(347) 552-2258 help@rossmanngroup.com

A1989 - One USB-C port doesn't work.

M

Mattpd

Member
Sorry, I don't know where the board number is on this one... Complaint was USB port problems and high fan speed. I have yet to hear the fans spin fast though.

Water damaged. Someone has attempted to clean the board so corrosion is hard to find, but it's obvious water did hit near one of the CD3215 ICs.

Three of the four USB-C ports work fine, and will charge the machine with 20v and 2A.

However the port in the back left does not work properly. If I plug tester in one direction I get 5v and 0A, and if I flip the connection over the tester fails to even power on.

Everything I have read says if one CD3515 is bad, all USB ports will stop functioning. If this is accurate information, does it rule out CD3215 problem here?
 
2informaticos

2informaticos

Administrator
Staff member
Depends of CD3215 failure type.
Seems that you have problems on CC1/2 lines of that port.
Compare diode mode readings with the other CD3215 chips.
 
M

Mattpd

Member
It looks like all four CD3215 have the same diode mode reading for "USBC_XA_CC1" and "USBC_XA_CC2"

Around 0.588

Are there any other lines that need to be compared?
 
M

Mattpd

Member
Here are the results. All four chips have the same diode mode measurement for the LDO rails.

All voltages are present. It seems PP1v1_UPC_XB_LDO_BMC only comes up on the chip that the USB cable is plugged into.

If I move the cable to all four ports, I can find this voltage only on three of them.

When I plug into the "bad" port I can not find this voltage on U3200, which is where most of the liquid hit.

U3200 -

2) PP1v8_UPC_XB_LDOD - 0.482 / 1.8v
35) PP1v1_UPC_XB_LDO_BMC - 0.513 / 0.0v <----
53) PP3v3_UPC_XB_LDO - 0.505 / 3.3v
75) PP1v8_UPC_XB_LDOA - 0.521 / 1.8v

UB400 -

2) PP1v8_UPC_XB_LDOD - 0.485 / 1.8v
35) PP1v1_UPC_XB_LDO_BMC - 0.514 / 1.1v
53) PP3v3_UPC_XB_LDO - 0.506 / 3.3v
75) PP1v8_UPC_XB_LDOA - 0.522 / 1.8v

U3100 -

2) PP1v8_UPC_XB_LDOD - 0.489 / 1.8v
35) PP1v1_UPC_XB_LDO_BMC - 0.518 / 1.1v
53) PP3v3_UPC_XB_LDO - 0.503 / 3.33v
75) PP1v8_UPC_XB_LDOA - 0.528 / 1.8v

UB300 -

2) PP1v8_UPC_XB_LDOD - 0.489 / 1.8v
35) PP1v1_UPC_XB_LDO_BMC - 0.518 / 1.1v
53) PP3v3_UPC_XB_LDO - 0.504 / 3.3v
75) PP1v8_UPC_XB_LDOA - 0.526 / 1.8v
 
Last edited:
M

Mattpd

Member
I reflowed it and it seems to have fixed the bad USB port.

I wanted to test the machine with my USB test disk, but I can't get the boot menu to appear by holding the "options" button. Immediately when the machine turns on the Apple logo appears and it boots customers SSD.

Tried PRAM reset but it doesn't seem to work. Maybe I should be treating this differently than old models? Or is there still something broken?
 
You must log in or register to reply here.
Top