820-2936 green light no fan spin

sh33pz

New member
Hello,


This board was liquid damaged, repaired and working. Somehow a screw dropped on it sometime after, no idea how they pulled that off. Anyhow, I was missing PP5V_SUS and Q7840 was replaced, PP5V_SUS came back.

Sometimes the fan tries to move bit stops, it's not even a quarter spin, it's like a blip. I have PPVCCSA_S0_REG but I do not have PPVCORE_S0_CPU_PH2 or PH1

If I leave it on long enough, the CPU does get a little warm but, not hot, also when I plug in a mouse, it does light up but a USB drive stick does not.

Any idea what to look for next?
 

2informaticos

Administrator
Staff member
VCORE always stays at 0V?
Nor even a pulse when charger is connected, or triggering SMC_ONOFF_L?
Other coils should get voltage before VCORE appears; check for pulse on them at least.
Check for pulse at PM_SLP_S4_L and 5V_S3 coil first; especially if no fan movement detected.
Also try to start in SMC bypass mode...
 

sh33pz

New member
No pulsing all, when charger connected or triggering SMC_ONOFF_L, SMC Bypass, the fan does come on but no boot or chime.

Is it something with the bios/traces or clock signal?
 

2informaticos

Administrator
Staff member
"No pulsing all"
Nor even PM_SLP_S4_L?
Do you get 3V3_S5 and 3V3_SUS?

"SMC Bypass, the fan does come on but no boot or chime"
Board stays on then?
 

sh33pz

New member
no pulsing PM_SLP_S4_L it's a steady 3.3v, SMC bypass board stays on "fan stays going" I do get 3V3_S5 and 3V3_SUS 3.3v each.
 

2informaticos

Administrator
Staff member
In SMC bypass, do you get voltage on all coils, less the CPU ones?

I was interested for 3V3_S5/SUS in normal mode, when the board doesn't start...
Check if AVREF_SMC voltage is present.
 

sh33pz

New member
3V3_S5/SUS without bypass is 3.3v and SMC bypass is 3.3v as well.
AVREF_SMC is 3.3v with and without SMC bypass

I get voltage on all coils except the PPVCORE_S0_CPU_PH2 or PH1 and PPVCORE_S0_AXG_R in normal and in SMC bypass

Also noticed ppbus_g3h is 12.6v normal but in bypass it's 12.33v, I assume that is due to me bypassing it? If not, then I guess SMC issues?
 

sh33pz

New member
The board stays on in normal mode, minus the vcore of course.
r7402, 7mv on pin 1 and 12.60v on pin 2. Even in SMC bypass, it measures the same
Also, resistance is 55k, which should be 90.9k, so I removed the resistor out of the circuit and it measures 90k to be sure it's good.
 

2informaticos

Administrator
Staff member
you don't get a pulse at pin1, at least?
ALL_SYS_PWRGD is high?
Do you get 25MHz at pin 9/U2800?

If you get 0V at pin 2/U7400 without enable present, I recommend you to change U7400.

Check all SPI Bus Series Termination resistors and check for corrosion around U6100.
You can also try reflashing BIOS.
 
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