Dell Latitude 3330 shuts-down

[usyusy]

Dell Latitude 3330 (DLA13 MB 12275-1 WB: 8G44H REV:AOO), shuts-down mostly when windows load, however remains on when entered in bios page. When powered-off, it did not power-on until we removed the charger and again power-on. Any guidance please.

(charger, Ram, and HDD were also replaced but same result)

Some readings:

Charger connector : 19.9V
1st Mos (p channel) : D & S = 19.9V, G=4.7V
2nd Mos (p channel) : D & S = 19.9V, G 1.7V

CLR : 19.9V both sides

[usyusy]

Re: Dell Latitude 3330 shuts-down

Pu4801 SY8037DDCC_VCCSA getting hot and its coil pl4801 giving .006 impedence to ground and giving beep
Lifiting 1 leg, output side showing beep

[mcplslg123]

Re: Dell Latitude 3330 shuts-down

Pu4801 SY8037DDCC_VCCSA getting hot and its coil pl4801 giving .006 impedence to ground and giving beep
Lifiting 1 leg, output side showing beep

Give resistance in Ohms?? This rail will show low resistance.

[usyusy]

Re: Dell Latitude 3330 shuts-down

Give resistance in Ohms?? This rail will show low resistance.

ok sir, but this VCCSA IC getting much hot, even 100°C, and its input +5V_ALW(pin 10,11,12) line seems to be short as 5v coil giving beep/no voltage (3v ok), Also its pin 8 (VOUT), pin 1, 2 & 3 (LX#1,2,3 i.e +VCC_SA) giving beep.

(the 5v section seems to be ok as i lift 1 leg of 5v Coil and no input side but output side shortage was showing)

so what should i do now. is soc short/gone or further testing can be done.

[mcplslg123]

Re: Dell Latitude 3330 shuts-down

Beep..beep and beep. Thats 'coz you are measuring in diode mode. Low voltage/high current rail should'nt be measured in diode mode as meter will always beep and make you confused.

Measure exact resistance in Ohms mode on VCCSA coil & 5VALW Coil. Then proceed to remove VCCSA IC, and recheck Resistance on both these coils.

Give us those measurements. Motherboard is at your desk,so we do need measurements.

[usyusy]

Re: Dell Latitude 3330 shuts-down

You are right sir, I was really confused and not know what was the issue.
The measurements on 2k setting:
Before removing vccsa ic;

Vccsa coil (Pl4801) 0.005
5v coil (Pl4101) 0.011

After removing vccsa ic :

Vccsa coil (Pl4801) 0.005 same
However
Red prob on ground
5v coil (Pl4101) 0.090
While
Black on ground
5v coil (Pl4101) 0.369

[mcplslg123]

Re: Dell Latitude 3330 shuts-down

Measure VCCSA coil with 200 Ohms setting. 5V coil should be measured with atlest 200K settings.

VCCSA resistance is 5 Ohms and that may be fine.

5V coil resistance is still too low. Remove the 5V coil and measure resistance with 200K or higher settings on both pads of this coil. If input side shows low resistance, then 5V regulator ic is bad. However, most likely low resistance will be on output side and you need to inject voltage to find out what is defective.

[usyusy]

Re: Dell Latitude 3330 shuts-down

On 200 ohm settings:

Vccsa coil : 6.4 ohm

On 200k settings:

After removing 5v coil:

Input side of coil : 42.5
Output side of coil: 0.3

So output side seems to be short as you said, so how much voltage should be input at this side
My dc supply is 30v, 3A

[mcplslg123]

Re: Dell Latitude 3330 shuts-down

Start with 1V/1A and gradually go up. You can iject a maximum of 5V on this line but has to make sure that no high side mosfet is shorted.

However, your dc supply is not very suitable for repair job. You should invest in a 30V/10A dc supply or atlest 30V/5A dc supply. With your existing dc supply a lot many gaming boards will behave strangely during power up.

[usyusy]

Re: Dell Latitude 3330 shuts-down

Injecting 5.2v, 3a on the output side of 5v coil,
Only 3v/5v ic ( PU410) seems to be getting hot, (about 46 degree centigrade)
Before injecting voltage, 5v coil was removed.

[mcplslg123]

Re: Dell Latitude 3330 shuts-down

Remove the IC and recheck resistance on 5V coil.

[usyusy]

Re: Dell Latitude 3330 shuts-down

I removed the ic, but resistance on 5v coil is same

[mcplslg123]

Re: Dell Latitude 3330 shuts-down

Inject voltage on the shorted side and leave it this way for 10-15 mins and then see if you can feel any area of the mb hot. With your dc supply, it will be very mildly hot,so you just need to identify the probable area of mb and then finally findout the faulty component on that area.

[usyusy]

Re: Dell Latitude 3330 shuts-down

vccsa ic was getting hot, removed.
3v5v ic hot, then tried to cut off its 5V_PWR, so
5v coil removed,
PR4115 removed
PD4101 removed
PD4103 removed, still 3v5v ic hot, from where its getting voltage, not know