HP Probook 4420s won't power up on charger

[sonunigam]

Dear Friends,
I have almost a same problem, but My laptop is turning on by Battery but won't power up by Charger. I checked the circuit, where i analyse that there are no voltages on PQ3 Pin# 4, but Pin1 and Pin3 have voltages.
And please let me know what is +VAPWR and what is +VINVA?
By the way i've changed LM393 PU19 but there is noting happen.
One more thing, there are no VIN Voltages, when i connect the charger. I mean when i check the VIN Voltages on PD2 or BQ24740 Pin# 28. No VIN voltages present. . .
Please help me out. . .
Thanks a lot

[polytek]

Re: HP Probook 4420s won't power up on charger

hi;
check PQ2. PQ3 AND PD1
this is the schematic see page 36 charger;

[sonunigam]

Re: HP Probook 4420s won't power up on charger

I've checked but not successful. . . . any other suggestion????

[shijeesh]

Re: HP Probook 4420s won't power up on charger

Please check PQ3 Source pin and Gate pin voltage

[sonunigam]

Re: HP Probook 4420s won't power up on charger

Dear Shijeesh,
I've checked the voltages on
Source = 19.50V
Gate = 19.09V
Drain = 0.04V
and one more thing there is 3.3 Voltages present on Power Switch. . .
What is this? I'm really messed up. Please help me out please. . . .
Thanks for your reply
bye

[sonunigam]

Re: HP Probook 4420s won't power up on charger

Dear Shijeesh,
I've checked the voltages on
Source = 19.50 V
Gate = 0.04 V
Drain = 19.09 V
Sorry for the above reply. I wrongly typed the volts on Gate and Drain.
Please help me out. . .

[saularciga]

Re: HP Probook 4420s won't power up on charger

Voltages in PU19B? pin 1 and pin 7 have it 3 volts? If are not, NEVER will activate PQ3
+2VREF are generated by TPS51123.
+3VPCU from of OUT of PU9.
VIN of PU9 from +5VPCU

[shijeesh]

Re: HP Probook 4420s won't power up on charger

Pls check voltage on PU2 BQb24740's Pin 28 (PVcc).

[sonunigam]

Re: HP Probook 4420s won't power up on charger

Hello Shijeesh,
No voltages on BQ24740's Pin # 28. . . . (PVcc).

[saularciga]

Re: HP Probook 4420s won't power up on charger

VOLTAGE IN PU9?????
VOLTAGES EN PIN 6 and 6 OF PU8?

[shijeesh]

Re: HP Probook 4420s won't power up on charger

This voltages are correct
Dear Shijeesh,
I've checked the voltages on
Source = 19.50 V
Gate = 0.04 V
Drain = 19.09 V
Sorry for the above reply. I wrongly typed the volts on Gate and Drain.
Please help me out. . .


That means +VAPWR 19V supply is OK, then pls check PQ2.

[sonunigam]

Re: HP Probook 4420s won't power up on charger

No dear,
This is not like that. I was confused about Gate and Drain. But now i'm sure that

Source = 19.51 V
Drain = 0.04 V
Gate = 19.09 V
now these're the voltages. . . .
One more thing when i connect power adapter and press power switch, the PU8 (RT8206B) is going heat up, I changed that PU8 (RT8206B) but same condition. When turning on this motherboard on Battery everything is working fine.
Please help me out. . .

[sonunigam]

Re: HP Probook 4420s won't power up on charger

Hello Saularciga,
I've checked voltages which you mentioned. I've Checked PU9 (RT9043BG) Voltages as below

Pin 1 = 4.95 V
Pin 2 = 0 V
Pin 3 = 3.31 V
Pin 4 = 1.20 V
Pin 5 = 3.39 V

PU 19 (LM393)
Pin 1 = 0 V
Pin 2 = 1.98 V
Pin 3 = 0 V
Pin 4 = 0 V
Pin 5 = 2.25 V
Pin 6 = 1.98 V
Pin 7 = 3.34 V
Pin 8 = 4.95 V

Now tell me what should i do? Please please please help me out. I'm very very very upset.

[saularciga]

Re: HP Probook 4420s won't power up on charger

, Ok, measure the resistence of PR313 and PR226, one of these resistances are open.
At the entrance of the resistance PR313 should be 19.5v . On pin 1 of U19 you should have 3V, If so, make a bridge or a short pin 7 to pin 1.

On pin 3 of U19 should be : (19.5*41200) /200000+41200) = 3.3V. All voltages of U19 are Ok

a test more fast is removing Q13.

Measure the voltages of U18 and PQ2 , in pin 4 should be 5V, this activated PQ6, and this activated PQ2,. Measure PQ2 maybe are damaged

[saularciga]

Re: HP Probook 4420s won't power up on charger

revisa this voltages. Anexo

[sonunigam]

Re: HP Probook 4420s won't power up on charger

Hello Saularciga,
I've tested the resistor PR313 and PR226 and both are fine. The value of those resistors are ok. Now, at the entrance of that resistor PR313. No voltages like 19.5 Volts coz I don't have +VAPWR voltages. and what do you mean that i should make a bridge or short PU19 Pin1 and Pin7?
And please check the diagram there is no Q13 in there.
Can you tell me What should i do? Coz on PQ3's Pin4 no +VAPWR Voltages. . . .

[sonunigam]

Re: HP Probook 4420s won't power up on charger

Hello Saularciga,
Here are some Readings from a HP 4420s Working Motherboard. I thought i should share with you. Maybe it will helpful for me.

When Adapter Plugged in without Battery and without pressing power button:

PQ2 (6679BGH)
Pin 1 = 1.77 V = Gate
Pin 2 = 19.50 V = Drain
Pin 3 = 19.50 V = Sorce

PQ3 (6679BGH)
Pin 1 = 7.84 V = Gate
Pin 2 = 19.50 V = Drain
Pin 3 = 19.50 V = Source

PU19 (LM393)
Pin 1 = 3.28 V = 1OUT
Pin 2 = 1.98 V = 1IN-
Pin 3 = 3.31 V = 1IN+
Pin 4 = 0 V = GND
Pin 5 = 2.25 V = 2IN+
Pin 6 = 1.98 V = 2IN-
Pin 7 = 3.24 V = 2OUT
Pin 8 = 5.04 V = Vcc

PU9 (RT 9043BG)
Pin 1 = 5.05 V = VIN
Pin 2 = 0 V = GND
Pin 3 = 3.38 V = EN
Pin 4 = 1.24 V = FB
Pin 5 = 3.29 V = VOUT

PU24 (LMV321)
Pin 1 = 1.23 V = 1IN+
Pin 2 = 0 V = GND
Pin 3 = 1.19 V = 1IN-
Pin 4 = 5.05 V = OUT
Pin 5 = 5.05 V = Vcc

PU18 (G1331) PV Modified with LM321
Pin 1 = 3.75 V = 1IN+
Pin 2 = 0 V = GND
Pin 3 = 0 V but When press power button going towards 0.15 V = 1IN-
Pin 4 = 5.03 V = OUT
Pin 5 = 4.88 V = Vcc

Now these are all voltages on a working motherboard. Now can you help me out????
What is the faulty part in it?

[saularciga]

Re: HP Probook 4420s won't power up on charger

Remove PQ3, and shorted pin Drain and Source.
Before measure Gate of PQ11.
WHAT TYPE IF PQ3 IS? NUMBER FULL PLIS

[saularciga]

Re: HP Probook 4420s won't power up on charger

This is pinout of PQ3 and this it´s datasheet

[whaldsz]

Re: HP Probook 4420s won't power up on charger

1. Also confirm these resistance values, PR6 =220k, PR123 = 150K. Probably PR6 is open that is why you are getting 0.04v at the gate of PQ3.
2. Could you measure the resistance across PC3?
3. Voltage at pin PQ9 and PQ11? You must have these voltages for normal operation.