acer aspire a515-51g c5v01 no power

[funybux]

hi everyone!,
I'm looking for help to repair this motherboard, I followed a few threads and many youtube videos but still, I cannot figure it out

Reason: Liquid Damage

Model: acer aspire a515-51g
Motherboard: C5V01 LA-E892P REV: 1A

I already make some tests:

ON/OFFBTN 3.2V OK
EC_ON 3.17V
SPOK 2.15mV
SOC_RTCRST 3.006V

PL401/402 no power
PQ403 19.6V

PU401 PIN
6 - 0.03mV
7 - 1.16mV
8 - 0.11mV
9 - 4.6V
10 - 0.05mV
11 - NO POWER

EN 0.03mV

RB 0.03mV
DB1 (chip side(left)) 7.55mV, right 0.06mV

I need your help.

Thanks in advance.

[funybux]

Re: acer aspire a515-51g c5v01 no power

sorry forgot to mention.

after the motherboard is damaged, the power led is on and the fan spins one time then it stops and near the GPU this marked area, both r22 coils are heated. A few times this happened now no power

[funybux]

Re: acer aspire a515-51g c5v01 no power

hi, Does anyone have a solution or idea?

[mcplslg123]

Re: acer aspire a515-51g c5v01 no power

3V_EN_R Present?? PQ302/303 voltage on Pin1/4/8??

[funybux]

Re: acer aspire a515-51g c5v01 no power

3V_EN_R Present?? PQ302/303 voltage on Pin1/4/8??

Hi, thank you for your response

3V_EN_R 0.02mV

PQ302 PIN
1 - 19.6V
4 - 25.59V
8 - 19.6V

PQ303 PIN
1 - 19.6V
4 - 25.59V
8 - 19.6V

[Sephir0th]

Re: acer aspire a515-51g c5v01 no power

Probably multiple issue to solve. I'd need a overview about voltages (nothing except 19V and 3V LDO present) and especially resistances of each power rail. Check at least the coils.

Otherwise iirc on this board 3.3V and 5V come up only after power press. So first thing you should do is to check whether the power button does indeed still work as expected.

[funybux]

Re: acer aspire a515-51g c5v01 no power

Probably multiple issue to solve. I'd need a overview about voltages (nothing except 19V and 3V LDO present) and especially resistances of each power rail. Check at least the coils.

Otherwise iirc on this board 3.3V and 5V come up only after power press. So first thing you should do is to check whether the power button does indeed still work as expected.

"Probably multiple issue to solve"

power button is working. before press 3.3v, after press 0v

[funybux]

Re: acer aspire a515-51g c5v01 no power

Probably multiple issue to solve. I'd need a overview about voltages (nothing except 19V and 3V LDO present) and especially resistances of each power rail. Check at least the coils.

Otherwise iirc on this board 3.3V and 5V come up only after power press. So first thing you should do is to check whether the power button does indeed still work as expected.

hi I appreciate your time,

if i update voltages on these pins PU301, PU501, PU401, is it enough for checking?

resistance to ground 474.1k

and sorry actually i don't know how to check the resistances of each power rail. i can check component resistances but have no idea how to check on rails. can you guide me to check that?

[mon2]

Re: acer aspire a515-51g c5v01 no power

how to check the resistances of each power rail.

Remove all power / no battery.

Meter in resistance mode.

Place one meter probe onto one side of the inductor / coil. Other meter probe to ground. Record the measurement and meter scale used for the test.

If the resistance is very low, the local power rail may be shorting due to a defective capacitor or another component.

Each coil / inductor is linked to a local power supply rail.

If your meter shows a '1' or 'OL' then switch to a higher resistance scale on your meter till you can measure a proper resistance value.

[funybux]

Re: acer aspire a515-51g c5v01 no power

Remove all power / no battery.

Meter in resistance mode.

Place one meter probe onto one side of the inductor / coil. Other meter probe to ground. Record the measurement and meter scale used for the test.

If the resistance is very low, the local power rail may be shorting due to a defective capacitor or another component.

Each coil / inductor is linked to a local power supply rail.

If your meter shows a '1' or 'OL' then switch to a higher resistance scale on your meter till you can measure a proper resistance value.

hi mon2, i appreciate your support and guidance

[mcplslg123]

Re: acer aspire a515-51g c5v01 no power

Resistance on 3V LDO??

[funybux]

Re: acer aspire a515-51g c5v01 no power

Resistance on 3V LDO??

hi, please check the attachment, im not sure i measured correctly.

[funybux]

Re: acer aspire a515-51g c5v01 no power

Probably multiple issue to solve. I'd need a overview about voltages (nothing except 19V and 3V LDO present) and especially resistances of each power rail. Check at least the coils.

Otherwise iirc on this board 3.3V and 5V come up only after power press. So first thing you should do is to check whether the power button does indeed still work as expected.

hi, please check the attachment

[mcplslg123]

Re: acer aspire a515-51g c5v01 no power

Measure resistance og +3v LDO directly on PU401(PC401). Is 3v present there?? If present, remove DB1 & RB17. Now check again whether you get 3v_En_R on pin1 of RB16

[funybux]

Re: acer aspire a515-51g c5v01 no power

Measure resistance og +3v LDO directly on PU401(PC401). Is 3v present there?? If present, remove DB1 & RB17. Now check again whether you get 3v_En_R on pin1 of RB16

resistance - ldo3 25.27k

Is 3v present there? yes

removed DB1 & RB17 but still 3v_En_R 0v

[funybux]

Re: acer aspire a515-51g c5v01 no power

any help

[mon2]

Re: acer aspire a515-51g c5v01 no power

3v_En_R is driven by KB9022. Confirm that UB1 is being powered.

[funybux]

Re: acer aspire a515-51g c5v01 no power

3v_En_R is driven by KB9022. Confirm that UB1 is being powered.

thank you for the response.
ub1 has power but +3VLP_EC is showing 0.0054v

[mon2]

Re: acer aspire a515-51g c5v01 no power

Very good. LB1 must be defective. Can you check the voltage on both sides of LB1 inductor ?

This not a critical part and if required, can be bridged with a piece of wire (after power is removed of course) for testing.

Update:

My power path flow may be in error but you are on the proper track.

The +3VLP_EC has to receive power to power the GPIO pins on VCC_IO2 bank. If this rail is 0 volts, then the batch of GPIO pins on UB1 will not be powered.

See attached.

[phonesafept]

Re: acer aspire a515-51g c5v01 no power

Hi, this issue was solved, i have exactly the same problem, with the same model!

Thank you