section you will see screws. Some will have arrows pointing at them. Remove all these screws and remove the rear cover.
Now you should be able to see the entire chassis. It will be mounted on a plastic frame and will consist of two or more circuit boards. The one, usually on the left, will be a small signal board. The one on the right will be the low voltage power supply, high voltage power supply and you guessed it, the vertical drive section.
The vertical IC is located near where the wires from the yoke which are red,green,yellow and blue terminate on the main board. The yoke is a large coil on the rear of the CRT which spreads the beam. It is slid over the glass CRT. Follow the wires (which should be green, yellow, blue and red to the circuit board. This will be the vacinity of the vertical IC. It will be mounted to a large heat sink and generally the designation begins with "LA" followed by 4 numbers. Panasonics generally begin with TDA.
Once located, remove and replace the unit. Removing the unit will probably require removing the circuit board. This involves removing all the screws around the perimeter of the board and any which you find in the center of the board. Do not force it, if it will not move easily look for and remove more screws.
You can get the replacement parts at http://www.encompass.com
. Make sure you clean off the old heat sink compond and reinstall new heat sink silicone also available at the same web site. The heat sink compound facilitates heat transfer to the heat sink and keeps the IC cool. Generally the ICs are run at a high output and get very hot.
After replacement of the IC check all the safety resisters near it for continuity and also any and all diodes for integrity. These parts would be in the vicinity of the heat sink. Removing the IC may require prying it off the heat sink as many times the heat sink compound acts like a glue.
If everything checks ok you should have a working set.
If you do not have vertical drive, you will need a schematic to find the power source for the IC and test the circuit to see if it has the proper voltages.
You can sometimes get schematics from http://www.encompass.com
but they do not have all of them. If you do not mind paying about $16.00 US you can get any service manual from http://www.servicemanuals.net
Once the proper power is supplied to the IC you should have a working set.
Remember to use an isolation transformer anytime you are going to check voltages in the set. Modern TVs have the chassis attached to neutral making a 60 volt difference between the chassis and hot side. This means that if you do not use an isolation transformer and apply a DVM with a low path of resistance you will cause a direct short and blow the fuse, if you are lucky. Also remember to be careful when measuring voltages as there are lethal voltages in a TV when plugged in and running.
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