820-02020

[Donlan78]

m1 MacBook Pro, with small issue, everything works except touchbar, the Touch Bar doesn’t power on after start up, but it will work if lid is closed and then opened there is no liquid damage and the Touchbar connectors look perfect,

 

[2informaticos]

Possibly AMR sensor issue.
The one connected to JR900 is first suspect.
Check UR200 signals behavior.

 

[Donlan78]

i a another 2020 m1 13" also no touch bar, this one had liquid damage, hard replace the connector JT700 pins 22,14,21 were in rough shape, had to run wire for pin 14, the others had enough pad to rebuild, anyhow i have 5v pin 22 and i have 1.8 pin 20,21, and 16 looks like i am missing 1.8v for reset L on pin 18, checked rt806 which is also 0v, but when the board is first powered on 1.8v is there for about 3 sec, is this normal, also any suggestions what else to check

 

[2informaticos]

Compare diode mode readings on touch bar connectors with good board.
Because of liquid, M1 might suffer damage through its lines connected to touchbar.

What about first machine?

 

[Donlan78]

checked diode mode reading, had short on the wire i ran, i replaced wire and retested, touch bar now powers lights up but no image just fine lines the entire touch bar.
first machine was set aside for now, hoping to figure out the liquid damaged board and then come back the the other I wasn't sure how to check arm sensors, there is no short on any of the pads, I ended up trying logic board with known good top case, then lost touch-bar completely figured best to set it aside for now

 

[2informaticos]

Test second board with known good touchbar.

 

[Donlan78]

same outcome with new top case, , lights up but distorted colors/lines, if i leave jt700(liquid damaged, replaced connector) disconnected but leave jt710 connected touch bar stays the same, lit up, but no image, distorted lines perhaps my issue is with JT710

 

[2informaticos]

That should be; JT700 is dedicated for touch functions only.

Check LT710/11 continuity.
Also compare diode mode readings on JT710 lines with good board.

 

[Donlan78]

Looks like jt710 has couple shorted pins, it’s clean but tested short, remive connector and pads were burned, intact but corroded and burned, was able to clean up pads. But don’t have a connector to put back on, any ideas where to buy, jt710 I have jt700 connectors but this one is unique

 

[Donlan78]

On the first board all diode readings are good on both connectors, but touchbar is dead, likely it’s going to be a bad resistor or cap somewhere, the circuit, or SDA issue, will
Look for missing. Components,

 

[2informaticos]

Look for it on previous T2 boards...

 

[Donlan78]

I pulled one from scrap a1706 board, will resume woring on it tomorow

 

[Donlan78]

ok, i pulled connector from a1706 board, it was a match, but i knocked off component on back side while reinstalling new connector, part that came off is ut710, is there another board i can pull this part from, i have tons on a2141, a2159,and a1990 board in scrap pile, i check pdf but not seeing it, hoping it has different part number for other boards

 

[2informaticos]

I'm afraid you can only find it in M1/2 boards.
However, with enough patience, you may use U8250 from A2159 for example.
You will need to place it upside down and solder with tiny wires...