(347) 552-2258 [email protected]

820-3115 - Not turning on / Fan goes to full speed

M

mushr00m

Member
Doesn't turn on.

Fan start normal and then goes to full speed

ppbus = 12.51
PP3V42_G3H = 3.44V
PP5V_S5 = 4.94
PP5V_S3 = 0V
PP5V_S0 = 5.05



Should I replace U7200?
 
2informaticos

2informaticos

Administrator
Staff member
"PP5V_S3 = 0V
PP5V_S0 = 5.05"
That is not possible!
S0 voltage derives from S3.
Unless you have a broken trace to the point where you've checked 5V_S3.

Any history available?
Do you get CPU core voltage?
Tested in SMC bypass mode?
 
M

mushr00m

Member
I don’t have a detailed history of this machine — it arrived a long time ago, and I remember working on it briefly before setting it aside. Unfortunately, I don’t recall exactly what was done.


At some point, I replaced the U7200, but it might have come from a donor board and could potentially be faulty — I’m not sure.


Just to clarify, PP5V_S3 is reading 5V as expected. (My mistake somehow yesterday)


Regarding the CPU core voltage, I’m not sure which specific line you’re referring to.


I haven’t tested the SMC bypass mode yet.


Any suggestions on the next steps?
 
M

mushr00m

Member
Coils and voltage below. Seems to be something related to L7550

L3895 = 2.49
L7760 = 1.79
L7520 = 1.11
L7510 = 1.11
L7550 = 0V
L7100 = 0.910
L7630 = 1.05
L7030 = 12.50
L7330 = 1.48
L7260 = 5
L7220 = 3.29
 
2informaticos

2informaticos

Administrator
Staff member
Do not expect iGPU voltage yet.

CPU core stuck at 1.11V means the board doesn't really boot.
Check if PLT_RESET_L goes high.
Try known good BIOS.
 
M

mushr00m

Member
By the way, I tried using a BIOS from another 820-3115 donor board, but I’m not sure if that BIOS was functional — unfortunately, it still didn’t work.


I do have a CH341 programmer, but I’m not experienced with BIOS flashing or cleaning the ME region. Do you think I should give that a try?


If so, could you guide me through the process?
 
M

mushr00m

Member
I used the CH341A to erase and reprogram the BIOS with your file, but unfortunately it still didn’t work.


It’s possible I made a mistake during the process, since this is my first time doing it.


Also, I had asked earlier about using a BIOS from an 820-2936 board—would that be compatible?
 
2informaticos

2informaticos

Administrator
Staff member
Not compatible boards.

Check all SPI Bus Series Termination resistors and their traces/solders.

PCH/CPU may have corrosion underneath.
You can try to heat them with quality flux.
No need to melt the balls, just to burn eventually crap underneath.
 
M

mushr00m

Member
Checked all the resistors on SPI Bus Series Termination and everything is matching the schematics value.

heated with quality flux the PCH and still not turning.

Ohhh should I do it on the CPU too?

Maybe I melted the balls not sure....
 
2informaticos

2informaticos

Administrator
Staff member
Try heating CPU too.
You can probably get second hand board for good price.
Think if is worth to invest time on this.
 
M

mushr00m

Member
i will try heating the CPU and get back to you.

However my goal actually is to make this board work again. Not buy a second hand board.

I went to this subscription exactly to repair this board!
 
M

mushr00m

Member
1V05_S0_LDO = 10.5v
1V5_S0_REG = 1.50v

page 22

PP1V05_S0_PCH_VCCCLKDMI_F

1.00v

PP3V3_SUS_PCH_VCCSUS_US

3.28v

PP1V8_S0_PCH_VCC

1.8V


PP1V05_S0_PCH_VCCIO_SATA

1.03V
PP1V05_S0_PCH_VCCIO_USB


1.03v

PP1V8_S0_PCH_VCCTX_LVDS_F

1.8V

PP1V05_S0_PCH_V_PROC_IO

1.04v

PP3V3_SUS_PCH_VCC_SPI

3.28

PP1V05_S0_PCH_VCCDIFFCLK

1.03v

PP1V05_S0_PCH_VCCIO_CLK

0V


PP3V3_S0_PCH_VCCA_DAC

3.3



PP1V05_S0_PCH_VCC_DMI

0V



PP3V3_S5_PCH_VCCDSW

3.28V



PP1V05_S0_PCH_VCC_CORE



1.03V



Let me know if you need more lines.

I think I measure almost all of them.
 
You must log in or register to reply here.
Top