HP 8440P strange problem

[sonunigam]

Hello all guys,
I'm checking an Elitebook 8440P which is not turning on but the charging light blinking with blue and orange when i connect the charger.
I thought that it is the problem bad controller so i replaced with new one KBC1098NU. But same, So i changed TPS 51125 and BQ 24740 but all is vain.
When i closely look the voltages on PQ101 Pin Numbers 5,6,7,8 and there are no voltages. But on a working Motherboard there are 19 Volts here. Again when i check PQ 101 Pin # 4, There are 19 Volts but when i check on a working Motherboard there are 8.65 Volts.
Anybody can tell me what should i do?

[sonunigam]

Re: HP 8440P strange problem

Hey all,
There's nobody who can tell me what is the fault? or guide me how to check the problem?
Amazing! Is this a forum for Professionals?????

[dj_ricoh]

Re: HP 8440P strange problem

Hey all,
There's nobody who can tell me what is the fault? or guide me how to check the problem?
Amazing! Is this a forum for Professionals?????

YES! this is for PRO!
you know why i know that?

1. all the pro techs they got a life you know? SUNDAY!
2. they all got jobs(some of them related with the theme of the website.
3. PRO techs don`t bother to reply when you ask for help like that!

and where are the photos of the board? full model mobo and where is the schematic you print screen it?

[sonunigam]

Re: HP 8440P strange problem

Okay dear, Thanks for correction. Now, i'm gonna send you the schematic diagram. . .
This is HP Elitebook 8440P.

[sonunigam]

Re: HP 8440P strange problem

Hey all,
Any professional have some moments for me. . . I'm stuck in HP 8440P, Please help me out. . . . Pleaseeeeeeeeeeeeeeeeeeeeeeeeee

[dj_ricoh]

Re: HP 8440P strange problem

Take out pc101 and pr101 and test them.
One of them is shorted or leaking. Thats why you got 19v.

You can take them out connect charger and inject voltage on pin 4 with 8v like you got on working motherboard

[sonunigam]

Re: HP 8440P strange problem

I already checked PC101 and PR101, I checked them with multi-meter. PR101 shows 199.4 Kohms and with capacitor or without capacitor same situation. No change. . .

[dj_ricoh]

Re: HP 8440P strange problem

pr111 its ok?

[sonunigam]

Re: HP 8440P strange problem

Yes dear,
This is okay. . .

[dj_ricoh]

Re: HP 8440P strange problem

Take that pq101 and do a diode test on it.

After find out where that 19v its coming.

You got a resitor pr101 and a cap pc101 coming from adapter
And a resistor from KBC pr111
Eder way you got 4 options here 2 resistors one cap or the fet internal shot and leaking to gate.

[Speedzion]

Re: HP 8440P strange problem

Thanks dear

[ktmmotocross]

Re: HP 8440P strange problem

on gate of first mosfet u must have lover voltages than 19V because it is P-channel mosfet. ADP_EN# must be grounded to have that lower woltage so both gates of PQ1007 must have positive signals

u cannot see that easy thing?