Acer Swift sf314-51-55 doesn't start

[giulio93]

Re: Acer Swift sf314-51-55 doesn't start

Now for no reason the battery is At 3V and At the vin of the step down I have the 19V but no other tension (missing 3.3 and 5V)

[giulio93]

Re: Acer Swift sf314-51-55 doesn't start

A faulty battery can cause this tipe of issue?

[giulio93]

Re: Acer Swift sf314-51-55 doesn't start

If I remove the ldo power supply 1225c and I inject in the 5V line and 3.3V line, should I get an Amps absorbption or I should get 0 A?

[mcplslg123]

Re: Acer Swift sf314-51-55 doesn't start

So you have VIN at 1225C now? Then you should get atleast 3V LDO. Are you getting it? Status of 5V LDO? When triggered, do you get Enable for 1225C?

Acer have typical Thermal Protection fault and i'll help you in bypassing that. First you answer my question clearly.

[giulio93]

Re: Acer Swift sf314-51-55 doesn't start

So you have VIN at 1225C now? Then you should get atleast 3V LDO. Are you getting it? Status of 5V LDO? When triggered, do you get Enable for 1225C?

Acer have typical Thermal Protection fault and i'll help you in bypassing that. First you answer my question clearly.

No, now I have the 19V on Vin, 0.77V in 3.3ldo and i dont know the 5ldo couse the line goes in a via and i dont know where to get the mesurment. I tried to solder a new 1225c chip. A bad chip o bad solder can cause this 0.77V on 3.3 Ldo?

[mon2]

Re: Acer Swift sf314-51-55 doesn't start

0.77V in 3.3ldo

Remove all power. Meter in resistance mode. Measure the resistance to ground of the 3.3LDO rail.

What is the measurement?

[giulio93]

Re: Acer Swift sf314-51-55 doesn't start

Remove all power. Meter in resistance mode. Measure the resistance to ground of the 3.3LDO rail.

What is the measurement?

Tomorrow I Will mesure but it was Kohm

[mcplslg123]

Re: Acer Swift sf314-51-55 doesn't start

3.3V LDO is supposed to be generated by 3/5V PWM IC and the requiremnt is presence of VIN only. The moment it gets VIN, it'll release 3V LDO. Since its being pulled low, either the PWM ic is bad/badly soldered and /or there is some shorted component on 3.3 LDO rail. So the resistance measurement on 3V LDO should give clue. Usually 3V LDO rail is used for SIO/PWR BTN/RTC circuit.

[giulio93]

Re: Acer Swift sf314-51-55 doesn't start

3.3V LDO is supposed to be generated by 3/5V PWM IC and the requiremnt is presence of VIN only. The moment it gets VIN, it'll release 3V LDO. Since its being pulled low, either the PWM ic is bad/badly soldered and /or there is some shorted component on 3.3 LDO rail. So the resistance measurement on 3V LDO should give clue. Usually 3V LDO rail is used for SIO/PWR BTN/RTC circuit.

It is not necessary a enable signal? If the resistance in the 3.3ldo is Kohm how can be interpretate the 0,77V? Bad IC soldering? Could be that?
Other question, I notice that the solder has huge adesion problem on the IC pin. Does exist a Liquid or something that allows to make a good adesion between the solder and the pins? I already use flux

[mcplslg123]

Re: Acer Swift sf314-51-55 doesn't start

No Enable is required to generate 3V LDO(There are exceptions but rare). I use good quality BGA flux to solder these type of IC. The quality of the flux is very important.

[mcplslg123]

Re: Acer Swift sf314-51-55 doesn't start

Another question, does the 3v reulator is geeting a bit hotter then usual?

[giulio93]

Re: Acer Swift sf314-51-55 doesn't start

No Enable is required to generate 3V LDO(There are exceptions but rare). I use good quality BGA flux to solder these type of IC. The quality of the flux is very important.

I use amtech 223. For every other component works Perfect. Just The pins of this chip are dodgy.. A bad solder can couse this 0.77V?

[giulio93]

Re: Acer Swift sf314-51-55 doesn't start

Another question, does the 3v reulator is geeting a bit hotter then usual?

No hot At all

[mon2]

Re: Acer Swift sf314-51-55 doesn't start

Are you confident that you are probing pin # 3 = VREG3 = 3v3 LDO ?

Attached is the top side view of the component.

Also, you have sourced the 'C' version of the component?

[giulio93]

Re: Acer Swift sf314-51-55 doesn't start

I resolder the chip, now i am At the start Point. With the DC in plugged and the battery I have the 3.3. Wifh just the DC plugged in I have a 2.8-3.3 At the vin and i Heard a clicking noise. With just the battery i have nothing couse the battery is at 0V. With both bat and DC in plugged The 1225c chip reach the 46deg Like At the beginning. The pc does not start.

[mcplslg123]

Re: Acer Swift sf314-51-55 doesn't start

Check for presence of 19V at CLR with only adapter connected. I doubt you have problem in VIN section/charging IC.

[giulio93]

Re: Acer Swift sf314-51-55 doesn't start

Check for presence of 19V at CLR with only adapter connected. I doubt you have problem in VIN section/charging IC.

What is CLR?

[giulio93]

Re: Acer Swift sf314-51-55 doesn't start

Check for presence of 19V at CLR with only adapter connected. I doubt you have problem in VIN section/charging IC.

I think the R010 is the clr and I have the same fluttuanding voltage. At the 2R2 aboge that o have the 19V

[mcplslg123]

Re: Acer Swift sf314-51-55 doesn't start

YES.That R010 is very likely the CLR(Current sensing resistor). You should have stable 19V here. If your 3v/5V PWM is soldered properly and the chip is ok, then you have problem in charging section.

Take the following steps:
01.Identify the 2 dc-in mosfets and measure voltage on them.
02.Check in resistance mode(both fets) between
A=Source -Drain
B=Source - Gate
C=Gate -Drain
03.Locate the charging IC and check these pins
A=VCC
B=REGN
C=ACOK
D=ACDET
E=CMSRC

Link the schematic so that i can answer better.

[giulio93]

Re: Acer Swift sf314-51-55 doesn't start

YES.That R010 is very likely the CLR(Current sensing resistor). You should have stable 19V here. If your 3v/5V PWM is soldered properly and the chip is ok, then you have problem in charging section.

Take the following steps:
01.Identify the 2 dc-in mosfets and measure voltage on them.
02.Check in resistance mode(both fets) between
A=Source -Drain
B=Source - Gate
C=Gate -Drain
03.Locate the charging IC and check these pins
A=VCC
B=REGN
C=ACOK
D=ACDET
E=CMSRC

Link the schematic so that i can answer better.

Ok, i Will do those mesurements when i come back at home. But i don't understand how the 1225c chip can interfere with the power input circuit