Macbook A1990 820-01041-A Dark Display

[Strolch]

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

[Strolch]

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]

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.

LCD pin top right 0.0072V
bottom right 3.369V
top left and bottom left 5.11V

[Strolch]

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

[mon2]

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.

[Strolch]

Re: Macbook A1990 820-01041-A Dark Display

Ok, pin 1to pin 46 or which pins should I measure? greeting

[mon2]

Re: Macbook A1990 820-01041-A Dark Display

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

See attached.

[Strolch]

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

[mon2]

Re: Macbook A1990 820-01041-A Dark Display

Voltage on pin #45 ?

Voltage on pin #46 ?

[Strolch]

Re: Macbook A1990 820-01041-A Dark Display

Pin 45 and Pin 46= 5.110V

[Strolch]

Re: Macbook A1990 820-01041-A Dark Display

Maybe U5210?

[mon2]

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

[Strolch]

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]

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]

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]

Re: Macbook A1990 820-01041-A Dark Display

I will look at the Backlight Flex Cable Connector of the A1989 A1990 A1706

[mon2]

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.

[Strolch]

Re: Macbook A1990 820-01041-A Dark Display

J8500 Pin 43?

[Strolch]

Re: Macbook A1990 820-01041-A Dark Display

I have from 8470-C8473=. 0,005V

[mon2]

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