3330 - CPU Core PECI

[Alan.L]

i can't find any corrosion and passed ASD. Fan goes high, load osx fine.
however, MRI show CPU Core PECI error sensor error.


where should check next?

ASD OS show error:

 

[aprendiz]

Diode mode on SML_PCH_1_CLK and SML_PCH_1_DATA??

 

[Alan.L]

diode mode on sml_pch_1_clk and sml_pch_1_data??

sorry, I'm late, now I am back at it again

sml_pch_1_clk = 0.530
sml_pch_1_data = 0.528

 

[2informaticos]

Check Q5050 and resistors/traces around it.

 

[Alan.L]

Q5050


pin1 SMC_PECI_L_R. has 50 ohms to ground.


SMC is shorted?

 

[2informaticos]

Remove R5052 to see where the low value remains.
For me, seems to be very low, unusual.
Can you confirm other value from similar board?

 

[Alan.L]

i've removed R5052, the low value still remains on SMC_PECI_L. Bad SMC? any more way to confirm it is smc?

i don't have any boards, don't suppose you have 2915 board to check for me?

 

[2informaticos]

Someone gave me the reading from one 3330.
Diode mode aprox .710 with red probe to ground; 1. inverting probes.
His board doesn't work (liquid spill), but the reading should be good.

Do you also get low value at R5054?

 

[Alan.L]

Diode reading with R5052 removed

pin1 (SMC_PECI_L) = 0.048

on a known working board i can confirm 0.706 is correct diode mode reading on SMC_PECI_L with R5052 removed.
i didn't want to waste time, so i had to use the 3330 board that without ethernet,firewire and sd reader because i had to remove R3943 .

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diode mode on R5054 = 0.245

good board = 0.276

 

[2informaticos]

If the PECI issue is on SMC side, change it...

 

[Alan.L]

Board is fixed after i replaced the smc. Yes Smc was the culprit ?. Thanks 2informaticos.

 

[2informaticos]

You was lucky enough to find a low value to point in a correct direction...