Lenovo 15imh05h no power no turn on

[Lenovochris]

Lenovo 15imh05h doesn't turn on
After some poking around the motherboard once charger is applied 4r7 resistor in photo becomes too hot to touch,
My suspicions are that it's the MOSFET to the left of it,
I'm not the most experienced but I'm trying to learn can anyone advise in simple terms how I can test and identify the likely culprit, I understand 4r7 is getting hot because a lot of voltage is being passed through it.

Thanks

[mon2]

See attached.

Remove all power. Measure the resistance to ground of this same 4R7 resistor. Post the measurement.

This same resistor (PR409) is mating with the capacitor @ PC412. Perhaps the capacitor is shorted and this is causing PR409 to heat up.

[Lenovochris]

Ok thank you I will check and post back results thanks👍

[Bios Cracker]

See attached.

Remove all power. Measure the resistance to ground of this same 4R7 resistor. Post the measurement.

This same resistor (PR409) is mating with the capacitor @ PC412. Perhaps the capacitor is shorted and this is causing PR409 to heat up.

Additionally, if you couldn't find the culprit with the cold testing then you can use DC power supply to check for the heating components....most probably @PC412 should be the crusader. Any of the connections to PR409 could be responsible for making it hot. Thanks.

[Lenovochris]

See attached.

Remove all power. Measure the resistance to ground of this same 4R7 resistor. Post the measurement.

This same resistor (PR409) is mating with the capacitor @ PC412. Perhaps the capacitor is shorted and this is causing PR409 to heat up.

Top of resistor measures to ground 004.7
Bottom measures 000.2
THe 4r7 does look to have a line going down the centre of it. Like small damage I could be wrong

Capacitor in you board pic
Reads ol on right side and left reads 000.2 resistance to ground.
This capacitor gets too hot to touch when DC is applied.
Sorry if it's not clear

[Lenovochris]

see pic for line

[mon2]

Bottom measures 000.2

Can you confirm this is the measurement from pin # 1 - highlighted in yellow from my post?

If yes, this is a hard short to ground. It appears that the mosfet @ PQ401 is shorted to ground (drain & source pins are shorted).

Attached is what I believe is the reason for the short to ground of this resistor.

[Lenovochris]

Can you confirm this is the measurement from pin # 1 - highlighted in yellow from my post?

If yes, this is a hard short to ground. It appears that the mosfet @ PQ401 is shorted to ground (drain & source pins are shorted).

Attached is what I believe is the reason for the short to ground of this resistor.

Ok so
Pq401 top pins, so in yellow on diagram read 000.0 resistance to ground
Yellow on resistor read 000.2 then drops to 000.1 then to 000.0
Capacitor reads 000.0 on yellow To ground
Sorry I don't understand the diagram but I appreciate it.
Thanks

[Lenovochris]

This is the mosfet if it helps at all

[Lenovochris]

Can you confirm this is the measurement from pin # 1 - highlighted in yellow from my post?

If yes, this is a hard short to ground. It appears that the mosfet @ PQ401 is shorted to ground (drain & source pins are shorted).

Attached is what I believe is the reason for the short to ground of this resistor.

I just found this on AliExpress:
￡4.59 | 10PCS Original/New AONR32340C DFN8 3X3 QFN MARKING 32340C
https://a.aliexpress.com/_EwS6yFw
Would this be a suitable replacement for the MOSFET as I have some of these already
Thanks

[mon2]

No. One mismatch is that the original device contains 2 x Mosfets inside this package vs. the replacement that was linked is a single mosfet inside the same package.

Note the

S1 / D1 / G1 = first mosfet pins
S2 / D2 / G2 = second mosfet pins

From where do you normally shop? Digikey / Mouser / Arrow / RS ok for you?

The following should be suitable:

https://www.digikey.ca/en/products/d...T1-GE3/8572033
* change the link to suit your local site for currency

https://www.digikey.ca/en/products/d...C7208S/3855009
* change the link to suit your local site for currency

[Lenovochris]

No. One mismatch is that the original device contains 2 x Mosfets inside this package vs. the replacement that was linked is a single mosfet inside the same package.

Note the

S1 / D1 / G1 = first mosfet pins
S2 / D2 / G2 = second mosfet pins

From where do you normally shop? Digikey / Mouser / Arrow / RS ok for you?

The following should be suitable:

https://www.digikey.ca/en/products/d...T1-GE3/8572033
* change the link to suit your local site for currency

https://www.digikey.ca/en/products/d...C7208S/3855009
* change the link to suit your local site for currency

Thanks that's really helpful
Normally rs or AliExpress due to price.
I'll order 2 and get back to you when they arrive, thank you so much for your help so far👍

[Lenovochris]

MOSFET swapped nbut showing
Led 1 2 3 4 are pulsing when power applied
But no turn on no more short