820-3437 motherboard acting weird.

[bridges_4u]

Hi there,

I have an 820-3437 motherboard which does not show any signs of life when using an OEM charger. But the magsafe light comes up when connected using a fake charger. While using a fake charger, the fan spins for may be 10 seconds and stops. Then the loop continues. Almost every power rail is up, but with 0.2-0.3 V drop. But I do not get a display, but sometimes does. While powered using the fake charger, the CPU seems to be burning hot. I got display at about 3 instances with the fake charger.

But with the OEM charger, no signs of life.

Any advises?

[mon2]

Re: 820-3437 motherboard acting weird.

CPU seems to be burning hot

Without a heatsink, this is normal.

Remain with the original charger only.

Start with the review of PPBUS_G3H and the PP3V42_G3H primary rails.

[bridges_4u]

Re: 820-3437 motherboard acting weird.

Hi mon2,

The CPU seems to be overheating with the heat sink. I shall post the voltage shortly.

[mon2]

Re: 820-3437 motherboard acting weird.

CPU is likely dead. Check the resistance to ground of the CPU power rail.

[bridges_4u]

Re: 820-3437 motherboard acting weird.

Hi mon2,

Then how does it give you a display sometimes? Are you talking about CPU vcore?

[piernov]

Re: 820-3437 motherboard acting weird.

Magsafe issue: https://logi.wiki/index.php/Magsafe_Sleep_Mode
POST issue is probably unrelated though.

[bridges_4u]

Hi mon2,

mon2

I found what the problem was. It was the 68k resistor in the pp3v42 circuit. I cant recollect what the part number is.

Replacing it solved the problem.

Thank you for the help and guidance.

Regards

[payam]

thanks a lot dear bridges
my problem also solved with changing 68k resistor R7012😍