[SOLVED]820-3437 - Fan spins, No chime, No image on screen

Sykulski

Member
I have this 820-3437.

Liquid damage around SPI U6100. Burned trace between R6110/p2 and R6120/p1 fixed. Burned trace between R6102/p1 and C6100/p1 fixed. R6102 was replaced.

The fan is spinning but does not make the usual three times cycle. It starts spinning for 6-8 seconds. Then stops. Then starts again and keep spinning forever. On U6100 SPI i got 3.3V on pins 1,2,3,8 all the time. Pin 7 is 3.0V all the time. Pins 5,6 only got 3.3V while fan is spinning the first time. After the fan stops and starts again voltage is not coming up on these two pins.

I then tried flashing a new SPI chip but it did not help. Same issue so I have put the original one back.

PM_PCH_PWROK = 3.4V
PM_PCH_SYS_PWROK = 3.4V

What now?

Thanks
 

Sykulski

Member
I removed J6100 from board. All resistors around U6100 measure correctly according to schematics.

Still same issue.
 

dukefawks

Administrator
Only thing I can think of is another corroded trace from U6100 to the CPU or SMC. Remove U6100 and measure diode mode on all pins.
 

Sykulski

Member
Diode mode U6100 (off the board)

Pin1: 0.497
Pin2: 0.477
Pin3: 2.017 - (should this be so high? R6101 = 3.3KΩ, diode mode pin1 = 0.412)
Pin4: 0.002
Pin5: 0.508
Pin6: 0.508
Pin7: 0.462
Pin8: 0.408
 

Sykulski

Member
OK.

Diode mode. R6114-17 removed. U6100 still off board

Pin1: 0.501
Pin2: 0.480
Pin7: 0.468
Pin8: 0.408
 

Sykulski

Member
Diode mode with resistors R6114-17 removed:

R6114: p1 = 0.735, p2 = 0.484
R6115: p1 = 0.736, p2 = 0.515
R6116: p1 = 0.735, p2 = 0.515
R6117: p1 = 0.735, p2 = 0.505
 

dukefawks

Administrator
That all looks ok. Still looking at that 3V on pin 7. It should either be 3.3 or 0, have you checked the pull up resistor and traces are ok?
 

Sykulski

Member
Yes. From the beginning there was no R6102 because it was burned away together with the trace to C6100. So I replaced R6102 and C6100 and made a trace with battery wire between them. R6102 measures 99.8KΩ and continuity to C6100 and U6100/p7,8 is ok. I've got 3.3V on R6102/pin1 and 3.0V on pin2
 

Sykulski

Member
I got this one up and running after a long and lasting fight. It was the BIOS after all. I missed it because I accidentally flashed an A-revision BIOS but it is a B-revision board. But because the A-revision BIOS made same issues as the corrupted original BIOS it trolled me. After flashing correct BIOS for 820-3437-B and updating ME it is running smoothly. Thanks again for your time and effort Mr Duke. Please mark solved.
 
Top