820-01041-07 Stuck at 5.19V and 0.035A - PPBUS_G3H at 20mV - CHGR_EN_MVR unstable

[2informaticos]

Getting EN_MVR will not help you, until you get PPBUS_G3H; it powers 3V3_G3H_RTC power supply.

Post U7000 basic voltages, with charger alone (no battery); P_IN, AUX_DET, SMC_RST_IN, VDDA/P, CBC_ON, A/BMON.

 

[2informaticos]

You must get same behavior on all USB-C ports.
If not, you have problems on USB-C areas.

Check and compare diode mode readings around CD3215 chips.
Start with their LDOs and CC1/2 lines.

 

[stef4n]

Hi @2informaticos,

I did the measurements for U3100 and U3200, then when I saw the UB300 the cause of the issue became kind of obvious...

	U3100	U3200	UB300	UB400
	{} = XA	{} = XB	{}=TA	{}=TB
PP1V8_UPC_{}_LDOD	0.445V	0.445V	0.009V	0.446V
PP1V1_UPC_{}_LDO_BMC	0.451V	0.459V	0.45V	0.455V
PP3V3_UPC_{}_LDO	0.41V	0.406V	0.009V	0.41V
PP1V8_UPC_{}_LDOA	0.478V	0.48V	0.477V	0.48V
USBC_{}_CC1	0.535V	0.539V	0.5V	0.537V
USBC_{}_CC2	0.535V	0.54V	0.000V	0.473V

I missed it the first time I inspected the board; it was the single part of the Logic Board covered by a layer of dust.

 

[stef4n]

I removed the UB300, cleaned the pad and reapplied solder, but the pad 91 seems gone. I can't re-apply solder on it. What's the best way to fix that?

I assume I will have to solder a tiny wire from pin 2 of DB529 to pin 91 of the new CD3215.

But pin42 of JB500 seems a bit more problematic...It seems there is a trace from Pin 2 of DB529 to pin42 of JB500 though. So, would a wire from "pad 91" of UB300 to pin 2 of DB529 be enough ?

 

[2informaticos]

There are 3 more USB ports to use.
I don't think someone really needs to connect the charger and 3 USB devices at same time.
And probably that port will also work when you flip the USB device connected.

If you want to fix it properly, check trace continuity and see which part need to rebuild.

 

[stef4n]

I agree but ideally I'ld like to give back the device with 4 working USB-C port.
I blew away the ESD 8011 protection diodes DB504 and DB529

 

[stef4n]

I replaced the burnt CD3215. I did not put back theDB504 and DB529.

I now have 5.19V and 0.4A on 2 USB-C port (1 on each side of the board), the 2 other are still stuck at 0.034A

New measurements for U3100 and U3200

	U3100	U3200	UB300	UB400
	{} = XA	{} = XB	{}=TA	{}=TB
PP1V8_UPC_{}_LDOD	0.44V	0.453V	0.465V	0.455V
PP1V1_UPC_{}_LDO_BMC	0.458V	0.466V	0.72V	0.463V
PP3V3_UPC_{}_LDO	0.417V	0.414V	0.36V	0.417V
PP1V8_UPC_{}_LDOA	0.485V	0.487V	0.49V	0.488V
USBC_{}_CC1	0.54V	0.55V	0.54V	0.548V
USBC_{}_CC2	0.55V	0.55V	0.54V	0.548V

I checked 3 times PP1V1_UPC_TA_LDO_BMC on UB300, I got 0.72V each time, seems a bit high.
And LDO at 0.36V a little bit low

 

[2informaticos]

Did you solder same termination code?
C00, A12, B03 are not compatible.

Did you compare again diode mode readings around the CD3215 chips?
Do you get correct LDOs voltage on all of them?

 

[stef4n]

Did you solder same termination code?
C00, A12, B03 are not compatible.

Did you compare again diode mode readings around the CD3215 chips?
Do you get correct LDOs voltage on all of them?

Yes sir I did, CD3215C00Z,
Yes I did took new measurements around the CD3215, I was editing my post to include these measurement when you replied

LDO reading seems a bit high for PP1V1_UPC_{}_LDO_BMC and a bit low for PP3V3_UPC_{}_LDO

 

[2informaticos]

I don't like the reading at 1V1_LDO_BMC.
Did you let the board cool down before measure it?

 

[stef4n]

Yesterday evening, probably yes as I cleaned everything for a few minutes. Tonight, the measurement is the same: 0.72V

 

[2informaticos]

Then you have bad solders, or that chips is bad.

Please, don't quote an entire post, visible few centimeters above...

 

[stef4n]

Sorry for the quote, i must have missclicked.
WIll redo the job this evening and let you know. Thanks.

Edit: CB304 is now out of the board,it looks like I perhaps broke it while trying to measure 1V1_LDO_BMC. Can't solder it back in place.
I measured it, 1.12uF. If I can measure it, I don't understand why I can't put it back in place.

Edit: I found a 820-1958 (MAcBook Air 2020) donor board, took the C2830, schematics shows 2.2uF, measured it, 0.3nF...going to pick them all one by one and test as I do not have any 2018 MacBook Pro donor board
Might be luckier if I pick one on the same part of the circuitry xD

Edit: C3206, 1.03uF, but 6.3V; C4423, 2.1uF, 4V
Looks like I ripped off the pad of CB304, will scratch the surface to solder on the trace

I replaced the CD3215;

	UB300
	{}=TA
PP1V8_UPC_{}_LDOD	0.44V
PP1V1_UPC_{}_LDO_BMC	0.455V
PP3V3_UPC_{}_LDO	0.355V
PP1V8_UPC_{}_LDOA	0.478V
USBC_{}_CC1	0.542V
USBC_{}_CC2	0.543V

1V1_UPC_TA_LDO_BMC is now in line. But, I still have to solder back a new CB304

I didn't succeed, but I plugged the power, and I still get 5.19V@0.03A on 1 port on each side, and 5V@0.36A on the other. That's less than before actually.