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Trouble Sh ooting

Page 9

A LC502

7. Checking the interface circuit of sync signal

7.1 Checking the control circuit of horizontal sync pulse

Check  the horizontal sync signal on I301

pin 94 TTL level.

OK

NG

Failure point

1) Video cable may have failed.
2) Printed wire broke between P302 pin 13
and I301 pin 94
3) R346, R348 open

4) C372, C373 short

Process "Checking the resolution change IC

movement" section.

Check  the vertical sync signal on I300 pin

44 TTL level.

OK

NG

Failure point

1) Video cable may have failed.
2) Printed wire broke between P302 pin 7 and I300 pin 44

3) FB308, R343 open
4) C369 short

Process "Checking the resolution change IC

movement" section.

7.2 Checking the control circuit of vertical sync pulse

Содержание AL702

Страница 1: ...17 i nch L C D M oni tor AL702 Servi ce G u i d ervice ...

Страница 2: ...wer s upply for LCD module CPU and logic is generated from the power sou rce 2 4 2 I308 3 terminal reg ulator A 3 3V power supply for I306 analog is generated from the 5V source 2 4 3 I308 3 terminal reg ulator A 3 3V power supply for I306 digital is generated from th e 5V sou rce Q302 Q303 ON OFF control for LCD Modu le ON OFF control is performed for power ON OFF and also for the power saving se...

Страница 3: ...LSI peripheral circuit Circuit diagram MAIN PWB I301 MRT V2 gmZAN1 is the definition A D converter LSI The analog R G B signal input entered from the video input circuit is converted into the digital data of video sign al throu gh the incorporated A D converter Bas ed on this conv ersion this device performs interpolation during pixel exten sion The source voltage for this device is 3 3V and the s...

Страница 4: ...c signal presence of the horizontal or vertical sync signal and the discrimination sig nal HSYNC_DETECT VSYNC_DETECT nWhen the mode has been identified through the measurement of horizontal and vertical frequencies the total number of lines is determin ed with a formula of Horizontal frequency Vertical frequency Total number of lin es Fin al identification can be made by examining the coinciden ce...

Страница 5: ...ey P1 2 4 I switch input key Polarity Mode No Resolution H freq KHz Band Width MHz H V 1 247 VGA 720 x 350 70Hz 31 47 28 322 2 102 VGA 720 x 400 70Hz 31 47 28 322 3 103 VGA 640 x 480 60Hz 31 47 25 175 4 182 MAC 640 x 480 66Hz 35 32 24 5 173 VESA 640 X 480 72Hz 37 86 31 5 6 109 VESA 640 X 480 75Hz 37 5 31 5 7 104 VESA 800 x 600 56Hz 35 16 36 8 116 VESA 800 x 600 60Hz 37 88 40 9 110 VESA 800 x 600 7...

Страница 6: ...uired 9 4 Control of definition converter LSI I300 9 4 1 Ports related to control Pin No I O Signal name Function 159 I IRQ interrupt signal 5 I O SCL serial clock 6 I O SDA serial data 9 4 2 Functions Major function of I300 are as follows 1 Expan sion of the display screen 2 Timing control for various signal types 3 Power supply sequence LCD panel 9 5 I2 C bus control 9 5 1 Related ports of I303 ...

Страница 7: ...Power ON sequence When the POWERswitch is pressed the POWER OFFsignal is turned H When this H potential is detected the CPU begins to establish the respective powersupplies according to the sequence shown below POWER PPWR D SHCLK INV_EN LED DATA ...

Страница 8: ...nce When the POWER switch is pressed while the power su pply is ON the POWER ON signal is turned H When tshown below his H potential is detected the CPU begins to turn off the respective power supplies according to thesequence POWER PPWR D SHCLK INV_EN LED DATA ...

Страница 9: ...e CCFL curren t from feedback The n on inverting reference pin 10 of I102 is at 1 25V nomin al 10 3 7 Protection Open lamp protection in the ignition period is provided through both pin1 and pin 2 of I102 Removal of th e CCFL during normal operation will trigger Q104 to turns on and shu ts off the inverter This is latch function 10 3 8 Output drivers The configuration prevents any shoot through is...

Страница 10: ...mputer is output and if the video cable is connected normally No Proceed No OSD display section OK Proceed Checking the resolution change IC movement section NG Input the sync signal of computer or change the cable When a signal isn t being inputted it is indicated with VIDEO INPUT It is indicated with OUT OF RANGE at the time of the frequency that it can t be distinguished ...

Страница 11: ...ls NG Refer Checking the backlight unit section OK Check OSD menu is displayed on screen when you push the PROCEED key NG 1 Change pattern of video signal output on the host 2 Reconnect the video cable 3 Change the video cable Check the video cable for failure Check the host for output signal with all black only OK NG Proceed Abnormal screen section Next Page ...

Страница 12: ... P303 pin 44 OK NG Failure point 1 I300 failure 2 Printed wire broke between I302 and P303 pin 44 Check the H sync pulse of negative polarity is output on P303 pin 38 at TTL level OK NG Failure point 1 I300 failure 2 Printed wire broke between I300 and P303 pin 38 Check the V sync of negative polarity are output on P303 pin 40 OK NG Next Page Failure point 1 I300 failure 2 Printed wire broke betwe...

Страница 13: ...G Failure point 1 I300 failure 2 Printed wire broke between I300 and P303 pin 42 Check the data signal output on P306 and P303 R G B data pin OK NG Failure point 1 I306 failure 2 Printed wire broke between I300 and P303 P304 data line Failure point 1 The cable broke between P303 P304 and LCD module 2 LCD module failure ...

Страница 14: ...gh level OK NG Is a H level being output in the TTL level from I300 pin 143 Or is INV_EN signal of the rectangle being output NG Failure point Printed wire broke between I300 pin 143 and I307 pin 5 Check the PWM signal of the input from I303 pin 7 is a BRI signal OK NG Failure point 1 Printed wire broke between I303 pin 17 and I307 pin 3 2 I307 failure Failure point 1 Inverter cable disconnection ...

Страница 15: ...e and P303 P304 2 I317 failure Check the negative horizontal sync pulse output to P304 pin 38 from I300 pin 80 at TTL level OK NG Failure point 1 Printed wire broke between I300 pin 80 and P304 pin 38 2 R351 open Check the negative vertical sync pulse output to P304 pin 40 from I300 pin 75 at TTL level OK NG Check the positive DE pulse output to P304 pin 42 from I300 pin 74 at TTL level OK NG Chec...

Страница 16: ...OSD display OK NG Check the input of pulse from I300 pin 5 6 Proceed Checking the resolution change IC movement section Failure point 1 Printed wire broke between I306 pin 5 and I303 pin 9 2 Printed wire broke between I306 pin 6 and I303 pin 8 ...

Страница 17: ...f serial data on I305 pin 6 synchronize SCLK at TTL level OK NG Failure point I305 failure Failure point 1 The host machine isn t communicating in DDC2 mode 2 The video cable may have failed or may not to have connections for DDC 3 Between I305 pin 6 and P302 pin 15 may have failed 4 R337 open 5 Cable failure ...

Страница 18: ...rinted wire broke between P302 pin 13 and I301 pin 94 3 R346 R348 open 4 C372 C373 short Process Checking the resolution change IC movement section Check the vertical sync signal on I300 pin 44 TTL level OK NG Failure point 1 Video cable may have failed 2 Printed wire broke between P302 pin 7 and I300 pin 44 3 FB308 R343 open 4 C369 short Process Checking the resolution change IC movement section ...

Страница 19: ...cuit section OK NG Is 12MHz clock output from X300 at TTL level OK NG Failure point Print wire broke between X301 and I300 pin 3 Failure point X300 failure Is 5 0V supplied to I300 pin 2 at High level OK NG Check the output of 5 0V H pulse from I302 pin 6 OK NG Is 5 0V supplied to I302 pin 7 Failure point I300 failure Failure point Print wire broke between I302 pin 6 and I300 pin 2 OK NG Failure p...

Страница 20: ...er 10V or not Check F801 D801 P801 and repair them OK NG Check pin 6 of I801 have same pulse or not Check R805 R803 I801 and repair them OK NG Check pin 1 of T802 have same pulse or not Check peripheral components of I801 and repair them OK NG Check peak voltage of R811 triangle pulse is up to 1 volt or not Check Q803 R813 R814 D806 R812 and repair them OK NG Check D809 D810 C816 C821 T802 have sa...

Страница 21: ...ower on II Check the 5V power is supplied from power source OK NG Failure point Power source failure Is LED turned on in amber momentarily when a power button is pushed OK NG Failure point Power source failure Proceed Checking the operation of CPU ...

Страница 22: ...the output of 3 3V line voltage from I308 pin 2 OK NG Is the output FB321 being inputted to I308 pin 3 OK NG Failure point Printed wire broke between I308 pin 3 and output of FB322 Failure point I308 failure Failure point Printed wire broke between I308 pin 2 and I300 power supply pin ...

Страница 23: ...Printed wire broke between output of FB320 and I300 power supply pin Is 12MHz clock input to I303 pin 21 and 20 at TTL level OK NG Failure point X301 failure Check the input of 5V H pulse from I310 pin 4 are same as I303 pin 10 14 msec Typ OK NG Failure point 1 Printed wire broke between I310 pin 4 and I303 pin 10 I303 failure ...

Страница 24: ...udio cable disconntction OK NG Failure point 1 Printed wire broke between JK011 pin 2 3 and I001 pin 4 9 2 R040 R041 open 3 R042 R043 short 4 C040 C041 open Is output wavefrom being outputted in I001 pin 14 17 OK NG Is 15V supplied to I001 pin 15 16 OK NG Failure point 1 Speaker cable disconnection 2 Speaker failure Proceed section 9 1 No power on Is mute STD BY low level at pin 11 pin 12 OK NG Pr...

Страница 25: ...em OK NG Check pin 18 of I102 is triangle pulse Check Q106 D110 and repair them Check pin 4 of I102 there is soft start edge up to 4V and pin 11 12 19 20 there is some pulse output Check C115 R108 I102 and repair them Check pin 2 of I102 there is up to 2V from output detection Repair I102 Check full bridge I101 I103 D102 D103 C123 C125 work right Check Q102 Q103 CR101 CR103 and repair them Repair ...

Страница 26: ...e check BOM to get the last release part number and related information No Location Part Number Description 1 I300 6447000406 IC MASCOT II CONTROLLER 160P PQFP 2 I301 6447000506 IC VITESSEI 100P QFP 3 I310 6446008108 IC NC7SZ04M5X SOT 23 5 4 I304 6448016508 IC EEPROM 24LC16B SN SOP 8 5 I301 6447000506 IC ASIC VITESSE2 100P QFP 6 I307 6442001978 IC LM358DR 8P SOP 7 I308 6442023326 IC AIC1084 33CM 3...

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