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Acer AL502 Service Manual
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Acer AL502 Service Manual

Acer AL502 Service Manual

15-inch
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A L502
Servi ce G u i d
ervice
15-i nch L C D M oni tor

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Summary of Contents for Acer AL502

  • Page 1 A L502 Servi ce G u i d ervice 15-i nch L C D M oni tor...
  • Page 2 1. Audio circuit (Circuit diagrams Main PWB) 1.1 Au dio in pu t Th e au dio sig n al in pu t recei v ed from th e au dio in pu t termin al (JK011) i s appl ied to th e a mplifi er I001 of 4 (L- CH) an d 9 (R-CH) th rou g h th e low-pass filt er c on sis tin g of R040, R041, R042, R043, C040 an d C041.
  • Page 3 2.7.4 OVP : If +5V g oes u p too mu ch , th e in du c ed v oltag e on p in 4 of T802 b ecomes larg e al so. Su ppose th at it is ov er 18 v olts, ZD801 con du cts, pin 3 of I801 is pu lled u p ov e r 1 v olt.
  • Page 4 8. E PROM (Circuit diagram MAIN PWB) Data tran s fer bet ween I304 an d CPU (Circu i t diag ram MAIN PWB p ag e 4/ 7 (I303) is e ffecte d th rou g h th e IIC bu s SCL (pin 9) an d SDA (pin 8) of I300 o r SCL (pi n 42) an d SDA pin 39 of I301.
  • Page 5 Tabl e 1 Mode VGA 720 x 350 70Hz VGA 720 x 400 70Hz VGA 640 x 480 60Hz MAC 640 x 480 66Hz VESA 640 X 480 72Hz VESA 640 X 480 75Hz VESA 800 x 600 56Hz VESA 800 x 600 60Hz VESA 800 x 600 75Hz VESA 800 x 600 72Hz MAC 832 x 624 75Hz...
  • Page 6 9.3.2 Fu n ction s Con trol is effected for th e pu sh -switch es to be u sed wh en th e u ser ch an g es th e parameters, in order to modify th e respecti v e settin g v alu e s. Wh eth er th e s witch h as been p ressed is iden ti fied with th e switch in pu t lev el th at is tu rn ed “...
  • Page 7 9.6 Power ON sequ en ce Wh en th e POWER switch is pressed, th e POWER OFF sig n al is tu rn ed “ H” . Wh en th is “ H” poten tial is detected, th e CPU beg in s to establish th e respectiv e power su pplies accordin g to th e sequ en ce sh own below. POWER PPWR D-SHCLK...
  • Page 8 9.7 Power OFF sequ en ce Wh en th e POWER switch is pressed wh ile th e power su pply is ON, th e POWER ON sig n al is tu rn ed “ H” . Wh en tsh own below.h is “ H” poten tial is detected, th e CPU beg in s to tu rn off th e respectiv e power su pplies accordin g to th e sequ en ce POWER PPWR...
  • Page 9 Inverter Th is u n it o perates on an ou tpu t v oltag e of 15V from po wer sou rce. 10.1 Reg u lato r: Q101 g e t a +5VDC for I102 power su pp ly . 10.2 UVP: Q106 tu rn s off wh en th e Vi n is u n der 14V.

  • Page 10: No Display Of Screen (Screen Is Black, Color Of Led Is Amber)

    1. No display of screen (Screen is black, color of LED is amber) Does OSD display when you push key button. 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.

  • Page 11: Nothing Displays On Screen (Screen Is Black, Color Of Led Is Green)

    2. Nothing displays on screen (Screen is black, color of LED is green) Is backlight lit? Does computer output RGB video signals? Check OSD menu is displayed on screen when you push the "PROCEED" key. Proceed "Abnormal screen" section. Page 2 Refer "Checking the backlight unit"...
  • Page 12 Continue Check the 3.3 V power are supplied on I308 pin 2. Is a dot clock being outputted under the condition that a LCD module is connected to P303 pin 44? Check the H-sync pulse of negative polarity is output on P303 pin 38 at TTL level. Check the V-sync of negative polarity are output on P303 pin 40.
  • Page 13 Continue Check the data enable of positive polarity are output on P303 pin 42. Check the data signal output on P306 and P303 R, G, B data pin. Failure point 1) The cable broke between P303 , P304 and LCD module. 2) LCD module failure.

  • Page 14: Checking The Back Light Unit

    3. Checking the back light unit Is +15V supplied to P803 pin 3, 4 to inverter PWB? Check the INV_EN signal of the rectangle input I307 pin 5 at TTL high level Check the PWM signal of the input from I303 pin 7 is a BRI signal Failure point 1) Inverter cable disconnection.

  • Page 15: Abnormal Screen

    4. Abnormal screen Check the R, G, B video signal from computer input on D-Sub R, G, B connector. Check the R, G, B input signals on I301 pin 12, 20, 28, respectively that their level is 0.7Vp-p maximum. Is the pulse of the TTL level being output to P303, P304 from the data line of I300? Check the negative horizontal sync pulse output to P304 pin 38 from I300 pin 80 at TTL level.

  • Page 16: No Osd Display

    5. NO OSD display Proceed "Checking the resolution change IC movement" section. Trou bl e Sh ooti ng Check the input of pulse from I300 pin 5, 6. 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.

  • Page 17: Abnormal Plug And Play Operation

    6. Abnormal plug and play operation 6.1 Abnormal DDC2 Confirm the input of serial data on I305 pin 6 synchronize SCLK at TTL level. 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.

  • Page 18: Checking The Interface Circuit Of Sync Signal

    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 Process "Checking the resolution change IC 7.2 Checking the control circuit of vertical sync pulse Check the vertical sync signal on I300 pin Process "Checking the resolution change IC Trou bl e Sh ooti ng pin 94 TTL level.

  • Page 19: Checking The Resolution Change Ic Movement

    8. Checking the resolution change IC movement Is there +3.3V supply on I300 pin 17, 21, 57, 77, 79, 97, 102, 117, 137, 154, 156, 157 and 65. Is 12MHz clock input to I300 pin 3 at TTL level? Is +5.0V supplied to I300 pin 2 at High level? Failure point I300 failure...

  • Page 20: No Power On

    9. No power on 9.1 No power on (I) Check power cord ( P801), Signal cable (P302),P802, P803, CN102, CN103 Check peak voltage of R811 triangle pulse is up to 1 volt or not. Check D809, D810, C816, C821, T802 have same short circuit, or the output Check feedback circuit around I802, I803 and the other components...
  • Page 21 9.2 No pow er on (II) Check the + 5V power is supplied Is LED turned on in amber momentarily when a power button is Proceed "Checking the operation of Page 12 from power source. Failure point Power source failure. pushed? Failure point Power source failure.

  • Page 22: Checking The Dc/Dc Converter Circuit

    A L C502 10. Checking the DC/DC converter circuit Check the output of 3.3V line voltage from I308 pin 2. Is the output FB321 being inputted to I308 pin 3? Failure point Printed wire broke between I308 pin 3 and output of FB322. Failure point I308 failure Failure point...

  • Page 23: Checking The Operation Of Cpu

    11. Checking the operation of CPU Is there +5.0V supply on I303 pin 44 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? Check the input of 5V "H" pulse from I310 pin 4 are same as I303 pin 10.

  • Page 24: Checking The Audio Circuit

    12. Checking the audio circuit OK NG host PC a minimum and off? Is correct output waveform being inputted from JK011 Is the waveform which is the inputted to I001 pin 4, 9? Is output wavefrom being outputted in I001 pin 14, 17? Failure point 1) Speaker cable disconnection 2) Speaker failure...

  • Page 25: Checking Inverter Board Circuit

    13. Checking inverter board circuit Check Vin pin is around 15.5V. On/off pin is over 2V. Brightness pin is between 0V and 3.7V. Check pin 5 of I102 is 5V. Check CN102, CN103 is connected right. Check pin 3 of I102 is over 2V. Check pin 18 of I102 is triangle pulse.

  • Page 26: Recommended Parts List

    1. Recommended Parts List Note: 1. The components identified by “ only the same parts specified. The components identified by “ * “ mark are critical parts. There is only OTP IC at the model beginning (FPR stage or before). When it put in mass production and there must be Mask coming out.

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