Hi Guys need some help please got this laptop to repair and it would not power up so i removed the mother board from the laptop and tried to power it up i noticed that pu401 3.3v power ic was getting hot so i removed it and also the output capacitor as it was short to ground thinking this was the fault but in further investigation i have more power supplies shorted to ground.I have attached some pics with the shorted to ground parts in red and the removed items in yellow any help to trouble shoot the motherboard would be much appreciated Thanks in advance .
lenovo 80nj motherboard short to ground
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Re: lenovo 80nj motherboard short to ground
u must locate shorts. wipe solder from PJs to locate on which side is short -
Re: lenovo 80nj motherboard short to ground
Stuff near the CPU is most likely not shorted to ground. CPU Vcore line will have a very low resistance to ground, it's perfectly normal.OpenBoardView — https://github.com/OpenBoardView/OpenBoardViewComment
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Re: lenovo 80nj motherboard short to ground
short means resistance lower than 2-3ohm, higher is ok walue for high current ICs like CPU and GPUComment
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Re: lenovo 80nj motherboard short to ground
ok thanks guys so that would explain why my output of 1.5v ics are showing up as connected to ground.Your never to old to learnComment
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by playithello everyone , working zebronics power suply 450 watts , 5v ,3.3v givin short to ground black wire, also in circuit at output, resistor was charred but shows right values , after removing resistors 39ohms, 51 ohms, there was no short , no continuity beeps with ground , but after replacing new resistors (now i am not switching it on) ,again short still exists . when i put bigger ohm resistor like 100k ohm , no short beeping sound comes , lower ohm resistor gives continuity beeps ,other big ones donest , as its a working psu , i am confused what to remove now or how to go further now .
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by gaelicanHi,
I am working on an Asus ROG laptop repair. I was able to find that there is a short on the motherboard, and the 20 volts from the charger only gets to the first mosfet before disappearing.
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