HP G62-460SS - DAAX1JMB8C0 - Turn on condition

HP G62-460SS laptop with DAAX1JMB8C0 motherboard.

Situation: Laptop without battery (the client does not have it), connected to the power supply.

When connecting the power supply, the power jack led lights up, but if the power button is not pressed, when some time passes, sometimes after 10 seconds and other times after 60 seconds, the power jack led turns off and The laptop no longer responds to the power button. If I remove power and put it back on, the Jack Power led turns on again, but if I continue without pressing power, the cycle repeats itself.

On the other hand, if when I connect the power and the Jack power led lights up, if at that moment while it is on, I press the power button, the laptop turns on and works without any problem all the time. I can turn the computer off and on as many times as necessary, and it doesn't show any anomalies, even if I turn it off and leave it off, as long as I don't remove the power the laptop works fine and the jack power led no longer turns off.

At the moment, that I remove the power and reconnect, it returns to the same situation of the 2 mentioned operations.

It has been tested with different original power supplies, and the situation is always the same.
Any recommendation?

PD: This fault is the continuation of a previous repair, which has returned. In the previous thread, helped by my colleague Matic, he asked me for the following measurements, which I could not provide because the laptop was withdrawn as it was apparently working well.
He asked me for the measurements in PU4 of pins 1, 3, 4, 6, 7, 13, 27, 28. The value of pin 1 of PD14 and of coils PL5 and PL9.

The values are the following:
PU4:
Pin1 ... 2V
Pin3... 4,96V
Pin4... 13,42V
Pin6... 18,85V
Pin7... 5V
Pin27... 4,92V
Pin 13 y 28...0V
Pin 1 PD14, PL5, PL9 ... 0V

Measure the voltages on pins 14, 17, 24, 27 of PU4

Thanks for your answer and your help.
Pin 14 ... 4,8V
Pin 17... 4,4V
Pin 24... 4,9V
Pin 27... 4,8V

Does the chip PU4 heat up when the problem occurs?

Now I have the motherboard alone on the table, I connect the power adapter and the jack led does not light up. The values are those indicated in the previous posts and the PU4 chip is not hot

matic написав:¿El chip PU4 se calienta cuando ocurre el problema?

No

Measure the resistances to ground on all pins of chip PU4.

Measurement made on a diode scale with a red tip to Ground:
Pin 1: 560
Pin 3: 478
Pin 4: 671
Pin 5: Open
Pin 6: 422
Pin7: 483
Pin9 y 10: 137
Pin11: Short (0)
Pin12: 604
Pin13: 467
Pin 14: 559
Pin 15: 610
Pin 16: 137
Pin17: 567
Pin 18: 590
Pin19y20: 483
Pin23: 590
Pin24: 568
Pin25:142
Pin26:613
Pin27: 560
Pin 28:468
Pin30: 142
Pin31: 604
Pin 32: 478

Is the value of pin 11 normal?
PR56 and PR59 do not physically exist on the motherboard

EDIT: When the board is without current, the resistance in PL5 and PL9 is high, but if I connect power, I remove it again and measure in the coils, the resistance is low, being in PL5... 7 and in PL9... 14
When some time passes without power, in PL9 the resistance increases to 142 and in PL5 it has also risen to 29 but it continues to be low at the same time and remains much longer.
In the +5VPCU line, I think there must be some component that when power comes in, it shorts.
I am going to raise PL5 and inject current in +5V_ALWP, to see how it reacts

Zemog написав:Measurement made on a diode scale

Who asked you about the voltage drops? Please, specify the resistances as suggested.
Make sure the power supply is disconnected from the board for at least 2 minutes before taking the measurements.

Zemog написав:Is the value of pin 11 normal?

No, it's not normal. Also measure the voltage drop on this pin with a reversed polarity of test leads. And measure the resistance as already suggested.

Zemog написав:EDIT: When the board is without current, the resistance in PL5 and PL9 is high, but if I connect power, I remove it again and measure in the coils, the resistance is low, being in PL5... 7 and in PL9... 14
When some time passes without power, in PL9 the resistance increases to 142 and in PL5 it has also risen to 29 but it continues to be low at the same time and remains much longer.

First of all write the measurement units, because we don't know what means the measurements 7, 14, 142 or 29 without the units. Measurement 7 may mean 7Ω, 7kΩ, 7mV, 7µH or maybe 7V ?

Zemog написав:EDIT: When the board is without current, the resistance in PL5 and PL9 is high, but if I connect power, I remove it again and measure in the coils, the resistance is low

The capacitors on the motherboard may stay charged after unplugging the power supply, which may cause incorrect resistance measurements.

Pin1: 120k
Pin3: 204k
Pin4: 148k
Pin5: OPEN
Pin6: 500k
Pin7: 204k
Pin9,10: 19,8k
Pin11: 0 Ohm
Pin12: 304k
Pin13: 14k
Pin14: 300k
Pin15: On a 20MOhm scale, slowly rising to over 20M
Pin16: 19,4k
Pin17: In 20MOhm scale, mark as open
Pin18: 15M
Pin19,20: 200k
Pin23: 15M
Pin24: More than 20M
Pin25: 30k
Pin26: 320k
Pin27: 297k
Pin28: 14,6k
Pin30: 29,7k
Pin31: 198k
Pin32: 199k

In a junk plate drawer I found a similar plate, but instead of being UMA it is Discrete. I have tried to feed it and it generates 3V and 5V. I have measured the resistance of pin11 and it is the same, with which it is normal.

It has caught my attention that on this scrap board, on pin15, on the 2M scale it gives me a value of 31k, and on the other hand, on the 200k scale, it keeps going up until it exceeds 200k. Still, there is a lot of difference from the other board on the same pin.

Replaced PQ54 and PQ49, and problem solved. The laptop is working at 100%

Thanks