[help] 820-01958 dead: 20v not switching

[phantomEVO]

ok and now?

[mon2]

Replace the connector.

[phantomEVO]

maybe you have not understood : like i said in post 55, i have already replaced the port, and now i have 5v@0,046 like at the beginning...with PPBUS_G3H 12,28
PP3V3_G3h loop from 2,52 to 2,66

[phantomEVO]

pp1v8_slp2r is 0v
pp3v3_g3h_rt is 3v
pp3v3_upc_t_ldo 3v
pp1v5_upc_t_ldo_core 1,5
pp3v3_upc_t_vout 0v
pp20v_usbc_t_vbus 5v
usbc_t_cc2 1,66
usbc_t_cc1 0v


BOTH PORTS

[mon2]

pp3v3_upc_t_vout 0v

Remove all power. Measure the resistance to ground of this LDO rail.

Suggest to also measure using DIODE mode. Red meter probe to ground. Black meter probe to this pin.

This is a LDO that should be present upon docking of the PD adapter. Either this rail is shorted or is defective and the CD321x controller needs to be changed. Interested in the diode mode measurement which will confirm if the BGA ball is soldered properly.

PS: Be careful of the posted net names. For example, there is a typo in PP1V8_SLPS2R which makes hunting for the same a time killer. As I tell my son, always double-check your work.

[phantomEVO]

0,560 in diode mode

[mon2]

This ldo rail should be working. To me, this controller is defective. This controller should be replaced.

[PITERPENY]

try to remove a pair of 3217 from any two-port board and be sure to mark them, you can't mix them up! just like you can't replace just one! very often the firmware of the CD just flies off.

[phantomEVO]

so the only way is to unsolder from donor board...(hoping they are fine)?

any 2 port board? not the same identical board?

[phantomEVO]

should i program again T2 SOC firmware chip like i did some post ago? or it is unuseful?

[mon2]

Attach the battery and check if you reach 20v on the power adapter.

[phantomEVO]

found a "semi-donor" board: i have changed u7000 and now ppbus_g3h is 12,31!

pp3v3_g3h still 2,5/2,6v!

with battery connected, i have 20v on both port @ 0,026! without battery, 5v

[mon2]

But is the voltage at the USB type C adapter @ 20V or 5V?

[phantomEVO]

what do you mean mon?...i've tried with original power supply, and power bench trough by-3200s: and i have 20v@0,026 on the usb meter as soon as i connect the cable

[mon2]

When you have 20v on the original Apple power supply, this confirms the PD controllers are working. By power on default, the external power adapters with power delivery all start at 5 volts. Only after some proper handshaking, the external power adapter will switch to 20v.

Once at 20v, the ISL regulator @ U7000 will enter buck mode. In buck mode, a higher input voltage will result in a lower output voltage. If the PD controller was not working, you will still have 12v3 to start on the board because the ISL regulator will be in boost mode where the low 5 volts input will be boosted to 12v3 for the initial setting.

Remain to use the original power supply and continue the debugging. The PD controllers must select 20v otherwise the PD controllers are still the suspects.

[phantomEVO]

ok i will continue to use original power supply, but know??? what to do???? problem seems now on 3v and 5v rail...i'm thinking of chaning u7650

[mon2]

Yes, U7650 is a cheap part that often fails (see Louis' videos). Replace it.

[phantomEVO]

no changes,,,

basic voltahe on u7650

pin 23, 22, 12, 13, 29, 21, 4.

12,31
0v
0
0v
0v
0v

[phantomEVO]

edit

[mon2]

Part is a known good part? Double-check the soldering. Flux and reflow the device. The LDOs on this part are also 0v? Check if they are shorted.