Acer nitro 5 N20C1 - charge but no boot

[nosfay]

Hello,

I think i've messed up this laptop, originally he was booting, but has a dead screen, keyboard, and one USB port.
I've replaced all, and everything was working, but after putting it back together, it didn't power up.

I've disassembled it , remove battery + cmos reset, and let it unplugged a whole night. It then power up for like a minute (I was on windows screen) then shutdown.

Since, I'm not able to power at all (only once, I've got keyboard lights + fan spinning for maybe 10s, then shutdown).

Battery is fully charged at 16v, cmos battery is 3.2v.

The only thing I got now is the charging led indicator blue for 10s, then quickly blink orange and go back to blue. I cannot found corresponding error code.

I dont see trouble at visual inspection.
I've randomly checked for shorts.
I've did a good IPA cleaning.

What can I do next ? I've found schematics here , motherboard is gh51m la-k862p.

I've got multimeter, DC power supply, ch341a for bios.

Thanks for your help =)

[kalilinux25]

can you check if pin 8 of bios is shorted?

[nosfay]

There is no short on pin 8.

[kalilinux25]

Try flashing a CLEAN ME region bios and test again if that is already tested, we need to focus on enabled signal

[mcplslg123]

Since its dead now,you've to check from beginning.
01.Measure resistance to GND on all coils(no power attached)
02.Measure voltage on all coils
03.Check 19V reaches CLR or not(CLR=Current Sensing Resistor located after 2 dc in mosfets)
04.Check +3V LDO is present or not.

[nosfay]

Coil	Resistance	Voltage
PL1101	52	1.06
PL301	4.1K	3.3
PL501	45K	5.1
PL1801	2.7K	1.9
PLV2	0.3	0
PLV3	0.3	0
PLV4	0.3	0
PLV13	0.3	0
PLW1	33	0
PLW2	33	0
PL1001	12	0
PLH1	38	0
PLA1	13.5	0
PLZ4	1.5	0
PLZ3	1.5	0
PLZ2	1.5	0
PLZ1	1.5	0
PLG1	4.5	0
PLM1	35	0
PLB2	900K	16.7

03.Check 19V reaches CLR or not(CLR=Current Sensing Resistor located after 2 dc in mosfets)

Im not sure what to check, I got 19v after first mosfet near DC jack.

04.Check +3V LDO is present or not.

Where do I get that ?


Weird thing happen during voltage measurement, keyboard lights up for few seconds once (like a normal boot).

EDIT: I've found LDO_3V on board view, but I get 5v on it

[nosfay]

I'm going through power sequence, and I have no voltage at EC_RSMRST# (everything before is fine). Is this possibly BIOS related ?

[nosfay]

Try flashing a CLEAN ME region bios and test again if that is already tested, we need to focus on enabled signal

What do you mean by "ME region bios" ? I've only worked on old laptop with classic bios, but on this model I see 2 chip, xmc qh128ahig near PCH, and winbond 25q16jwsiq near CPU. I'm a bit confused


Sry for multiple post but I cannot find edit button anymore

[mcplslg123]

3V LDO is generated by PU301. Measure voltage on pin17 of PU301. Is it still 5V?
I doubt your multimeter batteries or the multimeter itself. It should be 3V

Th XMC128 chip is your main bios. Any bios on intel architecture has me region in it. This me region is tied to the particular motherboard from where it is copied. Once you flash this copied bios on another board the me region may not be compatible with this mb.
Thats why it needs to be cleaned so that there is no mismatch. If you dont know how to clean it,make a request in bios setion while uploading your bios dump.

[kalilinux25]

3V LDO is generated by PU301. Measure voltage on pin17 of PU301. Is it still 5V?
I doubt your multimeter batteries or the multimeter itself. It should be 3V

Th XMC128 chip is your main bios. Any bios on intel architecture has me region in it. This me region is tied to the particular motherboard from where it is copied. Once you flash this copied bios on another board the me region may not be compatible with this mb.
Thats why it needs to be cleaned so that there is no mismatch. If you dont know how to clean it,make a request in bios setion while uploading your bios dump.

Definitely

[nosfay]

BIOS flashing didnt helpt, I've done it twice to be sure.

I've got 3.3v on pin17 of P301. (+3VP)

Maybe it's related to EC ?


I still don't have EC_RSMRST#, I've checked on UB1 pin 100 and RH214.

Thank you

[mcplslg123]

EC_ON/+1.05ALW present?
Very likely EC_RSMRST# will come up after power switch press.

[nosfay]

EC_ON always present, and I got +1.05valw and +3valw after pressing power switch but that's all.

[mcplslg123]

EC_RSMRST# rises after pressing power button to 3V? You have not confirmed this.

[nosfay]

EC_RSMRST# stay at 0 after pressing power button.

[mcplslg123]

Something is wrong here. EC_RSMRST# should rise to 3.3V. What is the resistance to GND on EC_RSMRST# pin?

Have you checked all the requirements of SIO?

If you have a sio programmer.try to flash EC.

Check whether you've any shorts on switched rails like 3VS/5VS/1.8VS etc.

[nosfay]

Resistance to GND on EC_RSMRST# is 9.5k.


I found no shorts on switched rails.



I'm not sure what requirements of SIO are and cannot flash EC.
However I've done some check on EC (UB1):
+3VLP is present on PIN22,33,96,111,124,125
I have nothing on PBTN_OUT#, even when I press power switch

[nosfay]

I will try to dump EC with my CH341A, any advice or guide on how to do it ? It's a ENE KB9022Q .

[mcplslg123]

Programming ENE with ch341A is bit difficult. ECRST# present on SIO?
The resistance to GND on RSMRST# is fine.

[nosfay]

EC_RST# is at 3.3v always.