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Old 04-19-2020, 05:12 PM   #1
Roli
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Default Acer 8943g shorted motherboard with LVDS connector

Hello , so i forgot that my laptop had a battery in it ... and plugged in the lvds connector to the display, yes i know stupid , and then i smelled something burning , so when i started up the laptop i had a white screen , and after that not even a white screen anymore , it is black , no backlight and also no image , the vga port works fine , the laptop boots .
I tried with a flashlight to see if there is image ,but no image.

There was a small smd on the motherboard marked as : L43 , it was burned i changed it , but i still dont have any image , only on vga.

And no the motherboard has no fuses near the Lvds, so maybe someone has a better ideea ?

I have some images of the board and what i changed .
Thankyou !
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File Type: jpg 20200420_013943.jpg (721.7 KB, 33 views)
File Type: jpg 20200420_013858.jpg (1,001.7 KB, 25 views)
File Type: jpg 20200420_013908.jpg (981.5 KB, 25 views)
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Old 04-20-2020, 04:42 AM   #2
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Default Re: Acer 8943g shorted motherboard with LVDS connector

Nobody any ideea ?
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Old 04-21-2020, 05:19 AM   #3
lapfix
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Default Re: Acer 8943g shorted motherboard with LVDS connector

Make sure that your problem is NOT on LVDS cable or LED panel.change them and see if your issue is gone
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Old 04-21-2020, 04:54 PM   #4
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Default Re: Acer 8943g shorted motherboard with LVDS connector

Quote:
Originally Posted by lapfix View Post
Make sure that your problem is NOT on LVDS cable or LED panel.change them and see if your issue is gone
Thanks for replying , ive checked the lvds , its okay, but i managed to find an acer 15.6 inch display with same 40 pin connector and gues what , the display turned on perfectly , so now i know the motherboard is okay , lvds ok , all compoennts okay ,except the display

The display board failed on the display , but again i dont see anything burnd or suspicious , so i think there is a short somewhere and cuts off the whole display , so it wont turn on , i see some test points on the displays board :

LED_PWM
LED_EN
EE_VDD
SC
SD
GND1
N-WE

Maybe someone repaird laptop display boards and can lead me further ?
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Old 04-21-2020, 05:28 PM   #5
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Default Re: Acer 8943g shorted motherboard with LVDS connector

Ok so after a better examination i have found the problem ( posible problem ) , found a burned resistor , but the problem is i cannot see the value of it , i cannot read the middle of what it says on the resistor , only the left and right side but not the middle , ive made a picture .

It writes E E , left and right side , but cannot determin on middle , now what should i do ?
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Old 04-21-2020, 11:59 PM   #6
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Default Re: Acer 8943g shorted motherboard with LVDS connector

Look where the resistor is connected to. Zoomed out picture might be helpful. The planes that the resistor is connected to seem big, also there is a conductive tape on one of the planes, usually these are put on GND planes.
Might be 3R3 resistor acting as current limiter.
Not sure - so do not act on this suggestion.
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Old 04-22-2020, 02:19 AM   #7
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Default Re: Acer 8943g shorted motherboard with LVDS connector

Perfect , you can easy guess the resistor value , any 15.6 inch display / 40 pin connector can give you an idea .
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Old 04-22-2020, 09:02 AM   #8
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Default Re: Acer 8943g shorted motherboard with LVDS connector

Ok i managed to change the resistor , the display still wont start , ive managed check an IC marked as : S24C02 , its a 2Wire serial eeprom , donno why but its verry hot , and its shorted to ground ...
I think i am going to remove that and check if it works maybe without , but i dont think so ...
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Old 04-22-2020, 09:24 AM   #9
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Default Re: Acer 8943g shorted motherboard with LVDS connector

The S24C02 is the EDID eeprom. You`ll need to program a new chip. What part number is the panel ,post a picture.
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Old 04-22-2020, 05:34 PM   #10
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Default Re: Acer 8943g shorted motherboard with LVDS connector

The model number is N184H6 - L02 Rev.C1 , posted picture .
So basically i need to order a new chip and reprogram - it ?
If yes i have only 1 programmer , TL866 , need to check if it supports this chip ...
Or are there any other ways to program this ? Maybe using paralel port or serial port ?
And where can i get firmware for this ?
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Old 04-23-2020, 03:35 AM   #11
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Default Re: Acer 8943g shorted motherboard with LVDS connector

I posted the bin in the LCD EDID dump thread, post #42 . https://www.badcaps.net/forum/showthread.php?p=957055
If you don`t have an adapter for the tl866 you could use an old lvds cable to flash it (post #6). Any 24C02 chip will do from an old panel, RAM ,HDD,scrap pcb .
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Old 04-23-2020, 04:41 AM   #12
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Default Re: Acer 8943g shorted motherboard with LVDS connector

Wow thanks for the quick reply , i will try to find a good chip , hopefully today !
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Old 04-23-2020, 12:53 PM   #13
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Default Re: Acer 8943g shorted motherboard with LVDS connector

Quote:
Originally Posted by SMDFlea View Post
I posted the bin in the LCD EDID dump thread, post #42 . https://www.badcaps.net/forum/showthread.php?p=957055
If you don`t have an adapter for the tl866 you could use an old lvds cable to flash it (post #6). Any 24C02 chip will do from an old panel, RAM ,HDD,scrap pcb .
Ok so i managed to program the new ic with the file you provided, the display turns on but its only white .
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File Type: jpg 20200423_205256.jpg (651.4 KB, 14 views)
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Old 04-23-2020, 12:55 PM   #14
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Default Re: Acer 8943g shorted motherboard with LVDS connector

Ok what i found just now that there is another ic that is getting verry verry hot , the writing on the ic is : CW=BJ 12R , i cannot find anything about this ic , what is this and where can i get one ?
Posted picture of the ic .
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Old 04-23-2020, 01:23 PM   #15
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Default Re: Acer 8943g shorted motherboard with LVDS connector

Its a Richtek RT9921CGQV .https://www.richtek.com/assets/produ.../DS9921-04.pdf
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Old 04-23-2020, 03:57 PM   #16
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Default Re: Acer 8943g shorted motherboard with LVDS connector

I found a similar chip , posted picture , is that the same thing is it okay to change it ?
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Old 04-23-2020, 05:55 PM   #17
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Default Re: Acer 8943g shorted motherboard with LVDS connector

Nevermind that is an LED driver i think ...
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Old 04-23-2020, 06:02 PM   #18
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Default Re: Acer 8943g shorted motherboard with LVDS connector

Quote:
Originally Posted by SMDFlea View Post
I will have to order it from china , it will take like 2 months because i dont have one , on this N184H6 display , there is another ic , it is not hot or anything , but im afraid if i order the RT9921 and change it , maybe this other ic will be hot to and i want to order that also because i dont want surprises , so on the other ic it writes DW=BK W16 , what ic is this ?

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Old 04-24-2020, 04:11 AM   #19
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Default Re: Acer 8943g shorted motherboard with LVDS connector

It could be a Richtek RT8562BGQW DW=xx

https://www.ebay.com/itm/3pcs-RT8562...-/401680959547

EDIT: Datasheet https://www.richtek.com/assets/produ...DS8562B-06.pdf

Last edited by SMDFlea; 04-24-2020 at 08:35 AM..
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Old 04-24-2020, 08:29 AM   #20
Roli
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Default Re: Acer 8943g shorted motherboard with LVDS connector

Quote:
Originally Posted by SMDFlea View Post
It could be a Richtek RT8562BGQW DW=xx

https://www.ebay.com/itm/3pcs-RT8562...-/401680959547
You have been verry helpfull , thankyou ! , and about that 2 ic-s that i need , are those available only in display's or can you find them maybe on laptop motherboards or something ?
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