820-3437 not connecting device.

Yoel Ren

Member
this machine come in dead. theres something to do with all sys pwrgd not showing, so I remove q8150. now machine turn on.
a few weeks later customer say macbook cannot connect to device. i use my known good cable to my device, its charging but itunes doesnt detect device.
I have discard all part problem, and use my own ssd with big sur. but still doesnt see device. mouse and usb drive works fine at both usb port. any advice ?
 

Yoel Ren

Member
the device will show and disconnected, show and disconnected, in the finder. the charging indicator on the device stay charging.
both port behave the same, so im sure this is not a usb port solder joint connection problem
 

2informaticos

Administrator
Staff member
Looks like you have problems with USB 3.0 connection.
Check corresponding protection diodes and series caps.
 

Yoel Ren

Member
do you mean the usb3_exta and extb line ?

all diode and caps is good and doesnt have continuity to its other end.
 

2informaticos

Administrator
Staff member
Compare diode mode readings to ground with good board, on all 4 lines.
Also check the value on both sides of the series caps.
 

Yoel Ren

Member
i diode mode all that line.
USB3_EXTA_D2R_N
USB3_EXTA_D2R_P
USB3_EXTA_R2D_C_N
USB3_EXTA_R2D_C_P
USB3_EXTA_R2D_N
USB3_EXTA_R2D_P
and the extb one too.

no diode is shorted, the caps all have 0.310 at one side, and O.L at the other side, all good.
is this pch problem?
 

Yoel Ren

Member
both L1290 and L1295 have 1.05v at both side of the component. I dont see any related usb 3 thing to check anymore.
can I assume this is pch no fix ?
 
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