820-00850 stays at 5v

[2informaticos]

Use very tiny wire for this job.
0.01-0.02mm magnet wire can be found on Aliexpress.
You can also use broken iMac video cable to get fine wires too.

Consult schematic and boardview; some pads may not be needed.

 

[Blackmambo90]

Yes, some was not needed, but the wire i used, is it too big? Should i replace it? (I am not sure what is the size of this one

 

[2informaticos]

Not sure about the wire.
Just be sure remains sufficient space between balls and wire.
Also chip needs to seat correctly, to solder all the balls.

 

[Blackmambo90]

Okay tried to solder in a mew chip today - dame behavior as with no chip... wonder if its my soldering or if the chip is not the right one (order online)... any thoughts?

 

[2informaticos]

Can be solder problem, or fake chip (if chinese new)...

 

[Blackmambo90]

Long time long time...
After more than a year i finaly had some time to work on this one againe.

Ended up fixing most of the pads and installing another chip (ub300)
The mother board does boot and work now

How ever i have a couple questions:

1. I ended up not restoring 11, 22, and 26 (PP5V_S4_T_USBC) since they are all internaly related in the chip to pads 34 and 69 and those pads are still ok, also i have not fixed the pad 24 (UPC_TA_GPIO1) it look like it does not go anywhere
Is it critical?

2. I might damage the CB212 and C7006 in the procces. They look to be still connected but i am not sure. How crutial they are?

3. The usb ports on the side of the board where the ub300 is are not working, not sure if its related to the issue #4 there is power output but no data( ex mouse recive power but does not work)
But it does charge the mac itself if connected to charger with those ports

4. The mac does not wake up from the sleep. I am not yet sure why. Touchpad does click but black screen/no backlight. I run the diagnostic (D key) and there is no issues found


Pram reset did not help and it is freshly reinstalled os

Thank you!

 

[2informaticos]

"I ended up not restoring 11, 22, and 26 (PP5V_S4_T_USBC)"
That's not too good, but maybe not so critical.
There is the 5V power rail needed to power external USB device connected on the corresponding port.
Now only pin 34 is used and is no good idea to force that way.
Pin 69 has another function, even is connected in the same rail; not internally connected.

"i have not fixed the pad 24 (UPC_TA_GPIO1)"
Just a test point, not critical.

"I might damage the CB212 and C7006 in the procces."
None of them is critical.
Is better to remove them, if look like affected by corrosion.

"The mac does not wake up from the sleep."
I suspect Hall sensors issue (J4800/01); very likely affected by liquid.
Check U4802 voltages (lid open).

"The usb ports on the side of the board where the ub300 is are not working"
If USB mouse gets light, then 5V is delivered; that discard a problem related with mention #1.
There should be a communication problem.
Compare diode mode readings between J3300 and JB500; some data lines may be affected by corrosion.
Remove corresponding USB-C connector from shell and inspect its terminals.
the problem appears with both USB 2.0/3.0 devices?

 

[Blackmambo90]

Hello 2informaticos,
Thank you for answer

The board was not water damaged, the u300 was blown when the laptop fall down with hdmi connected

I have removed the hall sensor (j4800) while working on the u300 pads restoration.

The first boot after the u300 replacment was done with out j4800 installed. Mac was taking too long too boot, after that i reinstalled the hall sensor and the boot speed is okay now but maybe it was damaged by the temperature?
What should be the voltages of u4802?

"Compare diode mode readings between J3300 and JB500; some data lines may be affected by corrosion"
There is no water damage on the board but maybe the usb-c connector itself is bad (i am not sure if its good, i installed the one that was on my desk for months)

The mouse is usb2.0, i have not try usb3.0 (i see the power on the usbc to usba adapter)

 

[2informaticos]

Posibly broken traces when machine was dropped.
I recommend to inspect JB500 area and compare readings with J3300 side, for adjacent components.