[RIP] 820-3476 green & red light no fan

[arnonabuurs]

I have a 3476 that had some liquid damage/corrosion under the U7200 which I replaced. Here some measurements:

PPBUS_G3H = 12.57
PP3V42_G3H = 3.42
PPVRTC_G3H = 3.34
PP5V_S5 = 5.02
PP5V_S4 = 0
PP3V3_S5 = 3.34
PP3V3_S4 = 0.45
PPVCC_S0_CPU = Pulsing from 0 - 0.59

U7501
Pin 12 SMC_PM_G2_EN = 3.42
Pin 21 S5_PWR_EN = 3.42
Pin 23 VIN = 12.57
P5VS4RS3_EN = 0

The PP5V_S0 Line goes from 0 to 5v and then turn off again.
U6100 checked seems OK, resistor and power going in same for U1950
Found a short in PPVCC_S0_CPU seems to be a trouble to test all C any ideas?

 

[dukefawks]

It is power cycling. What is resistance to GND on PVCC_S0_CPU?

 

[arnonabuurs]

There is none its shorted as mentioned above.

 

[dukefawks]

PPVCC_S0_CPU = Pulsing from 0 - 0.59

So no way it is fully shorted. Again, what is the resistance to GND?

 

[arnonabuurs]

Hi Duke,

I wrote -> "The PP5V_S0 Line goes from 0 to 5v and then turn off again", this measured on the fan's 5V pin

The PPVCC_S0_CPU gives me 0.06 and a beep when measuring resistance to ground

 

[arnonabuurs]

oh yes i forgot i measured that too that is correct its pulsing as well, and when I measure Short to GND I get a beep and 0.055 or 6

 

[dukefawks]

I only have a 2.6 board here to compare but a good 2.6 CPU measures 80 Ohm to GND on CPU Vcore. You measured diode mode but at 0.05 that will pretty much be the same in Ohm. o very likely the CPU is fried.

 

[arnonabuurs]

OK thanks, gonna work on another board instead