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820-02098 one port stuck on 5v

T

tcampbell34

Member
I have a 820-02098 that had liquid damage on the UG400 side of the board. Liquid damage was moderate. I cleaned the liquid damage and replaced a bunch of corroded caps and resistors. I get 20v and the board turns on and boots to the OS when using any of the ports on the left side of the mac, but the port on the right side for UG400 only gives me 5v 20ma. I checked diode mode values on all the resistors and caps around UG400 and they all seem to match with a good board. Not sure where to look next.

With charger connected to UG400:

PPVBUS_USBC2 - 5v
PP3V3_UPC_LDO - 3.4v
PP1V5_UPC2_LDO_CORE - 1.5v
PPBUS_AON - 0.748v
PPDCIN_AON - 0v
PP3V8_AON - 0v
 
T

tcampbell34

Member
Also changed UG000, no change. Checked diode mode values on JG600 and they all match with JF600/601. It seems this CD3217 is not communicating with the ISL or M1 to generate PPDCIN voltage
 
2informaticos

2informaticos

Administrator
Staff member
Maybe not a good chip, or bad solders.

Just for test, connect a diode with A on PPVBUS_USBC2 and K on FG200.
Use 5A (or more) Schottky diode.
 
2informaticos

2informaticos

Administrator
Staff member
You can try, at least to see if that port switch to 20V.

I've done diode trick on few old A1708, where one port didn't want to work in normal mode.
The diode is needed to protect an external USB device (not charger), connected on that port.
 
T

tcampbell34

Member
Ok I tried that and now I get 5v 260ma for the first few seconds and then it drops to 5v 50ma. PPVBUS_USBC2 is 5.12v but PPDCIN_AON is only 4.76v. PPBUS is now 12.01v.
 
T

tcampbell34

Member
It was UF980. With the charger connected, I was getting like 2.5v on USBC2_CC1_CONN but 0v on USBC2_CC1. Replaced UF980 with a chip from a donor board and now this port gives me 20v and works correctly.
 
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