HP 15-BS588TU No Power ON

[jeewantha]

This Laptop came in no power condition.
When I checked 3v & 5v only come after press power key.
But after few seconds it is going to zero. Then I checked voltages of 3v/5v driver IC. Problem is ENABLE signal is going to after few seconds.
One place of PCB have a Corrosion & I cleaned that place & re-soldered that components. (Image 1)
After it after it all voltages are present without one place.
I don't know that place have voltage or it's value(PCZ 69).(Image 2)
Now board problem is no display.
Anyone can tell what is the voalyage of that place or what I need to check?

MB : CSL50/CSL52 LA-E801P
Rev:2.0
2017-07-18

[mon2]

Re: HP 15-BS588TU No Power ON

hi. see attached.

voltage = 2v5 = 2.5 volts.

capacitance appears to be 390 uF.

The color of the cap denotes this is not a standard cap but one with higher current rating. Difficult to say what is the exact current rating but source one that will fit this SMD pad location and one that is the highest current rating you can buy.

Perhaps others can share their advice.

[jeewantha]

Re: HP 15-BS588TU No Power ON

hi. see attached.

voltage = 2v5 = 2.5 volts.

capacitance appears to be 390 uF.

The color of the cap denotes this is not a standard cap but one with higher current rating. Difficult to say what is the exact current rating but source one that will fit this SMD pad location and one that is the highest current rating you can buy.

Perhaps others can share their advice.

I asked about actual voltage of this point. I mean out put voltage of this buck converter. Not about capacitor.

[mon2]

Re: HP 15-BS588TU No Power ON

Trace the cap and local coil to the mated regulator ic.

Remove this regulator ic. Post the markings on this regulator.

After the removal, post the voltage on each regulator pin.

With the voltage input and feedback resistor voltage divider, it should be possible to calculate the Vout.

Will help if the voltage feedback resistor values are posted.

[piernov]

Re: HP 15-BS588TU No Power ON

https://www.badcaps.net/forum/showpo...02&postcount=2

2.7. Don't apply power to the board with missing components
As a general rule, if a component is on the board, it's because it's useful for something. Engineers don't like adding a bunch of useless components on the board, it's harder to draw the schematics and route on the PCB.
Some of them can be removed without creating problem if power is applied, but others can kill the board with no possibility of repair.
For example, if you remove a buck controller or a MOSFET driver, the MOSFET gates will be floating. They'll charge up enough so that the MOSFET turns on. Of course, you don't want the 19V from the main power rail to go straight through the CPU VCore MOSFET to the CPU.

[jeewantha]

Re: HP 15-BS588TU No Power ON

If remove the regulator IC, gate pin of FET be floating.
As a result of it some time the 19v directly going to output side from the coil.
So I remove coil, two FETs and driver IC.
After it I read voltages.

[jeewantha]

Re: HP 15-BS588TU No Power ON

https://www.badcaps.net/forum/showpo...02&postcount=2

I am not going to inject voltage.
I want to find the reason for no display.
I think missing voltage is the problem.
But I haven't idea, how fix it.

[mon2]

Re: HP 15-BS588TU No Power ON

Can you post a zoomed pic of the related switching regulator? Are the markings "CG9" ?

[jeewantha]

Re: HP 15-BS588TU No Power ON

Can you post a zoomed pic of the related switching regulator? Are the markings "CG9" ?

yes

CG9