Wednesday, September 12, 2012

PANASONIC PLASMA - TH42PHD5 TH42PHW5 TH-50PHW5 TROUBLESHOOTING




      Plasma display panel unit may develop failure, where symptoms is localized in a particular area of screen.  Almost all plasma TVs have the same problems, irrespective of their brands.  
  1. No picture.  Black screen:  The use of a magnifying glass can help to localize the defective printed circuit board.  Use the magnifying glass to take a close look at the 'pixels' of the screen.

  • If pixels are totally dark, the defect is most likely located in one of the following boards.
  1. SC-Board.
  2. SU-Board.
  3. SD-Board.
Check the status of LED located on the SD board.  If the LED is dark, a malfunciton of 'SC-Board' suspected.
Listen to the 'Buzz" noise of the 'SC-Board'.  If the 'Buzz' noise is not present, a malfunction of SC board suspected.  Check the Scan Pulse waveform at TPSC-1.  Verify the input signals at connector SC-2, SC-4, SC-20 & SC-21.  Verify that the signals of the clock and serial data lines from the 'D' board are present at connector SC20 AND SC21.

No picture.  Black screen:  Use a magnifying glass, and check if the pixels are faintly lit.  If is, suspect the following boards.
  1. SS-Board
  2. SS2-Board
  3. S3-board
  • Check the status of LED located on the SS-Board.  If the LED is dark, a malfunction of the SS-Board is suspected.
  • Listen to the 'Buzz' noise of the SS-Board.  If this noise is not present, a malfunction of SS-Board is suspected.
  • Verify the input signals at connector SS-3 & SS-1.
Horizontal Black bar [Completely dark]
  • If the pixels are totally dark the defect might be to:
  1. SC-Board.
  2. SU-Board [upper half of the screen only]
  3. SD-Board [loser half of the screen only]
If the pixels are dimly lit, the defect is most likely in one of the following boards.
  1. SS-Board.
  2. SS-2 Board [upper half of the screen only]
  3. SS-3 Board [lower half of the screen only]
Vertical Bar:
  • Since the C2 board contains the serial to parallel converters for the picture data, that drive is the portion of the screen.  The most likely cause to this defect can be localized to the C-2 board or the D-2 board.
  • Since C-3 board contains the serial to parellel converters for the picture data, that drive is the portion of the screen.  The most likely cause for this defect can be localized to C-3 board or D2-board.
No OSD, but have Video:
  • Check the signal on the D-1 board.
Burned Image:
  • Activate the scroll bar, or run the set with a 'White' raster for at least 15 minutes.
After image prevention: will continue by next post