A1237 2008 820-2179 fan spins 5 seconds then stops

[VinceLx]

Hello,
This board in good conditions, no liquid damage visible.
Green light on charger, fan starts and runs 5 seconds then stops. No display backlight, no chime, just very short flash on USB pendrive.

When fan runs I have:
ALL_SYS_PWRGD=3.42V
SMC_LRESET_L=3.3V
PPBUS_G3H=8.43V
SMC_PBUS_VSENSE=2.97V
SMC_PBUS_ISENSE=0.43V
SMBUS_SMC_BSA_SCL=3.46V
SMBUS_SMC_BSA_SDA=3.46V

After fan stops I have:
SMC_RESET_L=3.46V
SMC_LRESET_L=0V
ALL_SYS_PWRGD=0V
PPBUS_G3H=8.43V
SMC_PBUS_VSENSE=0V
SMC_PBUS_ISENSE=0V
SMBUS_SMC_BSA_SCL=3.46V
SMBUS_SMC_BSA_SDA=3.46V

If I trigger SMC_ONOFF_L fan spins again 5 seconds then stops.

Where to check to set PPBUS_G3H to 18.5V?

 

[2informaticos]

"Where to check to set PPBUS_G3H to 18.5V?"
Are you kidding???

See first what happens in SMC bypass mode.

When fan spins, do you get VCORE?
Still turns off when DDR modules are removed?

 

[VinceLx]

I expect PPBUS_G3H=18.5V when fan is spinning because on page 8 this value is mentioned. Maybe not correct value? No experience with this board model...

When fan spins:
VCORE=0.96V
CPU_PWRGD=1.07V Is this the expected value? It comes directly from ICH, if this is wrong, ICH is dead?

"Still turns off when DDR modules are removed? "
DDR is soldered on the board

 

[2informaticos]

8.4V is the correct voltage for PPBUS_G3H.

VCORE drops to 0.96V from higher start value?
What about bypass mode???

 

[VinceLx]

It's very fast, on digital Vmeter it seems to pass directly from 0V to 0.96V, I don't see higher value in between

SMC bypass mode: fan runs high speed 5 seconds, then stops. Same scenario after when pushing power button again.

 

[VinceLx]

Any idea how to continue investigating here?

 

[2informaticos]

You may have northbridge, or southbridge problem there.
Maybe broken solders/traces...

 

[piernov]

Check FSB_CPURST_L and PLT_RST_L.
Try to flash SPI ROM.

 

[VinceLx]

When fan spins:
FSB_CPURST_L=1.07V
PLT_RST_L=3.3V

I can read the SPI ROM, but when I try to erase before writing I got the message:
"Possible protection is enabled. Press "Unprotect" and check datasheet"
Is the chip dead, or is there any trick?

 

[VinceLx]

I used a known good SPI ROM chip, same issue, 5 seconds spins and stops. I will stop with this one.
By any chance, do you have any clue about this message when trying to erase the SPI ROM: "Possible protection is enabled. Press "Unprotect" and check datasheet"?

 

[VinceLx]

Strange enough, this message also appears on the known good chip I tried to erase. Using the same hardware and software (ASProgrammer 1.41) to flash BIOS, I never had similar issues when flashing A1286 or A1278 dumps. Any idea?