820-3115 No PPVCORE_SO_AXG

grmacs

Member
Fan spin for about 20 seconds. I believe I'm getting all the other vcore rails but noticed 0V @PPVCORE_S0_AXG diode there to Ground is 0V. Can I isolate and then run voltage to find the short? I noticed a ton of caps would be possible otherwise?...
 

2informaticos

Administrator
Staff member
"PPVCORE_S0_AXG diode there to Ground is 0V"
You are not curious to compare with good board?
i7 CPU is aprox 1 ohm to ground, as normal.

AXG voltage usually appears under high graphics load...
 

grmacs

Member
AHHHH... ok. well chasing down rabbit holes. THis shows USB activity (flashing on usb drive) but can't get a pram reset out of it or chime... No image/backlight. Had the heatsink off would that cause turn off as soon as 20 seconds?
 

grmacs

Member
PPVCCSA_S0_CPU is .97V
PPCPuVCCIO_SO_REG_R is 1V
Man I'm having a hard time figuring out if those are good enough. No good board for reference
 

2informaticos

Administrator
Staff member
When this board really boots, VCORE drops to 0.78V aprox.
Check voltage on output pin of L7510/20.
If you get USB activity, board boots; but VCORE doesn't respect known patron in your case.

Board still turns off in 20s?
 

grmacs

Member
Nice! Ram card was doing something to prevent stop progress at least. Switching Ram card out (either slot) I now get USB activity. BIOS Chip was swapped already today.

no chime/display image/backlight. No external display activity detected. Smc reset registers. Cant get it to pram reset.
 
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2informaticos

Administrator
Staff member
"there's USB activity"
For sure?
Flashing Link LED from USB boot pendrive?

"BIOS Chip was swapped already"
Picked from working board?
Even then, ME region must be cleaned...
 

grmacs

Member
Voltage to USB only. NO flashing light to indicate activity.

I did reflash the bios with cleanme no change. WOn't pram reset only SMC. NO chime. Fans start slow and eventually work their way to full high speed.
 
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