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Old 03-25-2020, 12:17 PM   #1
Weelcup
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Default Hp omen 15-DC. 3.3v ALWS only 1.36v !!! 5v present!

Hi friends
I have omen 15-DC motherboard. 3.3V power rail only gives 1.36V !?

5V is present.

I replaced the 3.3V provider IC but same issue.
3.2v present on power button.

I also replaced super io chip but same!!
.

Any suggestion?
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Old 03-25-2020, 12:40 PM   #2
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Default Re: Hp omen 15-DC. 3.3v ALWS only 1.36v !!! 5v present!

Remove one Pad of coil 3ALWS and check the Voltage again, check the resistance to ground out put side of 3V line, Upload the Schematic or MB ID ?
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Old 03-25-2020, 01:40 PM   #3
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Default Re: Hp omen 15-DC. 3.3v ALWS only 1.36v !!! 5v present!

Quote:
Originally Posted by techtiger View Post
Remove one Pad of coil 3ALWS and check the Voltage again, check the resistance to ground out put side of 3V line, Upload the Schematic or MB ID ?
Thanks for following up,
When rermoving one side of the 3.3v rail. There is 18.6V on the IC side of the rail.

Unfortunately, there is no schematic available for this motherboard.

The motherboard id is, DA0G3DMBCE0 Rev E.
The 3.3V ic is RT6256B.
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Old 03-26-2020, 01:45 AM   #4
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Default Re: Hp omen 15-DC. 3.3v ALWS only 1.36v !!! 5v present!

r u sure u measure it right?

19V on that rail will butn RT ic and all 3,3V components
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Old 03-26-2020, 12:21 PM   #5
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Default Re: Hp omen 15-DC. 3.3v ALWS only 1.36v !!! 5v present!

Quote:
Originally Posted by ktmmotocross View Post
r u sure u measure it right?

19V on that rail will butn RT ic and all 3,3V components
Well, it is strange to me too. Remember, when i connect both sides of the rail it produce only 1.36v. But if i disconnect one of the rail sides, the ic side becomes 18v. I mean the rail side that gets the volt. From the ic.

Last edited by Weelcup; 03-26-2020 at 12:22 PM..
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Old 03-27-2020, 11:34 PM   #6
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Default Re: Hp omen 15-DC. 3.3v ALWS only 1.36v !!! 5v present!

rail dont get volt from chip but from step down circuit . u can have shorted high side mosfet, but that means all components on 3,3V si must be burnt
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Old 03-28-2020, 11:01 AM   #7
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Default Re: Hp omen 15-DC. 3.3v ALWS only 1.36v !!! 5v present!

Quote:
Originally Posted by ktmmotocross View Post
rail dont get volt from chip but from step down circuit . u can have shorted high side mosfet, but that means all components on 3,3V si must be burnt
Maybe, but i have checked all mosfets. Non is shorted to ground!. Besides 19v is present. 5.1v is present. Only 3.3v is missing.

I suspect the pch. Hoever, it is not shorted. I also suspect the graphic chip but not shorted as well. Soooo confusing.
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Old 03-28-2020, 11:24 AM   #8
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Default Re: Hp omen 15-DC. 3.3v ALWS only 1.36v !!! 5v present!

On what pin do you have 5.1V present .The RT6256B and C have a different pinout
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Old 03-28-2020, 11:27 AM   #9
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Default Re: Hp omen 15-DC. 3.3v ALWS only 1.36v !!! 5v present!

Quote:
Originally Posted by SMDFlea View Post
On what pin do you have 5.1V present .The RT6256B and C have a different pinout
Sorry for the confusion, i was taking about the rt6256C output not B. Just to clarify that 5v is present in the abscense of 3.3v...
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Old 03-28-2020, 11:43 AM   #10
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Default Re: Hp omen 15-DC. 3.3v ALWS only 1.36v !!! 5v present!

Ok start again then, post voltage for all pins and resistance to gnd .

https://www.richtek.com/assets/produ...S6256BC-02.pdf

Last edited by SMDFlea; 03-28-2020 at 11:44 AM..
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Old 03-30-2020, 11:15 AM   #11
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Default Re: Hp omen 15-DC. 3.3v ALWS only 1.36v !!! 5v present!

Quote:
Originally Posted by SMDFlea View Post
Ok start again then, post voltage for all pins and resistance to gnd .

https://www.richtek.com/assets/produ...S6256BC-02.pdf
Thanks for following up. Actually i managed to find the issue.

It turned out that the charger was issue. Everthing seems to work fine after replacing the charger. Although the old charger was tested and everything thing was ok with the charger even the voltage on the middle pin was there. But it was generic180w charger.

This laptop only works with hp original charger as there were no way to get it to pass the 3.3v correctly with the generic charger. Very weired !! But this is the solution.

Thanks for everyone who advised and helped me ..

Kind regards

Last edited by Weelcup; 03-30-2020 at 11:16 AM..
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