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(SOLVED) 820-3209 no power

Jeffotskie26

Jeffotskie26

Member
a1466 no power green orange light present no fan spin

tried smc bypass fan is on very high no display (my 1stime tried smc bypass)

8.41v pin 1 2 @F7040 PPBUS_G3H

U7600
3 = 3.2V
13 = 5.1V
14 = 5.1 V

PM_SLP_S3_L 3.3V
PM_SLP_S3_R_L 3.3V

L7630 1.0V
L7100 0.9v
L7330 1.3V
L7550 0.006v diode to ground 0.003
L7510 0.008v diode to ground 0.003

is it bad CPU?
 
2informaticos

2informaticos

Administrator
Staff member
Ivy Bridge CPU has very low values as normal.

If board stays on in SMC bypass mode, there is a problem with SMC some I/V sensor (pages 45/46).
Start checking SMC_DCIN/PBUS_VSENSE and SMC_DCIN/BMON_ISENSE.

Post U7400 voltages; pins 40, 24, 15, 2, 1.
 
Jeffotskie26

Jeffotskie26

Member
U7400
40 5.0v
24 5.0v
15 5.0v
2 8.32v
1 0.068v

SMC_DCIN 2.0v
PBUS_VSENSE 0.9v
SMC_BMON_ISENSE 0.0v
SMC_DCIN_ISENSE 0.0v
SMC_DCIN_VSENSE 0.0v
 
Jeffotskie26

Jeffotskie26

Member
after i remove Q7950 now got ALL_SYS_PWRGD 3.3v
and the fan is spinning. need to replace q7950?

update i tried ireplace q7950 ALL_SYS_PWRGD missing again
 
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2informaticos

2informaticos

Administrator
Staff member
Forget about it, is not really needed.
Something wrong with its input resistor dividers.

Is the board working now?
Check for video and USB activity.
 
Jeffotskie26

Jeffotskie26

Member
it is look like working cpu is heating fan is running normal, battery is charging.
but i dont see backlight/display on the screen and keyboard.
 
2informaticos

2informaticos

Administrator
Staff member
Didn't think to test external video?
Also check Caps Lock light reaction.
You didn't say anything about USB activity yet...
 
Jeffotskie26

Jeffotskie26

Member
tried external video still no display
got usb activity
u8100 is overheating? hotter than cpu dont know if this is normal
fan running high
caps lock no reaction.
 
2informaticos

2informaticos

Administrator
Staff member
"got usb activity"
Are you 100% sure?

HOW TO collection

I hope this "How to" collection will help our members. I will possibly modify this post in time, if updates available. Trigger SMC_ONOFF_L (PMU_ONOFF_L): It reffers to simulate power button function, when the keyboard is not connected. We need to do this when we work with the board...
boards.rossmanngroup.com boards.rossmanngroup.com
 
Jeffotskie26

Jeffotskie26

Member
this solved. found short on C1754 PP1V5_S3RS0 after this cap removed unable to supply 1.5V
checked r7850 on pin 1 PP1V5_S3RS0_FET_R is 1.5V pin 2 is 0.3v. i just jumper R7850 in order to supply 1.5V to PP1V5_S3RS0
thanks!
 
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