HP 6735B dead, no power

[rtstorm]

hello, i have this laptop with no sign of life. I find that 19V wont pass Q500 mosfet. I have 19V on pin 1,2,3 and 4 and 0V on 5,6,7,8.

It is a P-channel mosfet so the gate need to be lower. I check ADP_EN# a it lead me to U17 (AS393MTR_E1)

U17 have:

pin1 - 0V
pin2 - 6V
pin3 - 0V
pin4 - 0V
pin5 - 5V
pin6 - 0V
pin7 - 19.9V
pin8 - 19.9V

[rtstorm]

Re: HP 6735B dead, no power

please tell me what 'LIMITsignal' stand for on DC jack?

[khaahk]

Re: HP 6735B dead, no power

It must be around 7V from adapter - do you have original working adapter? The other way is to use 350k resistor from 19v to limit signal, it should provide also about 7V to the pin. Otherwise mainboard will not detect adapter present.

[rtstorm]

Re: HP 6735B dead, no power

ok i put 350k between DC in (19V) and Signal limit and laptop worked. Should i leave that? Is this DC jack have 350k build in so the connection broke?

[khaahk]

Re: HP 6735B dead, no power

Most likely the power adapter does not work. (or the center pin is disconnected).

[gcomputers]

Re: HP 6735B dead, no power

ok i put 350k between DC in (19V) and Signal limit and laptop worked. Should i leave that? Is this DC jack have 350k build in so the connection broke?

please can you share any pic?

[rtstorm]

Re: HP 6735B dead, no power

Here is the pic of DC jack from both side.

[rtstorm]

Re: HP 6735B dead, no power

what voltage should i have on center pin (needle) of charger? I have 0V on that needle

[rtstorm]

Re: HP 6735B dead, no power

when i use non HP charger (universal) laptop is working.

[khaahk]

Re: HP 6735B dead, no power

When adapter not connected - approx 19V
When connected - 7-7.5V
The center pin's wire is most likely broken.