Polaroid LC20H15 Service Manual
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Polaroid LC20H15 Service Manual

Polaroid LC20H15 Service Manual

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LCD TELEVISION
LC20H15

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Summary of Contents for Polaroid LC20H15

  • Page 1 LCD TELEVISION LC20H15...
  • Page 2 Functional Board List LCD/Plasma Televisions Please note that this BOM list may vary from the original documentation. This part list supersedes the parts list contained within the body of the service manual. Please reference the part numbers below when ordering replacement boards of the servicing of this model.

  • Page 3: Table Of Contents

    Safety instructions………………………………………………………………………..… Instructions on adjusting and testing…………………………….…….………………… Trouble shooting……………………………………………………….…………………… Method of software upgrading………………………………………….………………… Briefing on LC20H15 and its working principle………………………………..…………. Wiring diagram……………………………………………………………..……………..Serial NO. of parts……………………………………………………………………….… Identification criteria for the bright spot and dark spot of the LCD screen………..…. Troubleshooting guide………………………………………………………………..……...

  • Page 4: Safety Instructions

    No sound (with TV input as an example) Attention: This service manual is only for service personnel to take reference with. Before servicing please read the following points carefully. Safety instructions 1. Instructions 1.1 Be sure to switch off the power supply before replacing or welding any components or inserting/plugging in connection wire 1.2 Anti static measures to be taken (throughout the entire production process!): a)Do not touch here and there by hand at will;...
  • Page 5 2.9 As most of the circuitry in LCD TV set is composed of CMOS integrated circuits, it’s necessary to pay attention to anti statics. Before servicing LCD TV make sure to take anti static measure and ensure full grounding for all the parts that have to be grounded. 2.10.There are lots of connection wires between parts behind the LCD screen.

  • Page 7: Main Board

    5 Adjustment and calibration for the TV board Connect the main board X501 to infrared receiving board (as per wiring diagram 203-L20H80-01JL) and press the POWER key on the remote control set. Now Now the indication lamp of the infrared receiving board is blue.

  • Page 8: Trouble Shooting

    the output picture from AV OUT is colorless.) d) VGA Interface Input VGA signal(K7253 signal generator). Separately input the four types of VGA format signals as listed in Table 1. Wait till auto calibration is over. Then check if the picture and sound is normal. If there has been interference to the picture then press the auto set key on the remote control once again and check if the display is normal.
  • Page 9 2.TV set: Symptoms Possible cause Unable to switch the power on Check to see if the power plug has been inserted properly into the socket. No picture and sound Check to see if the power supply of liquid crystal TV has been switched on.

  • Page 10: Method Of Software Upgrading

    Blur picture Check if the antenna cable is correctly connected. Of if it has received the right video signal. No sound Check if the “mute” audio frequency setting is selected. Check if the sound volume is set to minimum. Make sure the earphone is not connected. Check if the cable connection is loose.
  • Page 11 Based on the computer features, set up the serial port(COM Port). Select corresponding serial port (if it’s unable to FLASH WRITE, change to another port). Baud is selected to be 115200. Then select Reset Target After Download. Click FLASH pushbutton, it’s ready to run. For other settings, please refer to the Fig.

  • Page 12: Briefing On Lc20H15 And Its Working Principle

    YPrPb/YcbCr,PC VGA port, earphone output and other signal ports. For power supply an externally connected power adaptor is provided. The circuitry of LC20H15 is composed of RF module board, video signal board, digital signal picture processor and AC-DC transformer, and DC-DC circuit board.
  • Page 13 (1). BLOCK DIAGRAM ANTENNA VGA interface...
  • Page 14 Among which: Video decoder: VCT3833 Picture processing: Pw1306 Audio processing: MSP3420 Sound amplification:TDA3002D2 Signal selection:BA7657F LVDS conversion:DS90C385 FLASH memory:M29LV800TTC-90 SRS sound field:M6294E (2). Power supply 12 V is input through power supply adaptor and then is transformed through DC-DC into output of 5 V, which after going through various kinds of three terminal stabilizing integrated circuits, is output as 1.8 V and 2.2 V.
  • Page 15 VCT38XXA/B is a single chip TV processing IC for high picture quality. Modular design and workmanship of sub-micro level enables it to use in all TV equipment. It includes complete display of video format processing. The video front terminal unit provides an analog interface for all video inputs and performs analog-digital conversion for the downstream digital video processing.
  • Page 16 (3).Audio frequency part 1.MSP3450G MSP3450G is one of MSP34x0G series. It is a single chip multi-system processor for sound, which covers global wide analog TV system processing for sound. In the case of NICAM digital sound system, all the TV sound processing from analog IF signal input to AF-OUT (audio output) after processing is performed in this single chip.
  • Page 17 2. M62494SP SRS technology is incorporated in M62494SP. The full name of SRS is sound retrieval system, implying a sound system that can reproduced and restore the stereo sound that is taking place at the site. It is a patented sound technology of SRS Lab USA. The signal is fed to pins 1 and 2 of M62494 through pins 27 and 28 of MSP34x0.
  • Page 18 3.TPA3002D2 Sound power amplification TPA3002D2:(power amplification of stereo category D with volume control) TPA3002D2 is a high efficiency audio frequency amplifier of category D. The gains scope provided is -40dB to -36dB. Supply voltage is 12V. The input of the amplifier is differential input (any noise at the two input sides of the channel can be eliminated).
  • Page 19 (5). Processing of photograph PW1306 is an optimized graph processing IC used for plane displayer (monitor). 1.U12 74LVC541A is an 8-digit buffer. Its input and output have 3 state functions. When OE1 and OE2 are both low electric level, Ii and Oi are in on state. Otherwise Qi is three states. Controlled by RD,CSO signal of PW1306, PW1306 reads the information about the push key and decodes the key according to the state of D0 \ D7.
  • Page 20 PW1306 Memory In Bus Memory Out Bus...

  • Page 21: Wiring Diagram

    WIRING DIAGRAM...

  • Page 22: Serial No. Of Parts

    Serial No. of Parts 335-2000-00 Display screen 203-L20H8-01W Parts of main board 302-AD16A-02 adapter 667-L20H8-05 Parts of big key board 667-L20H8-09 Parts of infrared receiving board 667-L22H8-55 Parts of TV board 667-L20H81-05 Parts of small key board 667-L20H8-55 High frequency board Identification criteria for the bright spot and dark spot of the LCD screen Q’ty allowed Distance between two spots...

  • Page 23: Troubleshooting Guide

    Troubleshooting guide No raster Does the logo appear on the screen Check whether the adapter Check whether X101 is when turning on the set ? supply 12V power to Digital Board. properly inserted. Good Check whether there is R.G.B Check U125965V. Check whether FUSE is melted.
  • Page 24 TV board troubleshooting No picture but have raster. Measure the waveform of R.G.B Hors, Vers at X7. Check whether N1 has Check whether X9 pin 1, pin 2 have 5V power supply. 5V power input. Measure N1 pin 33, pin 35 Replace N2 Replace N1 waveform.

  • Page 25: Exploded Views

    PW130 PW130.SCH RGBSWITCH SDA1 RGBSWITCH.SCH SCL1 LVDSOUTPUT LVDSOUTPUT.SCH RAIN RAIN BUSY GAIN GAIN SDA1 BAIN BAIN FLASHID SCL1 HSYNC HSYNC BUSY VSYNC VSYNC PI5V330A PI5V330A LCDVCC PI5V330B PI5V330B FLASHID POWER POWER.SCH LVDSON HOLD LVDSON LCDON POWER LCDON RESETn TTLOUTPUT TTLOUTPUT.SCH POWER FLASH DRE<7:0>...
  • Page 26 VD104 R125 IN4148 LCDON IRF7307 PGND1 LM1117MPX L107 C122 DVDD1 LVDSON 0.1u STBH-102 VD105 V12-STB Vout IN4148 C121 10V100u C127 R112 0.1u L112 C135 100K L108 R124 0.1u AVDD C128 PGND1 6.8uH 100K STPB-300 10V100u C137 C124 0.1u C123 0.1u 10V100u PGND1 AS2830...

  • Page 27: Schematic Diagram

    VDDQ3 VDDQ3 R223 3.3K L206 FLASHID R225 8.2K X203 3.3uH R224 VDDQ3 V201 R222 BC847 L207 3.3K TVRAIN R221 3.3uH TVGAIN 3.3K VDDQ3 TVBAIN C231 TVHSYNC L208 10V22u TVVSYNC 3.3uH C230 C240 0.1u R214 10V22u R215 R216 V5-1 C232 C211 10V47u C204 0.1u...
  • Page 28 DGO<7:0> DRO<7:0> R330 R331 R329 DBO0 D<15:0> R327 DBO1 DBO2 R328 DBO3 RESET DBO4 R309 DBO5 VDDQ3 DBO6 3.3K DBO7 R332 DBO<7:0> DBO<7:0> R312 DCLK R313 A<19:1> VDDQ3 VDDQ3 R314 R315 DGB6 DRE<7:0> R333 DGB7 L301 DRE0 DRE1 22uH DRE2 VDDPA2 DRE3 VSSPA2...
  • Page 29 VDDQ3 A<19:1> D<15:0> D<15:0> R507 VDDQ3 X501 3.3K VDDQ3 ROMOEn V5-STB BYTE# VDDQ3 VDDQ3 HEADER 4X2 DQ15/A-1 C507 C508 0.1u 10V 47u DQ14 VDDQ3 ROMWEn DQ13 R512 VD501 IN4148 C501 R513 AM29LV800BT 0.1u DQ12 RESET ROMWEn C506 R515 0.1u V501 VDDQ3 RESET# VDDQ3...
  • Page 30 R609 X602 R610 LCDVCC U901 C608 C607 HWJS538 X603 VD901 0.1u 16V 100u C902 C901 BLUE 0.1u 10V22u PGND2 BUSY R901 SDA1 SCL1 X901 CH-- VOL-- VOL+ X604 S504 S505 S507 S506 POWER SOURCE MENU X502 S503 S501 S502 X501 Title Size Number...
  • Page 31 R716 X701 DBO<7:0> R715 DBE<7:0> R713 3.3K DGO<7:0> R714 V704 DGE<7:0> BC847 R717 PGND3 R712 DRO<7:0> C707 2.2K DRE<7:0> 0.1u LM358 VDDQ3 VDDQ3 R709 C710 HEADER 20X2 0.1u R708 DRE0 DRE1 DRE2 DRE3 VD701 C706 DRE4 DRE5 10V 100u IN4148 R707 DRE6 DRE7...
  • Page 32 C122 C121 R125 3.3V-1 100n 16V 22uF R134 AV2-RIN V103 GNDA R123 R124 BC847 VCT3833 MONO R135 LL4148 LL4148 AV2-LIN V104 HFLB SAFETY 50V 3u3 100n 16V 10u 2SC1815 AGND VERTQ VPROT R126 R127 R105 C123 C124 470p C27 470p V102 16V 220u 16V 47uF...

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