820-2914 missing PPVCORE_CPU & PPVCORE_GPU

Ryanlen2

Member
Board had damage had minor damage around U6900. Came with no fan spin and no green light. Regained green light and fan spin but now have no GPUVCORE and also missing CPUVORE. I have already told customer about possible GPU problems in the future but they insist to try to repair. Im not great with CPU stuff so Im not really sure where to go from here. Thanks.

CPUIMVP_PWRGOOD - 0.050v
SYS_PWROK_R - 0V
PM_S0_PWRGOOD - 0V


PP3v3_S5 - Present
PP3V3_S0 - Present
 
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Ryanlen2

Member
Im sorry I thought you just meant CPU stuff.

L7630 - 1.057V
L7220 - 4.98V
L9560 - 1.509V
L9510 - 1.021V
L7330 - 1.502V

Thanks.
 

Ryanlen2

Member
I have previously replaced 7400 and R7402.

VCC - 4.92V
VDD A/B - 4.95V
TON - .543V
EN - 2.606V

R7402 - 90k

Thanks
 

2informaticos

Administrator
Staff member
Check resistance to ground at L8920.
Post U8900 voltage, pins 16, 22, 14, 29.

New version of Tiresias Killer can disable GPU for 820-2914 MLB.
 

Ryanlen2

Member
resistance to ground at L8920 - 10.6Ohm

u8900

16 - 4.43V
22 - 4.94V
14 - 12.58V
29 - 3.296V

Thanks


Should I try replacing U8900 and Fets?
 
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Ryanlen2

Member
Replaced U8900 and now have 1.1V on GPU Vcore.

So if I get CPU_VCore back then it should POST and turn to .9V?

Thanks
 

2informaticos

Administrator
Staff member
Did you get CPU VCORE voltage?
It should post if it drops from 1.1-1.2V to 0.8-0.9V aprox, after few seconds...
 

Ryanlen2

Member
Customer backed out of this repair. So I guess I will never know if this could have been fixed. Thanks for all the help.
 
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