A2251 820-01949 Stuck at 5V after water damage

[wtw0987]

I have a board that got a tiny bit of water damage through the air vent on the bottom of the laptop. The laptop was charging when the damage occurred and was at 1% and will not turn back on.

When plugging in an ampmeter after unplugging the battery, the reading starts at 0.087A and slowly goes down to 0.056-0.063A at about 5.14V.

PPBUS_G3H = 12.33V
PP3V3_G3H_RTC = 3.34V

I cleaned the board up with a ton of isopropyl alcohol and also reflowed the U3100_X CD3217 chip but I still have the same issue on all 4 ports. This behavior was occurring before the reflow as well. I also noticed that P3v3_S5 was at 0.01mV but I'm not sure if that is relevant yet or not.

Any help is appreciated!

 

[2informaticos]

First of all, welcome to the forum!

Check diode mode to ground on all big coils; don't forget L9080.
Compare with good board, or reference table.

OpenBoardData Project

 

[2informaticos]

0.084 is really bad; probably dead SSD.
You can remove U9080 and test again.
If still low, then dead SSD for sure.

Injecting voltage there probably doesn't heat anything.
However, a good thermal camera can help you to detect the culprit.
You may need to inject 3V and wait some time.
I recommend to start with just 1V anyway.

 

[wtw0987]

0.13	P2V5_SW2_TPS62180_SSD0
0.133	PP2V5_NAND_SSD0
0.177	PP3V3_G3H_RTC_REG_R
0.456	PPBUS_G3H
0.27	P3V3_S5
0.377	P3V3G3HRTC_PHASE1
0.383	P3V3G3HRTC_PHASE2
0.347	PVCCQ_LX0
0.365	PP0V9_SSD0
0.399	PP1V8_SLPS2R
0.082	PP0V9_SLPDDR
0.254	PP1V1_SLPS2R

Got these values after doing a quick refresher on diode mode (first time if you can't tell haha) Most of these values line up with the reference table aside from those top 3 values. Will take a look at U9080 like you mentioned as well.

 

[wtw0987]

Removed U9080 and got these values for the 3 outliers

0.373	P2V5_SW2_TPS62180_SSD0
0.373	PP2V5_NAND_SSD0
0.371	PP3V3_G3H_RTC_REG_R

The PP3V3_G3H_RTC_REG_R value lines up with the reference sheet but the other two are still a tad off as the reference sheet has those both around 0.425 I noticed the enable pin on the SSD was not getting any voltage when the board was powered, could this be part of the issue?

 

[2informaticos]

The last readings are not so bad.

Check voltage on the small coils surrounding U7800.

Do you get all G3S voltages?

 

[wtw0987]

0.7v	PPVDDCPU_AWAKE
1.1v	PP1V1_SLPS2R
0.87v	PP0V9_SLPDDR
1.8v	PP1V8_SLPS2R
0.82v	P0V82_SLPDDR
0v	PPVNN_PCH_EXT
0v	PVCCPCOREPRIM_SW0
0.8v	PPVDDCPUSRAM_AWAKE
0v	P1VPRIM_SW0
0v	PP1P05_PCH_EXT
0v	PP1V1_S3_REG_R
0v	PP1V1_PHASE
0v	PP1V8_G3S
0v	PP3V3_G3S
0.005v	PP5V_G3S

Here is all the info I could get from that. I haven't put U9080 back on the board yet either if that means anything.

 

[2informaticos]

Put back U9080.
Let the board cools down and check again diode mode at L9080 and PPBUS_G3H.

 

[wtw0987]

PPBUS_G3H 0.458
L9080 0.003

I'm assuming that the SSD is dead? Could also be cause of a bad rework job I'm not the most experienced with air reflow.

 

[wtw0987]

I will also note that the board now pulls .2 amps instead of .06 amps as well when powered.

 

[2informaticos]

Possibly bad U9080, or solders underneath.
Remove the chip and check diode mode directly between its power pads.
Be aware when you flip the chip, will be mirrored on the flip direction; comparing with boardview.

SSD may be good.
You didn't report short to ground on L9080 without U9080 onboard.

 

[wtw0987]

		expected	actual
PPBUS_G3H_SSD0		0.51	0.435
P2V5_SW2_TPS62180_SSD0		0.425	0.346
SSD0_TPS62180_FB		1.413	0.351
SSD0_TPS62180_SS		0.538	.0L
SSD0_VR_P2V5_EN_R		0.64	0.741
SSD0_CR_P2V5_PGOOD		0.565	0.577

This is what I'm getting with U9080 off the board on the pads.

 

[2informaticos]

Are these readings on the board, or U9080 pads?
If are from the board, then replace U9080.
If the short remains on the board, then dead SSD.

BTW, I asked you to check directly on U9080 pads (not on the board); not sure what you really did.

 

[wtw0987]

Are these readings on the board, or U9080 pads?
If are from the board, then replace U9080.
If the short remains on the board, then dead SSD.

BTW, I asked you to check directly on U9080 pads (not on the board); not sure what you really did.

Ah I see sorry wording was terrible there, the readings above are from the logic board without U9080 onboard, here are the readings from the U9080 pads directly from the backside of U9080

PPBUS_G3H_SSD0	0.584-0.6 on all pads
P2V5_SW2_TPS62180_SSD0	0.517
SSD0_TPS62180_FB	1.38
SSD0_TPS62180_SS	0.554
SSD0_VR_P2V5_EN_R	0.643
SSD0_CR_P2V5_PGOOD	0.694

 

[wtw0987]

I put U9080 back on the board after seeing the readings from above and I think it is functional. Here are the readings I got on the logic board with U9080 back on it

		expected	actual
PPBUS_G3H_SSD0		0.51	0.378
P2V5_SW2_TPS62180_SSD0		0.425	0.378
SSD0_TPS62180_FB		1.413	1.383
SSD0_TPS62180_SS		0.538	0.553
SSD0_VR_P2V5_EN_R		0.64	0.64
SSD0_CR_P2V5_PGOOD		0.565	0.58
PP2V5_NAND_SSD0		0.425	0.378

Current draw is up to 0.44 amps but I'm still sitting at 5V when the board is powered.

 

[2informaticos]

Do you get SSD voltages now?
Also check G3S ones.

 

[wtw0987]

GS3 voltages were all still at 0. PP2V5 is getting 3.67V and I also noticed that PPBUS_G3H is now at 4.95V instead of 12V as it was before, U9080 is feeling a bit hot as well but I'm not getting anything weird when measuring the pads for it in diode mode so I'm not sure if there is a short on it or not.

 

[2informaticos]

Pufff, replace U9080.
Pray that SSD is still alive.

 

[wtw0987]

Gotcha, ordered one and will update once I get it and place it on the board. Thank you for the help, it is truly appreciated. This is my first ever repair as a fun side-project.