hp 8460p schematic please guys

[Blacktek]

anybody has this model? it has to be VERSION 2, Please guys

[Th3_uN1Qu3]

Re: hp 8460p schematic please guys

Is it this one?

[Blacktek]

Re: hp 8460p schematic please guys

thanks a lot buddy, but this is v.A01. completely different

[Blacktek]

Re: hp 8460p schematic please guys

ok so heres the problem with this laptop, maybe someone can give me some pointers:
Laptop wont turn on at all, it shorts the adapter and it makes noises when you plug it into the jack. there this mosfet 331bqbd that gets really hot while plugged in, but i replaced and still the same thing.
If the mosfet is removed the issue goes away. But since i dont have the schematic its hard to trace it. the motherboard model is 6050A2398501-A02.
The mosfet in question is Q514.

[BCConnectionLLC]

Re: hp 8460p schematic please guys

ok so heres the problem with this laptop, maybe someone can give me some pointers:
Laptop wont turn on at all, it shorts the adapter and it makes noises when you plug it into the jack. there this mosfet 331bqbd that gets really hot while plugged in, but i replaced and still the same thing.
If the mosfet is removed the issue goes away. But since i dont have the schematic its hard to trace it. the motherboard model is 6050A2398501-A02.
The mosfet in question is Q514.

Have you metered on either side of the mosfet when removed for a short?

Diode/Beep Mode on a meter. Red probe on GND. Black probe on the points.

Find the short and inject a voltage on that rail at the same rated voltage. Use a power supply or bench top supply. This should make whatever is shorting it out HOT or blow it up.

[atsio]

Re: hp 8460p schematic please guys

Have you metered on either side of the mosfet when removed for a short?

Diode/Beep Mode on a meter. Red probe on GND. Black probe on the points.

Find the short and inject a voltage on that rail at the same rated voltage. Use a power supply or bench top supply. This should make whatever is shorting it out HOT or blow it up.

And if he needs to supply i.e. 19v and the fault is a fet and this 19v end up to a chipset or even CPU, then what?

[dj_ricoh]

Re: hp 8460p schematic please guys

And if he needs to supply i.e. 19v and the fault is a fet and this 19v end up to a chipset or even CPU, then what?

if the 19v line its shorted then it will short the adapter.

there are 2 cases in the forum with upper fets for cpu where bad and they turn off the adapter.

i think in this case its not the problem or not similar.

[atsio]

Re: hp 8460p schematic please guys

What I am saying is that you do not inject hi voltage (without controlling amps) to a board to check for shorts. You just inject slowly amps and 0,5 amp in most case is more than enough to show you what is getting hot.

[BCConnectionLLC]

Re: hp 8460p schematic please guys

Shorted CPUs must be a common thing for you because it seems to be your suggestion every time.

Although if you think injecting 19V on a 19V rail will blow up the CPU then I guess the CPU needs a better regulatory circuit on boards you work on. Its not like the main Power rail just feeds 19V to the CPU.

I do this because my power supply wont shut off because of a short. Unlike the adapter which protects itself.

[atsio]

Re: hp 8460p schematic please guys

I assume you end up with a lot of blown up boards

[Blacktek]

Re: hp 8460p schematic please guys

play nice kids! thank you guys i have a bad fet at the end of powerjack rail. i'll replace it and keep you guys posted

[Blacktek]

Re: hp 8460p schematic please guys

ok guys replaced it, and saw how beautiful caps blow, and tell you where problem is.. ..
It was shorted to ground at isl95831 at couple pins, once cap was replaced no short.
no i just have to test it but i have to find a processor first.

[BCConnectionLLC]

Re: hp 8460p schematic please guys

I assume you end up with a lot of blown up boards

Not a single blown up CPU yet. Crazy how buck converters and voltage sense systems work arent they?

[atsio]

Re: hp 8460p schematic please guys

I think I am not the only one saying this (from Elvikom's training thread)

"
There are two main points to notice when performing a short-test:
1. In case when heat can be felt on the core of either of the bridges or graphics card, short-test should be immediately stopped. In this cases usually one of the transistors working with the DC controller is shorted and there is a risk of connecting high e.g. 19V voltage directly to the bridge or graphics card which are usually powered by 1V to 5V voltage. In this case you can't tune up the voltage above value, which is normally operated in lower values (for example, for the 1,8V power rail you can tune up the voltage only to 1,8V value maximum!).
"
https://www.elvikom.pl/szkolenie-nr-...opow-t986.html

[BCConnectionLLC]

Re: hp 8460p schematic please guys

Where did I say inject 19V on a 1v or 5v rail?
I said inject 19v on the 19v main power rail that normally sees 19V...

If there was a short directly from 19V rail to the CPU then its already done its damage before you ever start testing.

[atsio]

Re: hp 8460p schematic please guys

Where did I say inject 19V on a 1v or 5v rail?
I said inject 19v on the 19v main power rail that normally sees 19V...

If there was a short directly from 19V rail to the CPU then its already done its damage before you ever start testing.

You still do not get it. Usually the drain of upper fets on voltage regulators is on the 19v rail. If the fet is open and you inject 19v on the 19v rail, 19volts end up on the source rail of the fet (whatever volt is that).

[BCConnectionLLC]

Re: hp 8460p schematic please guys

You still do not get it. Usually the drain of upper fets on voltage regulators is on the 19v rail. If the fet is open and you inject 19v on the 19v rail, 19volts end up on the source rail of the fet (whatever volt is that).

So to avoid this then you check the CPU voltage rail for a short or continuity through the FET. If its closed feed voltage. Also if the FET was already sending through 19v to the cpu to cause the short issue then the CPU is already done for. 19v at full amp draw on a 1.8V ine is going to destroy anything on the line quickly.

[atsio]

Re: hp 8460p schematic please guys

You forget protection (found in most designs). 19 volt never reach this place when you are plugin the adapter.

[meritosari]

Re: hp 8460p schematic please guys

You still do not get it. Usually the drain of upper fets on voltage regulators is on the 19v rail. If the fet is open and you inject 19v on the 19v rail, 19volts end up on the source rail of the fet (whatever volt is that).

do you mean like this? (see attachment)

Well done.
Also that is why I sometimes say to not apply more than 1v test when finding a short. There might be a shorted High Side MOSFET sending the test voltage directly to CPU, NB or GPU.

its nice you share what you got from your knowledge

[atsio]

Re: hp 8460p schematic please guys

do you mean like this? (see attachment)

Yes, and even more dangerous having a half dead fet and testing it looks fine but when you apply high current-voltage dies completely.