PLASMA TVs FAULT FINDING AND REPAIR
PLASMA TVs - 1
How these Plasma TV screen works?
The idea of plasma display is to illuminate a colored gas, like Neon or Xenon. You see on the screen is these burning gases between two pieces of glass. The screen has a complex structure, has millions of pixels, and each pixel is powered by tiny electrodes and has its own gas and color. The Plasma TV problems, starts with its screen itself. If plasma screen is broken, there is no repair other than replacement. It has a protection screen in front of it. If the protection screen has broken, can be replaced, and won't cost more. But with actual plasma screen, the things are different. It will cost nearly to the cost of a new TV, including service charges. Plasma screen consists of two pieces of glass with gas in between them, as stated above. The gas is not re-chargable. These gas pixels are controlled by small electrodes. Each pixel contain three colored sub-pixels (Red, Green and Blue). Plasma screen works in two steps. Gas Ignition, and Picture development.
- The ignition is controlled by Power supply, Logic control, X Sustain or Z Sustain boards and Screen.
- Picture is developed by Power Supply, Video control or scaler board, Logic control board, X Sustain board, Y Sustain board, Buffer boards and Screen.
Common problems seen with Plasma TVs are, Flashing Dots or Pixels, when the screen is cold. This is the symptom of bad screen.
Colors are distorted to some parts of the screen. Again bad screen.
Vertical lines on picture.
Flashing red dots on some part of the screen.
POWER SUPPLY REGULATOR BOARD FAULTS.
Main symptoms are:
- Flashing Pixels on the screen.
- Turn ON, but no Video & Sound.
- No Power.
- No power light on front panel.
- Hard to turn ON.
- Turn ON after a long period of time. Sometimes takes 30 minutes or so.
- Turn ON, but turns OFF automatically.
These faults are related to the Main Power Regulator board.
See the picture of power supply regulator board to Pioneer Plasma TV. The type may differ model to model.
Usually, power regulator board can be located at the center portion of the panel. See its location.
Here you can locate it at the center part of the plasma panel.
Power supply boards are very difficult to repair, because, most of the
components used will be very difficult to get from open electronic spare
part market. Sometimes, the cost of component and service charge may
go up to a new once's cost. It will be best to replace it as card
basis. It might cost between $40 to $60. Can bought either electronics
spare part shops, locally, or from the authorised service center for
the TV.
Possible Faults
- Flashing pixels on screen.
- Have audio but no video.
- Vertical color lines on screen.
- Vertical Bars on screen.
- Vertical color lines along with video.
- Picture goes Red predominant after a while.
- Horizontal lines on image.
- Dark image.
- TV turns ON, and shut down.
- Negative image.
- Screen goes black, and come on with picture.
All the above faults are related to either X,Y or Z sustain
boards. These boards look different to models to models, and
manufacturer.
This is the picture of X- Sustain board of Daewoo Plasma TV.
This is an other X-Sustain Board.
Y-Sustain board the likely to be more faulty, than others.
There are buffer boards to this Y-Sustain board. If Y-sustain board
found faulty, it is a best practice to replace these buffer boards along
with it, because, damage to Y-Sustain board might damage these boards
too. There are two buffer boards. Replace these two boards along with
Y-sustain. There is no way to check these boards by normal methods. If
one among the board is faulty, it will effect the replaced Y-Sustain.
Like X-Sustain board, Y-Sustain also differ in size, structure to models to models.
See the picture of Y-Sustain of a 50" Plasma.
This is the picture of an other Y-Sustain board.
This is the picture of the buffer boards to Y-Sustain. One is used as Upper buffer, and the other is Lower
In this picture you can see the location of these boards.
This is the picture of Z-sustain board.
Here the picture of Z-Sustain board to LG 50" Plasma.
- No video, but sound is OK.
- Part of the screen blank.
- Left part of the screen is blank.
- Vertical and Horizontal lines on the screen.
- All Functions not working.
- Some functions are not working
This is the picture of Logic control board to LG plasma TV.
Other faults due to damaged Buffer board are:
- Turns ON, and shut down, No audio or video, Vertical black bars on the screen, Vertical color line size changes, Burning smell, White or colored horizontal lines etc:
- Grey colored screen with no video, and the set refuse to turn OFF. Have to unplug the set from AC mains to turn it OFF.
- No Menu or screen shots. Switches OFF for no reason.
- No video from any one of the inputs.
- No picture to some channels. Only snow is visible.
- No picture, but menu window OK.
- Picture distorts after a while, and sound too seems troubled.
The above stated are the symptoms of faulty Audio/Video Main Board.
This is the picture of a typical audio/video main board.
See its location. The location may differ set to set, and model to model.
Plasma Panel Faults:
- Dark or Burned image on screen.
- Previous screens' static image stays for a while, and goes out after some time.
- Intermittent color change along with brightness.
- Burn in image.
- Turn ON and Shuts Down. This may repeat.
