Friday, October 05, 2012

SAMSUNG PL42A450P1XZD PL50A450P1XZD LIGIC BOARD TROUBLESHOOTING

Contn;
                                             [4]
  1. Y-Connector > The connector to output the Y-Drive Board control signal.
  2. LVDS connector > The connector to receive LVDS-encoded RGB, H, V, DATAEN, and DCLK inputs from Video Board.
  3. Power connector > The connector to receive power [5V] for the Logic Board.
  4. X-Connector > The connector to output the X-Drive Board Control signals.
  5. ASIC Chip > The main processor that generates and outputs the logic Drive signal and the address data.
  6. DDR Memory for MENCON > The Memory to save the Address output data to.
  7. SDR Memory for Frame Delay > The Memory to save FCR-applied data to.
  8. GTAG port > The port for uCOM communication.
  9. Start screen Option pin > Select  NTSC / PAL Mode Rolling Option for the initial screen (CN2007).
  10. MICOM Loading 5 pin connector or UART Communication Connector.  > The connector to load the MICOM  drive program by connecting GA-WRITER.  This connector is also used to load and adjust 512k data and to connect the key-scan board.
  11. Flash Memory > The Flash Memory to save the MICOM data.
  12. Buffer connection connector > The connector to output the address, data and control signal to the E-Buffer Board at the bottom.
  13. Operation LED > The LED indicating that the sync and clock signals have been received normally by the Logic Board. [Normal status: It blinks at 0.5 second interval].
  14. Buffer connection Connector > The connector to output the address data and the control signal to the F-buffer Board at the bottom.
  15. V-TOGG > The V-SYNC Output Pin.
                                                           42" LOGIC BOARD
DEFINITION OF A LOGIC CIRCUIT
A Logic Circuit consists of a Logic Main Board, which decodes the video signal encoded on the Video Board, outputs the address data signal, and generates and outputs X, Y drive signals, and an Address Buffer Board and outputs the address data output signal to the TCP IC.
  • Logic Main:  A built-in LVDS for video signal processing  [W/L, Error Diffusion, APC, FCR, etc] adopted and 1 ASIC chip.
  • Outputs the Address Drive IC control signal and data signal to the Buffer Board.
  • Outputs the X and Y Drive Board control signals.
  • Monitors the major drive voltages (MICOM circuit part); detects any surge voltage to protect the drive circuit.
  • Temperature Adaptive Operating Mode [Low temperature | Room temperature | High temperature]; optimizes discharges depending on temperature.
Buffer Board >> Lower Part E-Buffer >> Delivers the data and control signal to the bottom left TCP. [Single Scan].
                            Lower part F-Buffer >> Delivers the data and the control signals to the bottom right TCP.
  • When the PDP and Logic Board are normal, the Operating LED blinks at a half second interval.  In the case, the V-SYNC and data signals are output normally.
CHECKS
  1. Visual Inspection  >>> Check if the operating LED on the Logic Main blinks at a half second interval.  If the frequency of blinking is too fast or slow, it means that the MICOM  has failed to process the data properly.  Therefore, have to re-load the data on to the MICOM.  Load the data using GA-WRITER when the power is connected to the module.
  2. If no problem is found during the visual inspection , check if the drive waveform and address data outputs are normal, using an oscilloscope. {Checkpoint:  The DAMPING R-NET part output of each data output terminal}
  3. If no Drive waveform or address output is measured, means that there is a drive problem due to MICOM  data corruption, which was the reason in the Visual Inspection.  In this case, re-load the data as did in the visual inspection.
  4. When data output is measured, but it is abnormal, and the drive waveform is abnormal, it is probably due to a short-circuit of the hardware.  If the address data is abnormal, the screen may be abnormal due to abnormal data output by an abnormal operation of the DDR memory, due to an abnormal Vref voltage, or screen may be abnormal due to a short-circuit in the ass'y inside the board.  The have to conduct a short-circuit test for each case.
  5. If the Vref voltage [the voltage of the Voltage divider] is lower than 1.25V, check resistance of the resistance output part and check if the circuit is normal.  If the Vref voltage is normal,  the screen operates normally.
  6. If the screen is abnormal, even though the Vref voltage is normal , check if there is a short-circuit by conducting a short-circuit test.  If short-circuit is found is an internal one, replace the board.  
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