Acer No power A4WAB LA-C341P REV 1.0

[kalilinux25]

Laptop was water damage so Ive change the PU301 and the pq302 after a day it was not working again Ive check the PQ302 pin 1 it has 15v only.


mb: a4wab la-c341p rev 1.0

checking the pins of the PU301

1. ACN - 19V
2. ACP - 19V
3. CMSRC - 15V
4. ACDRV - 17V
5. ACOK -17V
6. ACDET - 2.5V
7. IOUT -0V
8. SDA - 3.2V
9. SCL - 3.2V
10- ILIM - 0V
11.BATDRV - 21V
12. SRN - 19V
13. SRP - 19V
14. GND - 0V
15. LODRV - 0V
16. REGN - 6.1V
17. BTST - 19V
18. HIDRV - 19V
19. PHASE - 19V
20. VCC - 20V


Hope someone can Guide me where to look next ?

[kalilinux25]

Re: Acer No power A4WAB LA-C341P REV 1.0

the schecmatic

[mon2]

Re: Acer No power A4WAB LA-C341P REV 1.0

Check the ILIM parts on pin 10 of pu301. This should be a non-zero value.

Also confirm pu401 and pu402 on the next page of the schematics are working to produce their respective power rails. They are required to configure the ILIM resistor voltage divider circuit.

[Sephir0th]

Re: Acer No power A4WAB LA-C341P REV 1.0

Also 17V ACOK is a weird value. Should be more likely around 3.3V

[mon2]

Re: Acer No power A4WAB LA-C341P REV 1.0

Agreed on the pin 5 reading. Check for a solder short to pin 4 on this IC.

[kalilinux25]

Re: Acer No power A4WAB LA-C341P REV 1.0

Check the ILIM parts on pin 10 of pu301. This should be a non-zero value.

Also confirm pu401 and pu402 on the next page of the schematics are working to produce their respective power rails. They are required to configure the ILIM resistor voltage divider circuit.

PU401
1.BS- 2.8V
2,3,4,5 - 19V
6. LX - 0V
7. GND
8. GND
9. PG -0V
10. NC - 1.3 not stable
11. EN2 - 4.5V
12. EN1 - 0V
13. FF- 0V
14. OUT - 0V
15. NC - 1.6V not staable
16. NC -3.3V
17. LDO - 3.3V
18. GND - 0V
19. LX - 0V
20. LX - 0V




PU402
1. BS - 8.5V
2,3,4,5, - 19V
6. LX - 5.1V
7. GND
8. GND
9. PG- 0V
10. NC - 0V
11. EN2 -4.5V
12. EN1 - 3.2V
13. FF -0V
14. OUT -5.1V
15. LDO - 5.1V
16. NC - 0V
17. VCC - 3.3V
18. GND
19. LX - 5.1V
20. LX -5.1V

[kalilinux25]

Re: Acer No power A4WAB LA-C341P REV 1.0

Agreed on the pin 5 reading. Check for a solder short to pin 4 on this IC.

No solder short checking resistance to gnd at pin 4 no reading in diode mode

[mon2]

Re: Acer No power A4WAB LA-C341P REV 1.0

3v_en = pu401_pin 12 is not correct to enable this required power rail.

Trace it back and post the voltage at R2627, pin 1.

[kalilinux25]

Re: Acer No power A4WAB LA-C341P REV 1.0

3v_en = pu401_pin 12 is not correct to enable this required power rail.

Trace it back and post the voltage at R2627, pin 1.

R2627 pin 1 has no voltage at all sir..

[mcplslg123]

Re: Acer No power A4WAB LA-C341P REV 1.0

CMSRC at 15V is not correct.Should be stable 19V. Check CLR both sides voltage.

[kalilinux25]

Re: Acer No power A4WAB LA-C341P REV 1.0

CMSRC at 15V is not correct.Should be stable 19V. Check CLR both sides voltage.

Where to find CLR sir?

[mon2]

Re: Acer No power A4WAB LA-C341P REV 1.0

Voltage @ r2626, pin 1? Pin 2?

[kalilinux25]

Re: Acer No power A4WAB LA-C341P REV 1.0

Voltage @ r2626, pin 1? Pin 2?

PIN 1 AND 2 OF r2626 are 0v sir

[mon2]

Re: Acer No power A4WAB LA-C341P REV 1.0

1) Meter in resistance mode (ohms). Black to ground. Red to pin 2 of PL402.

Reading for this coil to ground in ohms ?

2) From my understanding, KB9022QC-A3_LQFP128_14X14 is using its GPIO port pin to create the 3V_EN_R signal. This same signal offers a weak pull-down to keep the switching regulator OFF (as a default). The weak pull-down is @ R2627. Be sure that this R2627 resistor is not shorted to ground. It is supposed to be a 1M resistor.

Aside from this logic flow, perhaps the KB9022QC needs to be reflashed but I have zero experience with this topic. Best to wait on other feedback on the subject.

The KB9022QC appears to be working at least partially since the same controller is used to enable PU402 via 5V_EN = EC_ON pin. That is, the KB9022QC creates the EC_ON logic level and your 5V_EN is ok and so is the rail expected out of PU402.

Baffled as to why KB9022QC is not allowing for the 3V_EN_R pin to be high. Do inspect R2627 to be sure the value is ok @ 1M ohms and there is no short to ground - you can even remove it out of circuit and see if this pin goes high or not.

I think it is even safe for you to consider (unless someone objects), to remove R2626 and then apply a +3v3 rail onto the pad # 2 of R2626. This should then create the logic '1' (logic high) to enable the 3V_EN to enable PU401.

However, follow the other suggestions first and consider this idea to see if PU401 turns on or not. If PU401 works then you know for sure that the KB9022QC needs to be reflashed.

The above idea is to force PU401 to create the +3VALWP rail.

[kalilinux25]

Re: Acer No power A4WAB LA-C341P REV 1.0

It has 1m resistor value then it is not shorted to ground, I'll just wait if its realy good Idea to pump power to its system

[mon2]

Re: Acer No power A4WAB LA-C341P REV 1.0

No, not pumping power into the system but removing the enable pin which is presently outputting a logic LOW '0' (0 volts) -> this is keeping the respective switching regulator disabled.

After you remove this series resistor, you can apply +3v3 from another point on the logic board to change this enable pin to be logic HIGH '1' which in turn should enable the voltage rail.

So the power will not be from an outside source but rather the same logic board.

If that works, which in theory should - then you must reprogram the KB9022QC controller IC.

[kalilinux25]

Re: Acer No power A4WAB LA-C341P REV 1.0

No, not pumping power into the system but removing the enable pin which is presently outputting a logic LOW '0' (0 volts) -> this is keeping the respective switching regulator disabled.

After you remove this series resistor, you can apply +3v3 from another point on the logic board to change this enable pin to be logic HIGH '1' which in turn should enable the voltage rail.

So the power will not be from an outside source but rather the same logic board.

If that works, which in theory should - then you must reprogram the KB9022QC controller IC.

As far as I can understand,
1. Remove the R2626 and R2627?
2. Plug the mb to powersource 19v
2. then supply it with 3.3v ?

[mon2]

Re: Acer No power A4WAB LA-C341P REV 1.0

Which of the following is stuffed?

PR324 or PR316?

These resistors configure ILIM for pu301.

What is the voltage on pin #2 of the stuffed resistor?

Then post the voltage on pin #1 of the resistor.

[kalilinux25]

Re: Acer No power A4WAB LA-C341P REV 1.0

Which of the following is stuffed?

PR324 or PR316?

These resistors configure ILIM for pu301.

What is the voltage on pin #2 of the stuffed resistor?

Then post the voltage on pin #1 of the resistor.

PR324 is non stuff

Pin 1 of P316 no voltage
Pin 2 of P316 has 3.3v

[mon2]

Re: Acer No power A4WAB LA-C341P REV 1.0

PR316 is bad.

Power down and check the resistance of this resistor.