Acer Spin 3 SP314-54N, Mainboard Lenny_ICL 19771-1 no power,

[master3112]

Hello everyone.
I have an Acer Spin 3 SP314-54N, mainboard: Lenny_ICL 19771-1.
The device does not start. I have 19V at the input of the PU4408 (AON21321). Gate voltage is also 19V but the MOSFET is not opened. I have also replaced the MOSFET and it is OK. The gate voltage is provided by two resistors PR4418 (200k) and PR4419 (100k). I unsoldered both and measured them, all okay.I also desoldered and measured the PC4453, which is OK. I desoldered the PU4408 and short-circuited pads 1-3 with pads 5-8. Then the device started normally. Does anyone know what gate voltage the PU4408 should have? Maybe it is too high and therefore the PU4408 does not open?
The second MOSFET (PU4401) in the 19V rail is also an AON2132 and I have swapped the two with each other but still no change. When I short-circuited the PU4408, the PU4401 had a gate voltage of only 17V. Should the PU4408 also have a gate voltage of 17V?
Does anyone have any ideas and can help me?
Thanks

[rogfanther]

It is a P-channel, so yes, it needs a lower voltage on gate to conduct.

[pc_okay]

Yes, acer reinvent the wheel again using P-Channel mofset.

Check resistance to ground on:
PR4404

Check carrefuly voltage:
AC_DET / DC_IN_OK (3.33V) and PWR_CHG_ACDET (to check if the charger is properly detected)
PWR_CHG_VCC (19V ~) (to check if your IC charge is powered)
PWR_CHG_ACOK (3V ~) to check if your charging system is good to go)
PWR_CHG_REGN (to check if your IC charge is working fine)
PWR_CHG_ACN
PWR_CHG_ACP

report your results please. 😀

[master3112]

Thank you for your support pc_okay.
I have remeasured the values on the PU4403:
Resistance at PR4404 270k
AC_DET / DC_IN_OK (3.33V) I have only 1.3V, I have unsoldered and measured the resistors R4301 and R4302 and they are OK.
PWR_CHG_VCC (19V ~) = 19V
PWR_CHG_ACOK (3V ~) = 0V
PWR_CHG_REGN = 0V
PWR_CHG_ACN = 0.2V
PWR_CHG_ACP = 0.2V
I have also replaced the PU4403 power controller, no change.

[mon2]

The dual diode @ PD4403 is a suspect. This dual diode feeds into the AC_DET pin. Measure the voltage to ground on each leg of this dual diode and share the measurements.

[master3112]

The TWIN diodes PD4403, PD4406, PD4409, PD4411 check whether input voltage is present either via DC socket or USB-C. At one of the inputs of the twin diode, 19V is checked via DC socket 19V_AD_JK and at the other 20V via USB-C 20V_TYPEC1_VBUS20 depending on the operation via USB-C or mains adapter.
In mains operation is 19V (19V_AD_JK) present at PD4406, PD4411.
In mains operation isnt19V (PWR_ADP_19V )present at PD4403 and PD3310, which is also understandable because PWR_ADP_19V is only tapped after PU4408 and this does not open.
With USB-C operation is 20V (20V_TYPEC1_VBUS20) available at PD4403, PD4406, PD4409, PD4411.
I have tested operation via USB-C. The device does not start via USB-C either. I have also desoldered and measured PD4403, PD4406, PD4409, PD4411 and these are OK.
The PU4408 is switched by PQ4402. 19V_AD_JK is present at PIN1 of the PQ4402. At PIN3 of the PQ4402 PWR_ADJK_G there is also 19V which is too much as rogfanther writes. The PQ4402 therefore appears to be open. PQ4402 opens when ground is present at PIN2. When PQ4402 is open, it switches 19V_AD_JK through to the gate of the PU4408 and the PU4408 remains closed. I removed the PQ4402 and had 6V at the gate of the PU4408. The PU4408 was open and the device came on. The PQ4402 therefore appears to be continuously open. PQ4402 is switched by PQ4401 and also via the PD4410 twin diode. PQ4401 is switched by EC U4401. (This Circuit is OK.)
I checked the area of the PD4410 twin diode. I desoldered the PD4410 twin diode and the device started. The gate of the PQ4402 is therefore switched to ground via the PD4410 twin diode. The PD4401 diode can therefore only switch the ground via PQ4405. I reinstalled the diode and desoldered the PQ4405. I have 19V at PIN3 of the PD4410 diode. The device starts via power supply and also via USB-C. This means that the PD4401 is also OK. I have 9V from PD4411 at PIN5 of the PQ4405. So the PWR_CHG_ADPID# signal also seems to be OK, or should there be a different voltage there? Nevertheless, I have ground at PIN3 of the PQ4405. At this point I don't know when and why I have ground at PIN3 of the PQ4405. I have unsoldered PQ4405 and measured PIN4 against PIN3 and have a resistance of 4.7M.
So the problem seems to be only in the control of the PU4408. The PU4408 circuit is actually only switched through this area.

[Biga73]

Exactly the same board. Starts only from battery. I will take measurements later

[pc_okay]

Guys do you try to change dc jack? check voltage on pin 3 supposed to be 0V.
They often break and sometime 19V leaking on pin 3.

Not the same laptop but same fragile connector: (i see some laptop with same problem since this one! easy repair)
https://www.badcaps.net/forum/troubl...b-dc-or-type-c

[master3112]

That's not possible. No way. My device does not have a PIN in the DC socket. Probably broken off. You're right pc_okay the PIN must normally be connected to ground. I have manually connected the pin to ground and the device starts. So much work because of one contact. Thank you for this tip. Now I order a new DC socket. Well, at least I got to know the device in detail

[pc_okay]

Yes if you look inside the DC socket you will see it's slightly damaged maybe you will see a little metal moving part in still attached to the case of the DC...

Maybe it will be a good idea to add the this reccurent problem to the "Sticky:Laptop battery charging circuit" what do you think piernov ?

[master3112]

@pc_okayThat would be a good idea. I did look at the diagram thoroughly when troubleshooting, but I still missed the fact that a circuit checks whether the plug is physically plugged in.

[master3112]

@Biga73What does your device do?

[Biga73]

@Biga73What does your device do?

Sorry for not responding for so long. Replacing the connector DC solved the problem.