Acer Swift 3 SF314-51 no power up -shorted inductors

[konpdan25]

Hello everyone,

i face a problem with that laptop. The laptop dosnt power up. when i insert 19v a blue led stays solid, pressing the power up button and nothing happens. I make the reset method and still nothing. I disconnect the battery the same. So according previous post i took measurments on the board. I am attaching the photo with the measurments. i noticed that 3 conductors are shorted to ground and this may be the problem. If anyone can help to find the short , or to give me some advice on how to find it , i would be grateful.

[rediii]

Re: Acer Swift 3 SF314-51 no power up -shorted inductors

Hello everyone,

i face a problem with that laptop. The laptop dosnt power up. when i insert 19v a blue led stays solid, pressing the power up button and nothing happens. I make the reset method and still nothing. I disconnect the battery the same. So according previous post i took measurments on the board. I am attaching the photo with the measurments. i noticed that 3 conductors are shorted to ground and this may be the problem. If anyone can help to find the short , or to give me some advice on how to find it , i would be grateful.

how much ohms, these coils are on cpu core rails and shorted regulary?

[konpdan25]

Re: Acer Swift 3 SF314-51 no power up -shorted inductors

I measure 0 ohms. I downloaded the schematic but I am not so familiar. Maybe they are cpu core rails.

[rediii]

Re: Acer Swift 3 SF314-51 no power up -shorted inductors

0.0 ohms between coil and ground? desolder coils and/or mosfets and measure again on cpu AND mosfet side

[konpdan25]

Re: Acer Swift 3 SF314-51 no power up -shorted inductors

No my bad. The resistances are 7 ohm, 10 ohm and 7 ohm at the point That voltaze is zero. The other coils have bigger resistances. I measured the two mosfet of DC input. Both of them have source and drain at 19v and gates 24v.

[rediii]

Re: Acer Swift 3 SF314-51 no power up -shorted inductors

resistance sounds good. you have to check the core enable signals via schematics. maybe you should desolder those mosfets and check resistance between gate-source, drain-source, drain-gate. often pch has logical error, maybe ram is bad or there are missing enable signals. show me schematics please (upload). check the power block and data-clock tables and reconsider them by measurements. often there is an overview which power rail is enabled by which ic and vice versa etc.

[rediii]

Re: Acer Swift 3 SF314-51 no power up -shorted inductors

show me schematics first.

[konpdan25]

Re: Acer Swift 3 SF314-51 no power up -shorted inductors

If you have patience and you can guide me how and where to measure would be awsome. to check resistance of mosfets shoud they desolder? i attach you the schematic.

MOD Edit: Schematic link -> https://www.badcaps.net/forum/showthread.php?t=121098
.

[rediii]

Re: Acer Swift 3 SF314-51 no power up -shorted inductors

If you have patience and you can guide me how and where to measure would be awsome. to check resistance of mosfets shoud they desolder? i attach you the schematic.

just wait a bit, i'll take a look, no sense for overdoin' things now. i'll try but i have to cook right now. please wait for further steps.

[konpdan25]

Re: Acer Swift 3 SF314-51 no power up -shorted inductors

Yes of course! Take your time!

[rediii]

Re: Acer Swift 3 SF314-51 no power up -shorted inductors

one advice: acer machines have the power button integrated in the keyboard... these often go bad. try to power up the machine via tweezers or did you already? sheet 31. short PWR_SW# with ground and take a look. also measure PWR_SW# and post reading

[konpdan25]

Re: Acer Swift 3 SF314-51 no power up -shorted inductors

OK, well according to schematic we have problem. The con3101 at pin 27 without the ribbon has 200milivolt. I shorted to ground nothing. Pin 1 3.3volt. Pin 2 ground. Pin 3-10 3.3v pin 11 - 26 0v pin 28 0v

[rediii]

Re: Acer Swift 3 SF314-51 no power up -shorted inductors

are you sure you shorted long enough? try without battery and disconnect cmos battery. disconnect everything except screen. don‘t get confused with left and right side of the connector

[konpdan25]

Re: Acer Swift 3 SF314-51 no power up -shorted inductors

Pin no. 1 is on the right?? As we see the picture??

[rediii]

Re: Acer Swift 3 SF314-51 no power up -shorted inductors

OK, well according to schematic we have problem. The con3101 at pin 27 without the ribbon has 200milivolt. I shorted to ground nothing. Pin 1 3.3volt. Pin 2 ground. Pin 3-10 3.3v pin 11 - 26 0v pin 28 0v

ok, that means we are missing +3va. just give me a moment

[rediii]

Re: Acer Swift 3 SF314-51 no power up -shorted inductors

Pin no. 1 is on the right?? As we see the picture??

the arrow is indicating pin 1, thats fine

[konpdan25]

Re: Acer Swift 3 SF314-51 no power up -shorted inductors

OK so the measurements Tha I posted are right!

[rediii]

Re: Acer Swift 3 SF314-51 no power up -shorted inductors

check TPS51225CRUKR-voltages, +3 va +5 vao and generated singals +3 vs +5 vs (i doubt they are present but check), check susc#_pwr, vsus_on, force_off_pwr and sus_pwrg. refer to power table page 94

[rediii]

Re: Acer Swift 3 SF314-51 no power up -shorted inductors

mainly check all signals for 3V/5v-regulator. especially the enable signals, page 81

[konpdan25]

Re: Acer Swift 3 SF314-51 no power up -shorted inductors

OK so from the measurements I took we have problem with the TPS51225CRUKR. And in the try to measure again I made a short and now the chip is dead some pins. I checked for the chip but is unavailable at ti and mouser. Any suggestions?