HP R33 no +VCC_GFX

[raajkumar]

I checked PU15 (NCP5911) and it has power on
Pin1 - BST - 4.89V
Pin2 - PWM - 1.9V
Pin3 - DRVEN - 4.89V
Pin4 - VCC - 5.1V
Pin5 - Low gate - 0v
Pin6 - GND - 0v
Pin7 - SW - 0v
Pin8 - Hi gate - 0v

Is this OK for this chip?. But i couldn't find any voltage on PL29.

[raajkumar]

Re: HP R33 no +VCC_GFX

I replaced another chip but i got some different results. There are
Pin1 - BST - 0V
Pin2 - PWM - 1.9V
Pin3 - DRVEN - 1.9V
Pin4 - VCC - 5.1V
Pin5 - Low gate - 0v
Pin6 - GND - 0v
Pin7 - SW - 0v
Pin8 - Hi gate - 0v

So which one is correct. This also not produced any voltages on PL29

[piernov]

Re: HP R33 no +VCC_GFX

The new chip isn't soldered properly I think. Anyway what is the resistance between +VIN_VCC_GT and pin 7, and between pin 7 and 6?

[raajkumar]

Re: HP R33 no +VCC_GFX

The new chip isn't soldered properly I think. Anyway what is the resistance between +VIN_VCC_GT and pin 7, and between pin 7 and 6?

+Vin_VCC to Pin7 is 300 Kohms, Pin7 and Pin6 is 200 Ohms

[piernov]

Re: HP R33 no +VCC_GFX

Sounds ok so I would go for a defective/wrongly soldered PU15.

[raajkumar]

Re: HP R33 no +VCC_GFX

Sounds ok so I would go for a defective/wrongly soldered PU15.

I replaced PU15 with another one ( I am getting those from scrap boards ) now again it shows

Pin1 - BST - 4.89V
Pin2 - PWM - 1.9V
Pin3 - DRVEN - 4.89V
Pin4 - VCC - 5.1V
Pin5 - Low gate - 0v
Pin6 - GND - 0v
Pin7 - SW - 0v
Pin8 - Hi gate - 0v

But still i cannot find any voltages on PL29

[piernov]

Re: HP R33 no +VCC_GFX

Do you have an oscilloscope to check the signal on pin 2 — PWM?

[raajkumar]

Re: HP R33 no +VCC_GFX

Do you have an oscilloscope to check the signal on pin 2 — PWM?

I don't have oscilloscope. I checked with 3 chips on PU15.

[piernov]

Re: HP R33 no +VCC_GFX

Maybe the issue comes from PU10 not outputting the right PWM signal. Your issue looks very similar to https://www.badcaps.net/forum/showthread.php?p=754825 even though the board relatively different.

[raajkumar]

Re: HP R33 no +VCC_GFX

Maybe the issue comes from PU10 not outputting the right PWM signal. Your issue looks very similar to https://www.badcaps.net/forum/showthread.php?p=754825 even though the board relatively different.

I have doubt on that also. But unfortunately i have only NCP6131 but on this board need to put NCP6132 it is not same. So have to wait until to get new chip.

[piernov]

Re: HP R33 no +VCC_GFX

Unfortunately no, NCP6131 is QFN-52 and NCP6132 is QFN-60 package.

[raajkumar]

Re: HP R33 no +VCC_GFX

Unfortunately no, NCP6131 is QFN-52 and NCP6132 is QFN-60 package.

Today i replaced PU15 and checked again. The following results came.

Pin1 - BST - 4.89V
Pin2 - PWM - 0V Change found on here
Pin3 - DRVEN - 4.89V
Pin4 - VCC - 5.1V
Pin5 - Low gate - 5v Change found on here
Pin6 - GND - 0v
Pin7 - SW - 0v
Pin8 - Hi gate - 0v

[raajkumar]

Re: HP R33 no +VCC_GFX

I solved this problem by Flashed the bios with new. Now the laptop working fine. Thanks Piernov for your ideas and help.

[piernov]

Re: HP R33 no +VCC_GFX

Could you write the final measurements before and after BIOS flash? It may help others.

[raajkumar]

Re: HP R33 no +VCC_GFX

Could you write the final measurements before and after BIOS flash? It may help others.

Sorry I measured only Hi gate Pin 8. It shows 1.03V and Pin2 ( PWM ) Shows only - 0V. Now i handover the laptop to customer.