Acer Nitro 5 3valwp short 1ohm

[Thomas8607]

Hi all!

I have an acer nitro 5 notebook. The 1,05v, 1,8v and 3valwp were short.
I injected 3v on 3v rail and the pch was hot,i desoldered it.
The 1,8 and 1,05v are ok now, but the 3v still shorted.

The 3v to ground resistance is 1ohm (not zero).

Where do i find the fail?
I have schematic and boardview too.


Thanks!

[mcplslg123]

Re: Acer Nitro 5 3valwp short 1ohm

Should'nt have injected more then 1V. Injecting 1V again on the shorted rail doesnt heats up anything? My doubt goes towards EC. Howver, i'm not very hopeful if 1.05V/1.8V and 3.3V rail were all shorted together as chances of cpu getting hit is also very high.

[Thomas8607]

Re: Acer Nitro 5 3valwp short 1ohm

I will try injecting again, with 1v.
I injected 3v to 3v rail, so with 1v nothing happened.
I hope, that the cpu survive this.
Thanks!

[Thomas8607]

Re: Acer Nitro 5 3valwp short 1ohm

I've found a hot component. UL1, this is the LAN power supply ic, I've removed it. Now i'm measuring 11,8ohm resistance on 3valw.
EC isn't warm

This resistance is low.

[mcplslg123]

Re: Acer Nitro 5 3valwp short 1ohm

Yes, resistance is still way below normal. This imples there are other shorted components also. This may lead you to rabbit hole with such kind of simultaneous shorting on different rails. Voltage injection is the only way you can findout shorted component and there lies the catch as you cant inject more then 1V. Dc supply with 10A helps a bit in such scenarios.

[Thomas8607]

Re: Acer Nitro 5 3valwp short 1ohm

There are some components on 3v rail,
I will try these desoldering
Um1 wlan
Uk1 touchpad
Uk2 fingerprint?
Um2?
Uq1?
Pj1001

There is a problem with voltage injection, the ohm law.
1V/10ohm = 0,1A this is 0,1W power
Or not?

[Thomas8607]

Re: Acer Nitro 5 3valwp short 1ohm

Sound ic was dead 😀
Now i'm measuring 140ohm. This is low too ☹️

[mcplslg123]

Re: Acer Nitro 5 3valwp short 1ohm

Remove all usb controller/diodes,sound,lan,card reader chips and then measure resistance to GNd again on the affected rail.

[Thomas8607]

Re: Acer Nitro 5 3valwp short 1ohm

I've removed all active components, or jumper(amper measurement point) and measured all resistors, which are connect to +3valw rail. I haven't found failed components.
(usb controller is on 5valw)

I'm measuring 240ohm,but it is without pch. If i will solder the pch, then it is more resistance? (i measure low resistance, because the pch isn't on the motherboard)?

Thanks

[mcplslg123]

Re: Acer Nitro 5 3valwp short 1ohm

Without the PCh soldered, resistance to GND on +3VALW rail should be in Kohms. So there is still faulty component.

[whaldsz]

Re: Acer Nitro 5 3valwp short 1ohm

I've removed all active components, or jumper(amper measurement point) and measured all resistors, which are connect to +3valw rail. I haven't found failed components.
(usb controller is on 5valw)

I'm measuring 240ohm,but it is without pch. If i will solder the pch, then it is more resistance? (i measure low resistance, because the pch isn't on the motherboard)?

Thanks

Remove the coil at +3VALWP and check which side is shorted. It is possible that the 240 ohms resistance you get is from the IC Regulator, or any of the capacitors along that rail.

[Thomas8607]

Re: Acer Nitro 5 3valwp short 1ohm

Remove the coil at +3VALWP and check which side is shorted. It is possible that the 240 ohms resistance you get is from the IC Regulator, or any of the capacitors along that rail.

I've tried it, almost same resistance (more 20ohm).

[Sephir0th]

Re: Acer Nitro 5 3valwp short 1ohm

You got clear advises, so it should be okay to expect you being way more clear with your answers, otherwise nobody will understand you.
And it seems like you still need to realize that you're probably dealing with multiple bad components on the 3.3V rail und you have to get rid of all of them till the 3.3V rail has a healthy resistance to GND again.

[Thomas8607]

Re: Acer Nitro 5 3valwp short 1ohm

Sorry if I write something wrong, my English is bad. I may have said the wrong thing, or they mean it.

I removed and measured the following components and the resistance value did not change. I'm sure I'm missing something, but I can't figure out what.


I measured these:
Q10, Q11, Q12, Q13 next to SIO
PR1009 10K
RH3 10K
RH200 10K
RH201 10K
RH25 1K
RH26 1K
RH27 1K
RH29 100K
RH55 1K
RH56 8K2
RH183 10K
RH251 2K2
RH252 2K2
RH253 2K2
RH254 2K2
RH63 499OHM
RH64 499OHM
RH215 2K2
RH216 2K2
RH217 2K2
RH218 2K2
RB78 10K
R38 100K
R37 100K

I removed and measure resistance on 3valw:
UL1
UM1
UH2
UM2
UK1
UQ1
PCH


I soldered these jumpers apart:
PJ1001
JPB1 (SIO)
PJ2501, PJ2502
PJ302


There must be a faulty part that I missed

Thank you everyone!

[whaldsz]

Re: Acer Nitro 5 3valwp short 1ohm

You've done a lot!

You haven't removed PU301, have you? How about the capacitors prior to +3ALWP? You can also inject up to 3.3v at PL301 then check (via thermal scanner) which one is heating up.

[Thomas8607]

Re: Acer Nitro 5 3valwp short 1ohm

If i've cutted the jumper between 3valwp and 3valw, then i've measured kohm range on 3valwp (on pl301), also capacitors are good.?

I tried lift up coil too.

Thank you!

[Thomas8607]

Re: Acer Nitro 5 3valwp short 1ohm

I will remove the next capacitors:
CH10
CH36
CH39
CH38
CH41
CH42
CH40
CL16
CM15
CK3
C56
C59
CQ7
PC307
PC308
PC309
PC310
PC311
PC312
PC1114
PC1807
PCH14

Or the MLCC capacitors fault not 200ohm?

[Thomas8607]

Re: Acer Nitro 5 3valwp short 1ohm

Or these ICs?
The PCH shorted the 1,05 and 1,8V
Maybe these ics are bad?
I measure a good resistance at the output of their coil, but on the byp pin is the 3valw.

[Thomas8607]

Re: Acer Nitro 5 3valwp short 1ohm

Since it was at the mechanic before me, I looked at the 19v rail as well. After the second FET, I measured 36 ohms. I tried injecting 1V but nothing happened. I raised it to 5V and the ipa disappeared from the 1.05v reg ic. I removed the IC and the 19vb rail and the 3valw (3.56kohm) rail were also fine.

Also i have some bad components:
Sound ic
Lan ic
Lan voltage enable ic
Pch
1,05v reg ic
Charger ic

Now are good all of voltage rails resistance.

[Thomas8607]

Re: Acer Nitro 5 3valwp short 1ohm

I removed Pch, with the power supply there was 5v, after pressing the power button, 3.3v, 1.8v and 1.05v also appeared.
After soldering a new sr40b pch, the resistances are good. Switched on the notebook, the pch again in short circuit (3.3v, 1.8v and 1.05v 0ohm).

The pch is an aliexpress purchase, from a reliable source.
What could be wrong?
Thank you for your help!
LA-H501P