820-02098 Stuck at 5v after water damage

[yair37]

5v on charger, not enter to DFU,
PPVBAT_AON_CHGR - 12v
PPDCIN_AON_CHGR 5v
P3V8AON - 0v
i dont get any voltage from all AWAKE or somthing around U8100 and U7700.
didnt find any short on the board..

 

[2informaticos]

Diode mode to ground at 3V8_AON?
Also check at 3V3/5V_S2.

Check LDOs at U8100 and U7700; voltage and diode mode to ground.

 

[yair37]

3V8_AON - 180
3V3_s2 - 430
5V_S2 -360

at U8100 i can chack just one LDO, all the rest its point under the chip
PP1v8_S2SW_CLVR_VDD1_LDO - 490 - 0V
and all the LDO's are under U7700 and cant check them.

 

[2informaticos]

If a LDO is used, MUST go somewhere else, where is needed.
You should find at least one capacitor as test point.
For example, C8180 for MPMU's VCORE.

Compare diode mode reading at 3V8_AON with good board.

If any LDO is shorted, this will block 3V8_AON power supply.
Post U5700 basic voltages; pins 8, 7, 5, 12.

 

[yair37]

on U5700 therE is black stiker so i didnt see that and of cource under it there was corrosion (u5700)

 

[yair37]

ok, update, i was replaced U5700 and make some wires under, no i get all the secoundery voltage(3.8v 5v...)
but still 5v on charge and no AWAKE voltage and still dont find any other components that lead to LDO's

 

[yair37]

im also dont gat PP5V_S2_MAIN(no short -300)
from where i get the 5V_MAIN?

 

[2informaticos]

5V_S2 appears later.
You must get PMUs master /slave LDOs first.

"still dont find any other components that lead to LDO's"
Really???
PP3V3_S2 is an U8100 LDO; did you look at C8161 and other components in pages 57, 70, etc?

 

[yair37]

PP3V3_S2(C8161) 0V - 400
PP1V8_S2SW_CLVR_VDD1_LDO 0V - 400

 

[2informaticos]

I gave you ONE example about how to find ONE LDO.
Still can't find test points for other LDOs?

 

[yair37]

No, can you please teach me how can I find points like that at the scheme?

 

[2informaticos]

Follow the name of the line in schematic, until you find another component connected there.
Then locate it using the boardview...

 

[yair37]

U8800
PP1V8_S2SW_CLVR_VDDC1_LDO 480 0V
PP3V3_AON 370 0V
PP0V8_S2_CLVR_VDDDIG 260 0V
PP1V8_AON 1.8V
PP1V2_AON 1.2V
PP1V5_AON 1.5V
PP3V8_AON_MPMU_ISNS 3V 160
PP1V2_S2 240 0V

U7700
PP3V8_AON_SPMU_ISNS 0.045 weak short..

 

[2informaticos]

"PP3V8_AON_SPMU_ISNS 0.045"
PP3V8_AON_SPMU_ISNS comes from main 3V8_AON, where you've said:
"3V8_AON - 180"
So, what's the true?

 

[yair37]

i dont know but now 3v8_aon is 0.080 i was inject some voltage but nothing is getting hot..

 

[2informaticos]

With 0.080 nothing will get hot.
However, this reading is not good.
A performant IR camera may help you.

 

[yair37]

i was try with performant IR camera also but nothing.. ):

 

[2informaticos]

You need really performant one.
There will be very low temperature differences.
Inject 4V and give time...

 

[yair37]

U8100 was short(cracked) can i take from good know board?

 

[2informaticos]

Yes, donor board.
M1's 14" & 16" PMICs are compatible.