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PLASMA TVs [FAULT FINDING AND REPAIR -1]

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.

     Screen problems will be difficult to rectify.  Not difficult, it
is not possible. But panel problems can be rectified.  Plasma TVs are
very sensitve to AC input voltage.  Make sure that the plug you
connected the Plasma TV with wall socket have no sparks or loose
contacts.  Proper cooling system should be installed, if company did not
provided it.  do not leave the TV on only one channel for a long time.
 Change channels occationaly  The power to plasma should be isolated.
 That is, no other load should be taken from the same line to which
plasma TV is loaded.  Unlike CRT based TVS, plasma TVs do not effected
by external magnetic fields. 

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