shorted mosfet and capacitor if processor is installed common in i7 and i5 series

[red_raian]

i encounter it in i7 and i5 series laptop, the mosfet and caps are shorted when i installed processor.

[piernov]

Re: shorted mosfet and capacitor if processor is installed common in i7 and i5 series

CPU VCore (and a bunch of other power rails) will always have low resistance to ground with the CPU on the board.

[red_raian]

Re: shorted mosfet and capacitor if processor is installed common in i7 and i5 series

@piernov how to test if low resistance to grounds. ( is that the very small black resistor) should i replace them all.

[Conste]

Re: shorted mosfet and capacitor if processor is installed common in i7 and i5 series

How big is the resistance?

I think a value of about 1-2 ohms is normal

[jasko_jacker]

Re: shorted mosfet and capacitor if processor is installed common in i7 and i5 series

normally in diode mode the value must not be 0000 other values could be acceptable, for example 0003 <i7-6500U <0007.

[piernov]

Re: shorted mosfet and capacitor if processor is installed common in i7 and i5 series

In diode mode meter can show 0.000. I personally don't use diode mode, I always use resistance mode, and for example Ivy Bridge mobile can show 1.5 ohm and it's fine. Some high-end desktop CPU will be lower than 1 ohm, some desktop GPU too. Never assume you have a short to ground on a high-power low-voltage rail.

[red_raian]

Re: shorted mosfet and capacitor if processor is installed common in i7 and i5 series

so guys it more than one resistor? it doesnt need to take off the resistor to know the resistance? right? i'm repairing laptop and i always failed to fix that kind of problem. thank you guys for guiding me.

[jasko_jacker]

Re: shorted mosfet and capacitor if processor is installed common in i7 and i5 series

in this case we are checking if the cpu is not shorted and more precisely we are checking the power of the cpu (+ vcore) we are not interested in the exact value of the resistance and this does not give us any indication that it is definitely working.
as regards the single resistor it depends on how it is positioned in the circuit.