Acer Swift SF314-54 charging, not powering up

[mcplslg123]

Re: Acer Swift SF314-54 charging, not powering up

As @mon2 has highlighted, it seems something wrong in RTC circuit. I'll suggest to check these first before jumping on the conclusion of defective KBC. I've never seen a bad EC pulling down RTC circuit. If thats the case here, it'll be rare instance. My doubt goes to PCH instead.

01.Resistance on Q1701-All pins
02.Resistance on G1701 pin2.

If resistance on G1701 jumper,pin2 is low, you are very likely staring at a shorted RTC section of PCH. If you are lucky, it could be a shorted cap on RTC lines.

[reformatt]

Re: Acer Swift SF314-54 charging, not powering up

With Acers with integrated power buttons in the keyboard, you should always rule out that out first. They are the most common failure I see and can hold the on/off line down low. This basically appears as if you are holding the power button down and can be misinterpreted as a faulty EC.

With all Acers (and some Lenovo's too with power button in the keyboard) I first disconnect the keyboard, and trigger it manually with tweezers. So in this one its pin 1 of KB1, short it briefly to ground and test.

[kuupotin]

Re: Acer Swift SF314-54 charging, not powering up

i know one trustworthy guy, who is selling these ics programmed on ebay (pitstopcomputers). just ask him, he will help you out for sure. and give him my best regards, pls

Ok, big thanks. Let's put that behind the ear (finnish saying to keep something in mind)

[rediii]

Re: Acer Swift SF314-54 charging, not powering up

Ok, i'll start to find some vendor who is selling preflashed chips. I'll wait a moment if someone will confirm this fault true.

Big thanks to you 👍

i know one trustworthy guy, who is selling these ics programmed on ebay (pitstopcomputers). just ask him, he will help you out for sure. and give him my best regards, pls

[kuupotin]

Re: Acer Swift SF314-54 charging, not powering up

This line is based on a GPIO pin (general purpose input/output pin).

From the measurements, this pin appears to be defective / damaged.

Do wait on other comments but to me, this KBC controller is damaged and must be replaced. From my (limited) understanding, this is a 8051 based KBC IC that uses firmware that is internal to the device. For this reason, this KBC controller requires a special programming tool.

Some KBC ICs use an external SPI interface flash memory device to boot the firmware.

There are vendors on Ebay, etc. that offer pre-flashed KBC ICs.

Ok, i'll start to find some vendor who is selling preflashed chips. I'll wait a moment if someone will confirm this fault true.

Big thanks to you 👍

[mon2]

Re: Acer Swift SF314-54 charging, not powering up

This line is based on a GPIO pin (general purpose input/output pin).

From the measurements, this pin appears to be defective / damaged.

Do wait on other comments but to me, this KBC controller is damaged and must be replaced. From my (limited) understanding, this is a 8051 based KBC IC that uses firmware that is internal to the device. For this reason, this KBC controller requires a special programming tool.

Some KBC ICs use an external SPI interface flash memory device to boot the firmware.

There are vendors on Ebay, etc. that offer pre-flashed KBC ICs.

[kuupotin]

Re: Acer Swift SF314-54 charging, not powering up

After resistor remove. 0,012V
after mosfet same...

So if KBC is faulty, am I able to replace it or should it be flashed?

[kuupotin]

Re: Acer Swift SF314-54 charging, not powering up

Correct. Pin 106 is driving the GATE pin of the mosfet (2N7002) @ Q1701.

Either this pin or something on this pin is shorting.

Start with removing the pull-down resistor @ R1703.

With no power to the logic board, check the DIODE mode reading again on this pin.

Is it improved ? The reading should be higher. If not, remove the mosfet @ Q1701 and measure again.

If the 'hard short' still remains on pin 106 then the conclusion is that the KBC is defective.

Wait on other comments but believe this KBC controller will then need to be replaced.

After resistor remove. 0,012V
after mosfet same...

[mon2]

Re: Acer Swift SF314-54 charging, not powering up

Correct. Pin 106 is driving the GATE pin of the mosfet (2N7002) @ Q1701.

Either this pin or something on this pin is shorting.

Start with removing the pull-down resistor @ R1703.

With no power to the logic board, check the DIODE mode reading again on this pin.

Is it improved ? The reading should be higher. If not, remove the mosfet @ Q1701 and measure again.

If the 'hard short' still remains on pin 106 then the conclusion is that the KBC is defective.

Wait on other comments but believe this KBC controller will then need to be replaced.

[kuupotin]

Re: Acer Swift SF314-54 charging, not powering up

Indeed. Have not yet checked the schematics.

What is this power rail?

Do you have an adjustable power supply? That can be adjusted to a 1 volt output ( not higher ).

The process is then to inject 1 volt onto this rail and check who heats up.

Yes, you have a power supply ☺️

Am I reading this right?

Signal from RTCRST_ON pin106 tells to switch mosfet Q1701 on. So is there something wrong in mosfet or near?

[mon2]

Re: Acer Swift SF314-54 charging, not powering up

Indeed. Have not yet checked the schematics.

What is this power rail?

Do you have an adjustable power supply? That can be adjusted to a 1 volt output ( not higher ).

The process is then to inject 1 volt onto this rail and check who heats up.

Yes, you have a power supply ☺️

[kuupotin]

Re: Acer Swift SF314-54 charging, not powering up

Pin 106 is 8 ohms or 8k ohms to ground resistance?

If 8 ohms, that is too low and there is a shorted part on that line.

Double check now in diode mode.

Meter in diode mode. No power to the logic board.

Red meter probe to ground.
Black meter probe to pin #106.

What is the measurement?

0,009V something wrong here...

[mon2]

Re: Acer Swift SF314-54 charging, not powering up

Pin 106 is 8 ohms or 8k ohms to ground resistance?

If 8 ohms, that is too low and there is a shorted part on that line.

Double check now in diode mode.

Meter in diode mode. No power to the logic board.

Red meter probe to ground.
Black meter probe to pin #106.

What is the measurement?

[kuupotin]

Re: Acer Swift SF314-54 charging, not powering up

PINS: 16, 17, 37, 67, 124, 125
3,3V

PIN: 111
2,9V

PINS with 0V: no power resistance
100 10k
103 320k
106 8
107 92k
111 2,9/very high
121 10k

Here

[mon2]

Re: Acer Swift SF314-54 charging, not powering up

Resistance and also diode mode meter readings are always with no power to the logic board.

Can you review and update your posted values with no power to the logic board?

[kuupotin]

Re: Acer Swift SF314-54 charging, not powering up

Voltage Injection at this stage of troubleshooting is a clear NO. Exact resistance on 3V/5V coil(no power connected)??

Why not check the basic requirements of KBC first??

Pin125/111/67/124//100/103/106/107/121/16/17/37 of KBC-Voltage measurements. If any of the pins have no voltage, measure resistance as well on those pins.

Printing on the schematics is bit mislaigned on pg24.So make sure you are measuring the correct pins.

PINS: 16, 17, 37, 67, 124, 125
3,3V

PIN: 111
2,9V

PINS with 0V: with power/no power resistance
100 51/10k
103 52/320k
106 7/8
107 20/92k
111 2,9/very high
121 20/10k

[kuupotin]

Re: Acer Swift SF314-54 charging, not powering up

Voltage Injection at this stage of troubleshooting is a clear NO. Exact resistance on 3V/5V coil(no power connected)??

Why not check the basic requirements of KBC first??

Pin125/111/67/124//100/103/106/107/121/16/17/37 of KBC-Voltage measurements. If any of the pins have no voltage, measure resistance as well on those pins.

Printing on the schematics is bit mislaigned on pg24.So make sure you are measuring the correct pins.

280 ohm 5Vcoil.

I don't know 3V coil location.

[mcplslg123]

Re: Acer Swift SF314-54 charging, not powering up

Voltage Injection at this stage of troubleshooting is a clear NO. Exact resistance on 3V/5V coil(no power connected)??

Why not check the basic requirements of KBC first??

Pin125/111/67/124//100/103/106/107/121/16/17/37 of KBC-Voltage measurements. If any of the pins have no voltage, measure resistance as well on those pins.

Printing on the schematics is bit mislaigned on pg24.So make sure you are measuring the correct pins.

[kuupotin]

Re: Acer Swift SF314-54 charging, not powering up

Affs... Lets try this.

[mon2]

Re: Acer Swift SF314-54 charging, not powering up

Am I the only one here who have issues with the pictures shared here? They're way to small. I can't identify anything

You need one of these - pretty sure they sell them on Aliexpress. From one of my favorite TV shows while growing up.