HP ProBook 4510s power problem

[rtstorm]

Hello, i have HP 4510s with power issue. No LED, nothing. I try to reflesh BIOS no help.

I check voltages on DC jack and thy are ok.

I find that voltage do not go further than Q25. I have 19v on pin 1,2,3,4 but 5,6,7,8 are 0V.

Is this MOSFET bad?

[meritosari]

Re: HP ProBook 4510s power problem

i think :
- p-channel mosfet only work if negative voltage on pin #4
- u1004 is ic comparator to drive adp_en# come out to give negative voltage than 19v ( around 7-9v)

[rtstorm]

Re: HP ProBook 4510s power problem

i check U1004
pin1 - 0V
pin2 - 6V
pin3 - 0V
pin4 - 0V
pin5 - 5V
pin6 - 0V
pin7 - 19V
pin8 - 19V

[meritosari]

Re: HP ProBook 4510s power problem

i think ic comparator act as system protection, on schematic looks too complicated.
pin#5 must be high than pin#6 was ok, but pin#3 should be high than pin#2.
do you use original hp adapter?
what about q25? try measure resistance on all pin respect to ground.
and measure D-S, S-D on q25 (off course without adapter and battery)

[rtstorm]

Re: HP ProBook 4510s power problem

I use original HP adapter (i have 2 of them).

G - gnd = 240 kOhm
S - gnd = 15.5 kOhm
D - gnd = 12 kOhm


D - S = 5.2k kOhm
S - D = 28.8 kOhm

[meritosari]

Re: HP ProBook 4510s power problem

I use original HP adapter (i have 2 of them).

G - gnd = 240 kOhm
S - gnd = 15.5 kOhm
D - gnd = 12 kOhm


D - S = 5.2k kOhm
S - D = 28.8 kOhm

look like still good. did you check another p-channel mosfet? q26, q17 and q13
measure respect to ground and crossong on those mosfet

[rtstorm]

Re: HP ProBook 4510s power problem

i check them, thy are ok.

I found that Q1030 has 18 ohm D-S resistance. And coil L1020 has 18 ohm respect to ground

[meritosari]

Re: HP ProBook 4510s power problem

i check them, thy are ok.

I found that Q1030 has 18 ohm D-S resistance. And coil L1020 has 18 ohm respect to ground

i don't have any word to explain about high impedance. usually on this rail was low resistance. and i think wasn't short. same as cpu still installed, and you measure on that rail you must got low resistance, but after you removed cpu, resistance got high

i don't have experience with hp that have a lot protection like this.

but, wait. i think i miss a thing.
why pin#7 u1004 is 19v, should be lower than 19v. so check R28, R68, R1004

[rtstorm]

Re: HP ProBook 4510s power problem

When i remove CPU i have 21 ohm on Q1030.

I cannot find R28, R68 and R1004 but i measure resistance from D1002 pin #2 to GND and i have 92.7 koHm.

[samanthban]

Re: HP ProBook 4510s power problem

I think q 1018 is short..

[rtstorm]

Re: HP ProBook 4510s power problem

i check Q1018 and it is not shorted. Diode test OK

[meritosari]

Re: HP ProBook 4510s power problem

i think ic comparator act as system protection, on schematic looks too complicated.
pin#5 must be high than pin#6 was ok, but pin#3 should be high than pin#2.
do you use original hp adapter?
what about q25? try measure resistance on all pin respect to ground.
and measure D-S, S-D on q25 (off course without adapter and battery)

I've got wrong analyze at post#3
pin#3 high if there are charging process, i think it was ok.

see attachment to find Resistor what i mean.
use continuity for trace connection with Q1005(pin#1), D1002, and LM393 pin#7

if short the R that we suspect, it make a sense there is 19v on that pin#4 q25..
maybe other expert correct me if i got wrong about this

link picture HD quality that i use for reference :
http://rusfolder.com/39487276

sorry for my bad english

[HarryPK]

Re: HP ProBook 4510s power problem

[rtstorm]

Re: HP ProBook 4510s power problem

i think i found one of those 2 resistor. I desolder it from board and it is 220 kOhm.

[rtstorm]

Re: HP ProBook 4510s power problem

it is R1004

[meritosari]

Re: HP ProBook 4510s power problem

one leg connnect to pin#1 mosfet and the other connect to ground, right?
if 220k is good. what about rest of 2 resistor that i told you in other side mobo

[rtstorm]

Re: HP ProBook 4510s power problem

non of them are connected to pin#1 of Q1005. I found one that is connected to pin#1 of Q1005 and it is 220k Ohm when i measure it desoldered from board.

[meritosari]

Re: HP ProBook 4510s power problem

nothing progress.... we have to find boardview to find component without mark

[meritosari]

Re: HP ProBook 4510s power problem

http://www.qdzbwx.com/forum.php?mod=viewthread&tid=366

not have point to download it

[rtstorm]

Re: HP ProBook 4510s power problem

yes they all ask for payment. Anyone have point to download pleae?