820-01521-02 - not powering on [SOLVED]

[nameless]

Hey everybody, I've got A1932 EMC 3184 which doesn't turn on anymore

HISTORY : customer said that in the beginning on of the usb-c port stopped charging, then a week later another. So none of the ports are working.

MEASUREMENTS :

The mb pulls 5.24V - 0.15A on port closest to the screen
And 5.20V - 0.357A on port closest to the trackpad ))

PPBUS_G3H - on C6481 - 12.32V
R7020 - 5.15V
U6940 - pin1 = 3.28V, pin10 = 0V on R6941/40

Is the U6940 (SLG4AP41183) dead ?

If I understood correct from the other thread it should have some voltage on pin 10 too

Thanks for your support

Regards

 

[2informaticos]

The big difference of current consumption between the USB-C ports, points to a problem on that area.
Post voltage and diode mode to ground at LDO outputs of both CD3215.

"If I understood correct from the other thread it should have some voltage on pin 10 too"
Only if pins 3 & 4 are controlled correctly.

 

[nameless]

thanks for your reply

U3100
PP1V8_UPC_XA_LDOD - 1.8V / diode mode 0.47
PP1V1_UPC_XA_LDO_BMC - 0.03V / 0.50
PP3V3_UPC_XA_LDO - 3.3V / 0.48
PP1V8_UPC_XA_LDOA - 1.8V / 0.51

U3200
PP1V8_UPC_XB_LDOD - 2.1V / 0.38
PP1V1_UPC_XB_LDO_BMC - 0.03V / 0.50
PP3V3_UPC_XB_LDO - 3.3V / 0.37
PP1V8_UPC_XB_LDOA - 1.8V / 0.51

U6940 - pin3 - 3.28V, pin4 - 3.28V

Also I'm getting U3200 warming up very quickly, no matter which port i plugin

 

[2informaticos]

"PP1V8_UPC_XB_LDOD - 2.1V / 0.38"
Change U3100.

U6940 looks good...

 

[nameless]

will do ))

I've got 820-00244 donor board it has u3100 CD3215B01 do you think it can fit ?

From schematics look like the same

 

[2informaticos]

Termination code is VERY important!!!

 

[nameless]

loool

PP1V1_UPC_XB_LDO_BMC - is U3200 (my bad)

spent an hour reballing a foking wrong chip )) hahaha

Placed CD3215B01 from donor and was getting 20V on one of the ports, the other one stuck at 5V

Completely removed U3100 (donor chip) and back to 5V 0.2A

Indeed is not the same code - needed part is CD3215C00

 

[2informaticos]

"Completely removed U3100 (donor chip) and back to 5V 0.2A"
Both chips MUST be present on the board.

CD3215C00 can't be replaced with CD3215B01; internal firmware is different.

 

[nameless]

Ok just received and installed a new CD3215C00 getting same reading as with CD3215B01

One port takes 20V the other one 5V, should both ports pulling 20V ?

On u3200 now the readings are correct

PP1V8_UPC_XB_LDOD - 1.8V / 0.48

 

[2informaticos]

Both ports must have same behaviour.
Check the 4 connections possible also.

 

[nameless]

U3100
PP1V8_UPC_XA_LDOD - 1.8V / diode mode 0.47
PP1V1_UPC_XA_LDO_BMC - 0.00V / 0.50
PP3V3_UPC_XA_LDO - 3.3V / 0.49
PP1V8_UPC_XA_LDOA - 1.8V / 0.51

U3200
PP1V8_UPC_XB_LDOD - 1.8V / 0.48
PP1V1_UPC_XB_LDO_BMC - 0.00V / 0.51
PP3V3_UPC_XB_LDO - 3.3V / 0.50
PP1V8_UPC_XB_LDOA - 1.8V / 0.52

hmm

could this be the flex it-self ?

bmc went to 0V

 

[2informaticos]

1V1 LDO (BMC voltage) is generated by CD3215, when powered.
Check for knocked off, or moved components; also broken traces.
Be sure to solder correctly the CD3215 chips.

 

[nameless]

hmmm how is that even possible

ok i did all that 3 times(no exaggeration) with exact same results (so we can exclude bad soldering)

when original placed on U3200 and connected to upper port i'm getting correct voltages on all LDOs and getting 20V on that port

when the replaced is on U3100 i'm missing BMC 1V1 - all others LDOs are good and getting 5V / 0.27A

when original is placed on U3100 i'm missing BMC 1V1 - all others LDOs are good and getting 5V /0.27A

and when replaced is on U3200 i'm missing BMC 1V1 - all others LDOs are good and getting 5V/0.27A

is the replaced one is faulty ? If so why don't I get 1v1 when the original is on U3100 ?

ordered another two CD3215 will receive em soon

also tried with another dc dock

 

[2informaticos]

1V1 LDO must appear only on the powered port.
So, when you check it, connect the charger accordingly.

If you get 20V with original chip in place of U3200, at least you know that chip is good.
If the same port stays at 5V with any other chip, then none of them is good; considering all soldered correctly.
You should get a known good chip to solder into U3100 place.

Also check all resistors related with U3100/200.

 

[nameless]

just received new parts, the replaced was faulty indeed

ALL GOOD NOW

works like a charm

Thank you 2informaticos

Great support

Feeling empowered by this forum