820-00923 shorting out CD3215 chip

Soji

Member
Board came in dead and was drawing 5V, discovered U3100 and UB400 were very hot, and there was corrosion on C7000, C7001 and CB214, and they were all replaced. The type-c ammeter was connected to the board and it draws 20V for about 5secs and the type-c ammeter went off, unplugged it and plugged it back, it draws only 5V again, and discovered U3100 was very hot again and there was a short on (PP3V3_UPC_XA_LDO), when the U3100 IC was removed the short disappeared, replaced it again, board draws 20V again, the computer was assembled and powered on, it worked pretty well for about 20mins, and it went off, unplugged the ammeter and plugging it back, we tested it with all ports it draws 5V again, and discovered U3100, U3200 and UB300 is getting hot again, 50 degrees C, according to the thermal camera used.
 

2informaticos

Administrator
Staff member
Are you working with original Apple 87/96W charger?
Check Q3100/200 and QB300/400 for internal short.

Once get the board working, check L3500 and LB700 voltages; remember to connect an USB device to enable them.
 

Soji

Member
u3100,u3200 and UB300 were shorted on (PP3V3_UPC__LDO) , i removed them, short gone, i now checked Q3100/200 and QB300/400 for internal short , no internal short. installed another set of cd3215, i got 20v on typec ammeter. the pc is charging and its working , so
i got 5v on L3500,5v on LB700 respectively after inserting a usb flash drive, but one out of the 4 ports is not working both sides
 

2informaticos

Administrator
Staff member
Which port doesn't work properly?
Check and compare diode mode on its CC1/2 lines.
Also remove USB-C connector from the case and check its contacts.
 

Soji

Member
the first port by the right when screen laptop facing me or rather next port after the audio jack port.
there is a short on USBC_TA_CC2
 

Soji

Member
i replaced UB300..short gone USBC_TA_CC2,all the ports are working perfectly well, shortly after that
u3200 got shorted again on PP3V3_UPC_XB_LDO
 
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