Pls help. don't get the chance to meassure....

[hansie55]

Hi,
When I switch the laptop on, the led's light up for a brief moment and everything is out again. The battery charges and that led lights up after a few seconds.
I don't get the chance to meassure anything and don't know where to start.
Can somebody pls advise how to attack this problem?

Dell Vostro 3360
mobo: DA0V07MBAD1

[khaahk]

Re: Pls help. don't get the chance to meassure....

Measure resistances on big coils.

[hansie55]

Re: Pls help. don't get the chance to meassure....

Thanks for the reply.

PL1=2,1 PL5=2,0 PL9=2,1
PL2=3,2 PL6=1,8
PL3=2,8 PL7=0,8
PL4=2,6 PL8=0,8

[dellxps15]

Re: Pls help. don't get the chance to meassure....

for me could be chipset that need to be reballed. (not reflown)

does fan spin ?

if it doesnt spin could be also a cpu voltage problem.

[hansie55]

Re: Pls help. don't get the chance to meassure....

Reball is not possible.

Fan does not spin
Where do I look for cpu voltages?

[khaahk]

Re: Pls help. don't get the chance to meassure....

Measure resistances relative to ground, not across coils.

[hansie55]

Re: Pls help. don't get the chance to meassure....

Sorry.

PL1=400
PL2=12,5
PL3=3,1
PL4=12,2
PL5=45k
PL6=92
PL7=1,8
PL8=490
PL9=1,5M

[khaahk]

Re: Pls help. don't get the chance to meassure....

PL3 and PL7 seem low, what are they powering? If you have schematic then post it.

[hansie55]

Re: Pls help. don't get the chance to meassure....

Both 0.0V

something bad just happened. While measuring the V from PU7, I accidentally touched PC136 (gnd side) while measuring pin 10 (little smoke signal)
All the pins were giving a reading, now not anymore.for example, pin 7 was 3,3v is now 1,4v so I think I have to replace PU7 first?

[khaahk]

Re: Pls help. don't get the chance to meassure....

Probably yes, you'll have to change PU7.
Remove cpu and remeasure PL3 and PL7 resistance.

[hansie55]

Re: Pls help. don't get the chance to meassure....

Sorry for the late reply. I'm still fighting to replace PU7. I got it off OK, but I can't get it in place and now my solder-station break so I have to order that first.
Let you know when things pick up again.

[highpulse]

Re: Pls help. don't get the chance to meassure....

hi there , you wont have voltages on coil , only after s5 , the only coils you might have power and the ones for the main reg and the bat coil .

first things you must measure , chek on off button , if you got 3.3 volts and if it drop to 0 once you press the button , if you got no voltage , chek the KBC pin first to see if you got or not the 3.3 volts , if not than you must chek main regulator , chek if you got correct LDO and EN pins .

cheking the values you mentioned on the coil to the GND there is none showing short , and possible the LOW ohm are the coils for the cpu .. it the cpu is one of does that you can remove frmo board , remove cpu and read coils again you must have a bigger value without cpu .

pu7 is dead now , but DONT TURN IT ON WITHOUT PU7 or else you will burn a few mosfets , and might kill some outher parts .. so if you want to make test to the board without PU7 , remove the mosfet associated to that IC .
once you remove PU7 and the mosfet , for that IC chek COILS to GND first , before adding a new PU7 , to make sure you dont have anything damaged on that line /lines .

if all good of what i mentioned , start for cheking S3 states . common signal on KBC .
also once you turn it on , chek usually on the main QFN if you got PGood signal received , if not , then its time for a KBC chek , chek all VCC and all S3 S5 pins , specially make sure RSMRST , workes fine , once you press the on off button , it its not working properly then KBC will order to shutdown machine .

make measurements before adding new components hansie , and let us know

[hansie55]

Re: Pls help. don't get the chance to meassure....

Thx Highpulse.
So I have to try to measure without the P7 ? (after removing mosfets).
The CPU can not be removed on this laptop.

[highpulse]

Re: Pls help. don't get the chance to meassure....

removing ONLY the mosfet that are drived from PU7 , after removing pu7 chek the coils
, so if cpu cannot be removed , i know you cannot reball so therefore also you cannot lift it .but for the values you give , doesn't seem cpu issue . but make the test i told you before going further with this

[hansie55]

Re: Pls help. don't get the chance to meassure....

Thx Highpulse.
Something I have to explain. I'm a senior on a amature level with years of experience in computer spare part business. I do have electronic training but I can't class with you guys at all. So I apologize for misconceptions on my behave.
I will follow your leads to the best I can but somethings might be to difficult. Like removing the 4 mosfets belonging to PU7. This is very hard for me, because I have Parkinson Illness and smd is very tiny. I have broken a couple of motherboards in the past already trying to replace chips. Parkinson and smd are no friends. Therefor it will be better for me to place a PU7 as that is difficult enough without damaging the rest.
It is not because I want to know better, but just because I can't.

[highpulse]

Re: Pls help. don't get the chance to meassure....

yeah i totally understand , and i respect you for that , you can be hill , but your fighting to keep live rooling , and that the spirit we are here to help

[dj_ricoh]

Re: Pls help. don't get the chance to meassure....

Hansie55 you need to make some jigs on hot air and that will be your best friend.

jig for hot air element and it needs to be a little tall so you can put a pre-heater under it.

i`m making one now and next month i`m buying a pre-heater.

and when it comes to QFN soldering yes you need hot air and soldering iron to finish the solder on the side.

[hansie55]

Re: Pls help. don't get the chance to meassure....

Thx Guys,
I will buy a hot air unit end of this month. I tried with a hot-air gun (for paint),but that can not be controlled and you loose a lot of tracks on the mobo.
When I have it, I will consult you for the use.
thx for understanding

[dj_ricoh]

Re: Pls help. don't get the chance to meassure....

Thx Guys,
I will buy a hot air unit end of this month. I tried with a hot-air gun (for paint),but that can not be controlled and you loose a lot of tracks on the mobo.
When I have it, I will consult you for the use.
thx for understanding

yes!

so if the hot air station got level from 1-8 on air level; on the mobo you use max 2 and MAX 400c (380c )

[ktmmotocross]

Re: Pls help. don't get the chance to meassure....

Thx Guys,
I will buy a hot air unit end of this month. I tried with a hot-air gun (for paint),but that can not be controlled and you loose a lot of tracks on the mobo.
When I have it, I will consult you for the use.
thx for understanding

u can use pwm regulator to put down temp an air velocity on that paint gun.