820-00281-A No power

twitchedonjay

New member
Hey I have a 820-00281 Motherboard with no power. No water damage but inside was really dusty. I got the following readings

ppbus_g3h = 12.61v

PP3v3_G3H = 3.4v

PP3v3_SUS = missing

PM_BATLOW_L = missing

PP3V0_G3H= 3.0v

PCH_INTRUDER_L= 2.8v

PM_DSW_PWRGD = missing

PM_SLP_SUS_L= missing

RTC_RESET_L= 3.0v

PCH_SRTCRST_L= 3.0v

3V3_S5 = missing


Can you please help me troubleshoot this unit?
 

twitchedonjay

New member
Okay i tried with the hz setting on my multimeter and got 32.76khz on sysclk_clk32k_pch (u1900 pin 10)
 
Last edited:

JohnB8812

New member
Yeah which makes me think the SMC is possibly pulling it down similar to older machines. Inspect near U7000 for corrosion as well. I think one or the other could be keeping PPBUS low which explains why many of the voltages you are missing are missing
 

twitchedonjay

New member
So would the crud around U7100 cause anything. its EXTREMELY minor and can only be seen under the scope but there. I went ahead and did a beep test to check short to ground. I have beep on:

CPU_VCCGTSENSE_P

CPUCORE_ISUMN

CPU_VCCSENSE_N

Are these suppose to beep due to low resistance or are these lines shorted?
 

2informaticos

Administrator
Staff member
I don't exactly know the corresponding values for your CPU.
But yes, CPU rails have usually very low values...
 
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