HP Pavilion x360 14m-dh0000 no power

[arber1232]

hello, how are you, I hope you are well. I have a laptop HP Pavilion x360 14m-dh0000 ( FAROE_DIS_X32_MB_MV 18742-1 )
The laptop does not turn on and the dc jack has no light
The 19v voltages at the input are fine, there are no shorts.. It shows that the 3.3v voltage is missing. I am also posting the thread if anyone can help me, thank you very much

This is shcematic [MOD EDIT] LINK to schematic --> https://www.badcaps.net/forum/troubl..._mb_mv-18742-1

[arber1232]

Re: HP Pavilion x360 14m-dh0000 no power

PU4501 in pin2345 i have 19v , pin 1 is 0v
pin11 0v
pin12 ov

[mcplslg123]

Re: HP Pavilion x360 14m-dh0000 no power

Resistance and voltage on pin17 of PU4501?? If you dont have dc jack light,very likely 3V LDO is absent and may be shorted.

[arber1232]

Re: HP Pavilion x360 14m-dh0000 no power

Resistance and voltage on pin17 of PU4501?? If you dont have dc jack light,very likely 3V LDO is absent and may be shorted.

Resistance is 340 ohm . voltage is ov

[mon2]

Re: HP Pavilion x360 14m-dh0000 no power

That is considered to be a low resistance for a power rail.

Remove the resistor at R4503 and then check the resistance to ground again of pin #17 of PU4501.

Do you have an adjustable power supply? For 1 volt use.

[arber1232]

Re: HP Pavilion x360 14m-dh0000 no power

That is considered to be a low resistance for a power rail.

Remove the resistor at R4503 and then check the resistance to ground again of pin #17 of PU4501.

Do you have an adjustable power supply? For 1 volt use.

resistance change after remove resistor R4503 now is 1,1mohm
yes is have how can i do

[mon2]

Re: HP Pavilion x360 14m-dh0000 no power

Can you confirm?

The high resistance is on R4503, pin # 1 = same as pin 17 pin or on pin #2 of the removed R4503?

Which side has the low resistance of ~ 300 ohms?

[arber1232]

Re: HP Pavilion x360 14m-dh0000 no power

Can you confirm?

The high resistance is on R4503, pin # 1 = same as pin 17 pin or on pin #2 of the removed R4503?

Which side has the low resistance of ~ 300 ohms?

i put resistor now i have 0.8 k ohm
if i remove resistor i have 3,3 volt in pin 17

[mon2]

Re: HP Pavilion x360 14m-dh0000 no power

Need more details. You have soldered back the 0 ohm resistor @ R4503? Now the resistance to ground is 0k8 = ~800 ohms on pin #17 of PU4501 ?

[arber1232]

Re: HP Pavilion x360 14m-dh0000 no power

Need more details. You have soldered back the 0 ohm resistor @ R4503? Now the resistance to ground is 0k8 = ~800 ohms on pin #17 of PU4501 ?

with resistor pin 17 i have 0.8 k oms without resistor in pin 17 i have 1,1 m ohms and other side resistor with conect with caps pc4507 i have 0.8 ohms ...pin 17 without resistor i have 3,3 volt

[mon2]

Re: HP Pavilion x360 14m-dh0000 no power

Remove all power. Configure your adjustable power supply to 1 volt (NOT higher) and 2A-5A current.

Apply the red probe of your power supply onto the side with the low resistance; black power supply lead to ground.

Search for any part that may be heating up. You are effectively hunting for the shorted part with heat patterns. You can pour IPA (alcohol) and watch which part evaporates / mists up quickly. That part will be shorted and needs to be removed. Hope that the part is a cap which is very common.

Once you find this part, remove it and check the resistance to ground again. Is the resistance higher now with the shorted part removed ?

Then test again if the 3v3 LDO rail returns to normal operation.

[arber1232]

Re: HP Pavilion x360 14m-dh0000 no power

Remove all power. Configure your adjustable power supply to 1 volt (NOT higher) and 2A-5A current.

Apply the red probe of your power supply onto the side with the low resistance; black power supply lead to ground.

Search for any part that may be heating up. You are effectively hunting for the shorted part with heat patterns. You can pour IPA (alcohol) and watch which part evaporates / mists up quickly. That part will be shorted and needs to be removed. Hope that the part is a cap which is very common.

Once you find this part, remove it and check the resistance to ground again. Is the resistance higher now with the shorted part removed ?

Then test again if the 3v3 LDO rail returns to normal operation.

My power supply with 1 volt current stay 0.2 A , I NOT CANT CHANGE CURRENT ON THIS POWER SUPPLY

[arber1232]

Re: HP Pavilion x360 14m-dh0000 no power

Can i inject 3 volt ? Or 2 volt becouse my psu with 2 or 3 volt in cshorts change current

[mon2]

Re: HP Pavilion x360 14m-dh0000 no power

No - for safety, we do not want to use a higher voltage. This is in case, there is a leaky mosfet downstream and that higher voltage from your power supply will kill your CPU.

Best to invest into a quality adjustable power supply for this servicing. Aliexpress has many but the Chinese New Year holiday just started so most are on vacation till the end of the month.

Do you have Amazon service in your region? They may have such power supplies.

See attached. Can you confirm if there is a low resistance to ground at 3DV3_AUX_S5 ?

The concern is to locate the shorted part that travel across many parts of your logic board. The part with the lowest resistance should heat up under this injection test.

This LDO rail appears to be powering the KBC controller.

[arber1232]

Re: HP Pavilion x360 14m-dh0000 no power

No amazon not supported in my country but i can find

See attached. Can you confirm if there is a low resistance to ground at 3DV3_AUX_S5 ?
yes is 0.8 k ohm
i find shorts . Shorts is ED4302 . Now light pulsed orange not stay stably

[mon2]

Re: HP Pavilion x360 14m-dh0000 no power

At your risk you can try your power supply @ 2 volt injection onto this rail and check for which part gets warm / hot. As noted, the main concern is that the CPU rail which is a low voltage rail, does not receive this voltage due to some leak.

It appears that this rail should not leak onto the CPU rail so it may be ok to test with the power supply you have.

At 800 ohms, the resistance is not super low so you really need to check around the logic board or use IPA (thermal camera is best) for any heat patterns.

[arber1232]

Re: HP Pavilion x360 14m-dh0000 no power

At your risk you can try your power supply @ 2 volt injection onto this rail and check for which part gets warm / hot. As noted, the main concern is that the CPU rail which is a low voltage rail, does not receive this voltage due to some leak.

It appears that this rail should not leak onto the CPU rail so it may be ok to test with the power supply you have.

At 800 ohms, the resistance is not super low so you really need to check around the logic board or use IPA (thermal camera is best) for any heat patterns.

i find shorts . Shorts is ED4302 . i remove tis and now light pulsed orange not stay stably
pin 17 is 18,5 k ohm

[mon2]

Re: HP Pavilion x360 14m-dh0000 no power

Very good. What is the voltage to ground on pin #17 LDO pin ?

You injected voltage and this part was heating up?

For service, a good power supply is nice to have.

Or you can consider the SHORT KILLER 30 model. Heard some fakes in the market but we bought from VIPPHONEFIX. Works well but display is a bit dim but works fine. We use at 0v8 setting and it can crack open a shorted tantalum capacitor.

[arber1232]

Re: HP Pavilion x360 14m-dh0000 no power

Very good. What is the voltage to ground on pin #17 LDO pin ?

You injected voltage and this part was heating up?

For service, a good power supply is nice to have.

Or you can consider the SHORT KILLER 30 model. Heard some fakes in the market but we bought from VIPPHONEFIX. Works well but display is a bit dim but works fine. We use at 0v8 setting and it can crack open a shorted tantalum capacitor.

voltage in pin 17 is 3,2 volt but change going 2,5 and not stably .. yes first in board heat D4301 i remove in pin diode i inject 2 volt and i find Ed 4302 is to hot

[mon2]

Re: HP Pavilion x360 14m-dh0000 no power

Check if the removed diode @ D4301 is defective.

Meter in diode mode, check if the diode conducts in one direction with your meter and should block in the other direction. Need to understand why the diode was heating up.

Also, where is 'Ed 4302'? Is if 'PD4302' ?