Badcaps.net Forum
Go Back   Badcaps Forums > Troubleshooting Hardware & Devices and Electronics Theory > Troubleshooting Laptops, Tablets, and Mobile Devices
Register FAQ Calendar Search Today's Posts Mark Forums Read

 
Thread Tools Display Modes
Old 10-31-2022, 04:17 PM   #1
Strolch
Senior Member
 
Join Date: Nov 2017
City & State: Aurich Niedersachsen
My Country: Deutschland
Line Voltage: 230V 50Hz
I'm a: Knowledge Seeker
Posts: 169
Default Macbook A1990 820-01041-A Dark Display

Hello, I have a MacBook Pro 15 inch 2018. A1990 Board 820-01041-A. The MacBook has water damage. It works but the display stays black. I took a picture of the LVDS connector. there you can see on the thick pin over IPX that there was a short circuit. there is also zero volts. Have any of you had the same problem? Thanks
Attached Images
File Type: jpg A1990 820-01041-A.jpg (410.0 KB, 35 views)
File Type: jpg A1990 01041-A.jpg (432.3 KB, 31 views)
Strolch is offline   Reply With Quote
Old 11-06-2022, 11:07 AM   #2
Strolch
Senior Member
 
Join Date: Nov 2017
City & State: Aurich Niedersachsen
My Country: Deutschland
Line Voltage: 230V 50Hz
I'm a: Knowledge Seeker
Posts: 169
Default Re: Macbook A1990 820-01041-A Dark Display

Hello, I have now made a few more measurements on the board with the power supply connected.
Strolch is offline   Reply With Quote
Old 11-06-2022, 11:10 AM   #3
Strolch
Senior Member
 
Join Date: Nov 2017
City & State: Aurich Niedersachsen
My Country: Deutschland
Line Voltage: 230V 50Hz
I'm a: Knowledge Seeker
Posts: 169
Default Re: Macbook A1990 820-01041-A Dark Display

Quote:
Originally Posted by Strolch View Post
Hello, I have now made a few more measurements on the board with the power supply connected.
LCD pin top right 0.0072V
bottom right 3.369V
top left and bottom left 5.11V
Attached Images
File Type: jpg 20221106_174534.jpg (355.8 KB, 15 views)
File Type: jpg 20221106_174637.jpg (258.5 KB, 13 views)
File Type: jpg 20221106_174556.jpg (430.1 KB, 11 views)
Strolch is offline   Reply With Quote
Old 11-06-2022, 11:13 AM   #4
Strolch
Senior Member
 
Join Date: Nov 2017
City & State: Aurich Niedersachsen
My Country: Deutschland
Line Voltage: 230V 50Hz
I'm a: Knowledge Seeker
Posts: 169
Default Re: Macbook A1990 820-01041-A Dark Display

on the second picture I measured 0.004V for the 5 in the row and 0.0035V for picture 3 and 12.55V for the fuse
Strolch is offline   Reply With Quote
Old 11-06-2022, 11:26 AM   #5
mon2
Badcaps Veteran
 
mon2's Avatar
 
Join Date: Dec 2019
City & State: Windsor, Ontario
My Country: Canada
Line Voltage: 110VAC
I'm a: Knowledge Seeker
Posts: 5,445
Default Re: Macbook A1990 820-01041-A Dark Display

Hi. Best to use pin numbers from the BV file for this logic board.

Can you measure and post your voltage readings of J8500?

In the meantime, need to collect the 10,000 leaves in the backyard - it is a favorite past time. Want to burn them along with the audio equipment used by the neighbors for their outdoor karoake sessions.
Attached Images
File Type: png j8500.png (84.4 KB, 8 views)
mon2 is offline   Reply With Quote
Old 11-06-2022, 11:51 AM   #6
Strolch
Senior Member
 
Join Date: Nov 2017
City & State: Aurich Niedersachsen
My Country: Deutschland
Line Voltage: 230V 50Hz
I'm a: Knowledge Seeker
Posts: 169
Default Re: Macbook A1990 820-01041-A Dark Display

Ok, pin 1to pin 46 or which pins should I measure? greeting
Strolch is offline   Reply With Quote
Old 11-06-2022, 12:48 PM   #7
mon2
Badcaps Veteran
 
mon2's Avatar
 
Join Date: Dec 2019
City & State: Windsor, Ontario
My Country: Canada
Line Voltage: 110VAC
I'm a: Knowledge Seeker
Posts: 5,445
Default Re: Macbook A1990 820-01041-A Dark Display

Start with the voltage to ground check of each of the I2C pins.

See attached.
Attached Images
File Type: png J8500_I2C_lines.png (208.2 KB, 10 views)
mon2 is offline   Reply With Quote
Old 11-07-2022, 12:06 PM   #8
Strolch
Senior Member
 
Join Date: Nov 2017
City & State: Aurich Niedersachsen
My Country: Deutschland
Line Voltage: 230V 50Hz
I'm a: Knowledge Seeker
Posts: 169
Default Re: Macbook A1990 820-01041-A Dark Display

Hi,
i have
Pin 24=5.108V
Pin 26=5.104V
Pin 28=3.36V
Pin 30=3.36V
Pin 32=0.0004V
Pin 34-40 All= 1.7934V
Strolch is offline   Reply With Quote
Old 11-07-2022, 01:01 PM   #9
mon2
Badcaps Veteran
 
mon2's Avatar
 
Join Date: Dec 2019
City & State: Windsor, Ontario
My Country: Canada
Line Voltage: 110VAC
I'm a: Knowledge Seeker
Posts: 5,445
Default Re: Macbook A1990 820-01041-A Dark Display

Voltage on pin #45 ?

Voltage on pin #46 ?
mon2 is offline   Reply With Quote
Old 11-07-2022, 02:37 PM   #10
Strolch
Senior Member
 
Join Date: Nov 2017
City & State: Aurich Niedersachsen
My Country: Deutschland
Line Voltage: 230V 50Hz
I'm a: Knowledge Seeker
Posts: 169
Default Re: Macbook A1990 820-01041-A Dark Display

Pin 45 and Pin 46= 5.110V
Strolch is offline   Reply With Quote
Old 11-08-2022, 07:21 AM   #11
Strolch
Senior Member
 
Join Date: Nov 2017
City & State: Aurich Niedersachsen
My Country: Deutschland
Line Voltage: 230V 50Hz
I'm a: Knowledge Seeker
Posts: 169
Default Re: Macbook A1990 820-01041-A Dark Display

Maybe U5210?
Strolch is offline   Reply With Quote
Old 11-09-2022, 04:59 PM   #12
mon2
Badcaps Veteran
 
mon2's Avatar
 
Join Date: Dec 2019
City & State: Windsor, Ontario
My Country: Canada
Line Voltage: 110VAC
I'm a: Knowledge Seeker
Posts: 5,445
Default Re: Macbook A1990 820-01041-A Dark Display

Fault may be that U9850 is damaged (MUX).

See 'NO IMAGE' here:

https://repair.wiki/w/A1990_2018-201...ar_MacBook_Pro

If you suspect U5210 - measure the voltage of the I2C lines on both sides of U5210.

That is,

I2C_DISP_SCL
I2C_DISP_SDA

I2C_TCON_SCL
I2C_TCON_SDA
mon2 is offline   Reply With Quote
Old 11-11-2022, 07:44 AM   #13
Strolch
Senior Member
 
Join Date: Nov 2017
City & State: Aurich Niedersachsen
My Country: Deutschland
Line Voltage: 230V 50Hz
I'm a: Knowledge Seeker
Posts: 169
Default Re: Macbook A1990 820-01041-A Dark Display

Hi,
The link doesn't work.
https://repair.wiki/w/A1990_2018-201...ar_MacBook_Pro
Strolch is offline   Reply With Quote
Old 11-11-2022, 07:48 AM   #14
Strolch
Senior Member
 
Join Date: Nov 2017
City & State: Aurich Niedersachsen
My Country: Deutschland
Line Voltage: 230V 50Hz
I'm a: Knowledge Seeker
Posts: 169
Default Re: Macbook A1990 820-01041-A Dark Display

But I have already exchanged the chip on an A1707 and then it was fine again! I will try it. br
Strolch is offline   Reply With Quote
Old 11-24-2022, 12:11 PM   #15
Strolch
Senior Member
 
Join Date: Nov 2017
City & State: Aurich Niedersachsen
My Country: Deutschland
Line Voltage: 230V 50Hz
I'm a: Knowledge Seeker
Posts: 169
Default Re: Macbook A1990 820-01041-A Dark Display

Hi mon2,

I swapped the U9850. The display is getting power now but I don't have a backlight. greeting
Strolch is offline   Reply With Quote
Old 11-24-2022, 12:16 PM   #16
Strolch
Senior Member
 
Join Date: Nov 2017
City & State: Aurich Niedersachsen
My Country: Deutschland
Line Voltage: 230V 50Hz
I'm a: Knowledge Seeker
Posts: 169
Default Re: Macbook A1990 820-01041-A Dark Display

I will look at the Backlight Flex Cable Connector of the A1989 A1990 A1706
Strolch is offline   Reply With Quote
Old 11-24-2022, 01:22 PM   #17
mon2
Badcaps Veteran
 
mon2's Avatar
 
Join Date: Dec 2019
City & State: Windsor, Ontario
My Country: Canada
Line Voltage: 110VAC
I'm a: Knowledge Seeker
Posts: 5,445
Default Re: Macbook A1990 820-01041-A Dark Display

Very good - do check the backlight voltage at the logic board to see if it is being created.
mon2 is offline   Reply With Quote
Old 11-24-2022, 01:34 PM   #18
Strolch
Senior Member
 
Join Date: Nov 2017
City & State: Aurich Niedersachsen
My Country: Deutschland
Line Voltage: 230V 50Hz
I'm a: Knowledge Seeker
Posts: 169
Default Re: Macbook A1990 820-01041-A Dark Display

J8500 Pin 43?
Strolch is offline   Reply With Quote
Old 11-24-2022, 02:28 PM   #19
Strolch
Senior Member
 
Join Date: Nov 2017
City & State: Aurich Niedersachsen
My Country: Deutschland
Line Voltage: 230V 50Hz
I'm a: Knowledge Seeker
Posts: 169
Default Re: Macbook A1990 820-01041-A Dark Display

I have from 8470-C8473=. 0,005V
Strolch is offline   Reply With Quote
Old 11-24-2022, 04:50 PM   #20
mon2
Badcaps Veteran
 
mon2's Avatar
 
Join Date: Dec 2019
City & State: Windsor, Ontario
My Country: Canada
Line Voltage: 110VAC
I'm a: Knowledge Seeker
Posts: 5,445
Default Re: Macbook A1990 820-01041-A Dark Display

Measure the voltage to ground for the following points of interest:

EDP_BKLT_EN

PPVIN_S0SW_LCDBKLT_R

LCDBKLT_EN_L

PPVIN_S0SW_LCDBKLT
Attached Images
File Type: jpg backlight.jpg (398.3 KB, 13 views)
mon2 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



Badcaps.net Technical Forums 2003 - 2022
Powered by vBulletin ®
Copyright ©2000 - 2022, Jelsoft Enterprises Ltd.
All times are GMT -6. The time now is 05:03 PM.
Did you find this forum helpful?