Acer Swift sf314-51-55 doesn't start

[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.

vcc=18.9
B=6.2
C=0
D=2.6
E=0

for the 2 mosf i think they are those on the right of the current sensor resistor. I have all Kohm mesure but the one connected to the same pad.
and now i have no more vin at the 1225c

[mcplslg123]

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

Remove the CLR and then connect the adapter. Do you get 25V at the gate of both dc-in fets?

[giulio93]

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

Remove the CLR and then connect the adapter. Do you get 25V at the gate of both dc-in fets?

They are no "normale mosfs" with one gate. But no, i dont have the 25V. But i have some 19V around the Board.
And why Now i dont have anymore the vin at the stepdown?

[giulio93]

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

i dont get a thing. the vc in on the 1225c comes directly from the dc in connector or the bq chip has to be activated?

[giulio93]

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

there is any difference between bq735 and bq736?

[mcplslg123]

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

i dont get a thing. the vc in on the 1225c comes directly from the dc in connector or the bq chip has to be activated?

It comes from CLR and not dc jack directly. If you dont have 19V on CLR, you wont get it at stepdown controller. Whether voltage will reach CLR or not, depends on the functioning of charging circuit.

[mcplslg123]

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

there is any difference between bq735 and bq736?

Yes, not compatible.

[giulio93]

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

Yes, not compatible.

At this point i think the problem is the bq. AM i correct?
Do you confirm the 2 input mosfets are the nearby of the clr?
other thing. Why i have not the 19V At the first mosfet?

[giulio93]

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

At least I aspected ti have the 19V on ine of the 2 mosfet

[mcplslg123]

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

That expectation will meet on the board when charging circuit works. Why not give us measurement of charging IC instead of what you expect or think? That'll perhaps help you. Without measurements our guess is as good as yours.

[giulio93]

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

That expectation will meet on the board when charging circuit works. Why not give us measurement of charging IC instead of what you expect or think? That'll perhaps help you. Without measurements our guess is as good as yours.

I already gave you the masure of the charging i you asked me

[giulio93]

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

I'm trying to solder the new bq chip but the solder does not stay on it... I think it is a bar quality chip. Do you have any tips to solve this problem?

[Sephir0th]

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

it's a common issue with these controllers. Try to pre-tin the pads of the IC and try again. it should help till some extent

[mcplslg123]

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

If the IC is new, you have to apply flux on it and put some solder with a irn tip.The solder will stick and pins will shine up. Remove any excess solder with a soldering braid. Now ready to go. Once again apply flux on the pcb pads,align the IC with pcb and then apply heat.It should be properly soldered. Touch up the pins if you doubt any connectivity issues.

[giulio93]

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

If the IC is new, you have to apply flux on it and put some solder with a irn tip.The solder will stick and pins will shine up. Remove any excess solder with a soldering braid. Now ready to go. Once again apply flux on the pcb pads,align the IC with pcb and then apply heat.It should be properly soldered. Touch up the pins if you doubt any connectivity issues.

I've tried but The solder simoly doesnt stay on the pins

[Sephir0th]

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

You need to be more Patient with the pins. It will work after a while.

[giulio93]

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

You need to be more Patient with the pins. It will work after a while.

I stay more then 10sec on each pin with the solder iron

[giulio93]

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

I solder and resoldered manu Times. I get 2.8-3.8v in the current sensor. I have the same tension on the gate of the Second mosfet (i think the Second) and 0 at the first. I dont understand why i have no 19V in the input of the first mosfet. In add, i am not sure of the bq soldering couse of the problem i described 2some message ago.

[mcplslg123]

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

Considering your stuggle with even soldering a chip,i'll strongly suggest to take it to some professional. An unproperly soldered chip may take you down to a rabbit hole in diagnosis.

[giulio93]

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

Considering your stuggle with even soldering a chip,i'll strongly suggest to take it to some professional. An unproperly soldered chip may take you down to a rabbit hole in diagnosis.

The problem is the chip. I'm soldering from 10 yeas now and i never had this kind of problem. I see many other people having trouble in soldering in this period, especially with china chips