Acer Swift 3 SF314-51 not powering up - leds flashing

[Techtiger]

Re: Acer Swift 3 not powering up - leds flashing

go to page 89 of the Schematic test all voltages in PIC this is the DC to Dc all voltages must be present

[rddube]

Re: Acer Swift 3 not powering up - leds flashing

go to page 89 of the Schematic test all voltages in PIC this is the DC to Dc all voltages must be present

Hi techtiger,

Not sure how or where to check those voltages, the board doesn't have any markings except for a number of JPXXXX points. Can you help me identify which component I should be getting those readings from? I can post a sharper image of the power section of the motherboard if that can help. Tks!

[rddube]

Re: Acer Swift 3 not powering up - leds flashing

Diode is no stuff.
Soldering on the inductor might be because the guy tried to randomly inject voltage there. We can see that there is some solder on the screwhole on the left, where the ground wire was soldered.

At that point most main power rails are present but not CPU VCore, probably a good idea to check the enable signal for CPU VCore regulator.

How would I check the enable signal for CPU VCore regulator? Tks Piernov!

[KvnTM]

Re: Acer Swift 3 not powering up - leds flashing

How would I check the enable signal for CPU VCore regulator? Tks Piernov!

CPU VCore Power Stage Chip is U8002A in Schematic => SIC631CD-T1-GE3
CPU VCore Controller is U8000A in Schematic => ISL95859HRTZ

Your VCore circuitry consists of two separate chips. U8002A is the power stage (marked on the photo) which is driven by U8000A.

You have to find the ISL chip on your board. Maybe there's something in the schematic that is printed onto the board. Finding it would be your job

U8002A:
Pin 1 => PWM Input from ISL Chip.
Pin 32 => VIN = Battery/AC Voltage
Pin 3 => VCC = 5V

U8000A:
Pin 40 => Enable Input of the Controller. (this is what piernov was talking about)
Pin 34 => VCC = 5v
Pin 33 => VIN = Battery/AC Voltage

Be really careful to NOT short any pins on those chips!
Power cycle the board while measuring PWM/Enable pins and look for any changes. An oscilloscope would be great if you have one.

Please post a photo of the ISL area to confirm it is the correct one.

[rddube]

Re: Acer Swift 3 not powering up - leds flashing

Ok, so I tried to locate the ISL chip on my board, not sure if I found it, but here are photos of both sides of my board. The chip identified with a red border is the other Vcore control chip I think, as it has the same markings as the one you identified just below the CPU.

As for the ITE chip, I checked with a magnifier the soldering and it is fine, it's the photos that make it look as if it was worked on but it's good.

If the 3F = 3H chip is not the ISL, not sure where it is unless it is hidden under the heatsink portion - if need be I can remove that and check.

Tks again!

[KvnTM]

Re: Acer Swift 3 not powering up - leds flashing

Ok, so I tried to locate the ISL chip on my board, not sure if I found it, but here are photos of both sides of my board. The chip identified with a red border is the other Vcore control chip I think, as it has the same markings as the one you identified just below the CPU.

As for the ITE chip, I checked with a magnifier the soldering and it is fine, it's the photos that make it look as if it was worked on but it's good.

If the 3F = 3H chip is not the ISL, not sure where it is unless it is hidden under the heatsink portion - if need be I can remove that and check.

Tks again!

Hm looks like both aren't the correct ones.
Take the heatsinks and all shields off. Also take a look at the schematic if you can't find any markings near the chip on your board.

It's really bad design to have close to none markings on the silkscreen. Marking on the chip should be 95859HRTZ. There should be no big coil connected to it since it is only a pwm controller. It also could be on the bottom of your board but im not sure.

[rddube]

Re: Acer Swift 3 not powering up - leds flashing

Before dismantling it, I just took some resistance readings on the caps near that chip you identified, and here is what I get.

Is this normal, or does it look like a short?

Tks.

[KvnTM]

Re: Acer Swift 3 not powering up - leds flashing

Before dismantling it, I just took some resistance readings on the caps near that chip you identified, and here is what I get.

Is this normal, or does it look like a short?

Tks.

Thats normal.
19 & 13 Ohm caps are on a cpu power rail which naturally has a low resistance.
Not quite sure what the 38 Ohm cap is for.. Try to measure the voltage across it.

Does your model have a dedicated gpu?

[rddube]

Re: Acer Swift 3 not powering up - leds flashing

Ok, so didn't wait and dismantled the motherboard (so can't take voltage readings for now).

Here is a photo of both sides of the board without the heatsink. Can't seem to find the chip 95859HRTZ?

What should I check now?

[rddube]

Re: Acer Swift 3 not powering up - leds flashing

Sorry, checked too fast, it is up there on the backside in the upper right corner of the board. It is marked Intersil 95859HRTZ !!

[KvnTM]

Re: Acer Swift 3 not powering up - leds flashing

Sorry, checked too fast, it is up there on the backside in the upper right corner of the board. It is marked Intersil 95859HRTZ !!

Yup! That should be it. Now you can start measuring. I'll try to find a way to power the board without keyboard.

EDIT: Shorting Pin 27 on the keyboard connector to GND will turn the board on
Look for CON3101 in the schematic. Pretty much self explanatory.

Best way would be to solder a fine jumper wire to it.

[rddube]

Re: Acer Swift 3 not powering up - leds flashing

Hey KvnTM, I think I might have found something as I was just probing around the chip to check for shorts, I found the capacitor marked in the photo to be 1.2 ohms, now isn't that a short?

All the others seem fine. Also attaching another photo of the same area that seems a little clearer.

Let me know what you think and thanks!

[KvnTM]

Re: Acer Swift 3 not powering up - leds flashing

Hey KvnTM, I think I might have found something as I was just probing around the chip to check for shorts, I found the capacitor marked in the photo to be 1.2 ohms, now isn't that a short?

All the others seem fine. Also attaching another photo of the same area that seems a little clearer.[ATTACH]203547[/ATTACH]

Let me know what you think and thanks!

Yeah that doesn't sound quite right to me.
It is
C8015
220PF/50V

Remove it and measure the resistance of the cap. Do not power the board after removing it.

[rddube]

Re: Acer Swift 3 not powering up - leds flashing

How were you able to find it was C8015? I looked at the schematic and tried to follow pin 18 of the chip, but I get lost . Ok, I will remove it and report back, tks.

[rddube]

Re: Acer Swift 3 not powering up - leds flashing

Ok, removed it and it is not shorted. I still have 1.2 ohms on the board between the 2 points where it was soldered.

Does that mean that the problem is with the 95859HRTZ ?

[SMDFlea]

Re: Acer Swift 3 not powering up - leds flashing

Could you post a close up of the area marked in the photo

[rddube]

Re: Acer Swift 3 not powering up - leds flashing

Hey SMDFlea, tks for asking. Here you go.

[SMDFlea]

Re: Acer Swift 3 not powering up - leds flashing

its ok ,must have been the flash ,no damage there.

[piernov]

Re: Acer Swift 3 not powering up - leds flashing

Pin 18 appears to be connected to VCORE_VSSSENSE, which is basically connected to ground so that seems fine.

[rddube]

Re: Acer Swift 3 not powering up - leds flashing

Ok, so I replaced the capacitor - what should I do next?

I guess I should do the tests that KvnTM suggested - but before I need to solder a fine jumper wire to pin 27 of the keyboard connector. Dumb question, which is pin 27 do I start counting from the right or the left, as there doesn't seem to be an indication of pin 1?