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820-2936-B Early 2011 13" Macbook Pro fan/failed sensor

wrbailey

wrbailey

New member
4SNS/1/C0000008:TC0C -- 124

Error kicked out from AHT.

Turns on, chimes, after about 5 secs the fan starts going full speed.

Anyone know which "sensor" that is not working or which area of the board that is referencing?

I looked in the hardware profile, under power and it says charger voltage: 12.26v

Is that lower than it should be? It's an OEM brand new from Apple 85w charger. Bad SMC?

Thanks!
 
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dukefawks

Administrator
TC0C is CPU diode, R4910 is PECI and is the digital signal. Problem will be around U5510. Also run ASD EFI non of this built is crap..
 
wrbailey

wrbailey

New member
U5510 Measurements (diode shows nothing shorting to ground)

PIN1 3.24V
PIN2 1.1V
PIN3 0.58-0.59V
PIN4 1.05V
PIN5 0.60-0.63V

PIN6 3.28V
PIN7 3.23-3.28V
PIN8 3.24V
PIN9 3.22V
PIN10 0V (GND)

Is it normal for the u1800 (PCH) to get pretty hot?
 
wrbailey

wrbailey

New member
I ran EFI ASD. Only thing that failed was the TC0C (just like in the built in diag crap.), as you mentioned earlier. Said SMC I/0 Fail as the warning.

U5510 has the dot in the top left corner (so that is PIN1, confirmed in BV as well)
Goes does left side and then upper right is PIN6, goes down to PIN10, which is ground (0V.)

Those are the measurements I got. I can measure again when I get home, but I measured once and then pulled the power and measured again. I did have one discrepancy where only ONCE did PIN 8 show 0.010V. However I tried 5 or 6 times again, even letting the board sit there with the fan on full speed and it wouldn't go low again.

apparently I've measured all wrong. or my memory in the AM isn't doing well. Looks like the right side of the chip should be PIN10 top right and going to PIN6 on the bottom. (pulled from Microchip's datasheet).

Swapping the Pins does make a little more sense...??

PIN1 3.24V
PIN2 1.1V
PIN3 0.58-0.59V
PIN4 1.05V
PIN5 0.60-0.63V

PIN10 3.28V
PIN9 3.23-3.28V
PIN8 3.24V
PIN7 3.22V
PIN6 0V (GND)
 
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dukefawks

Administrator
If there is a SMC IO error more sensors should be failing. Is ASD continuing on error? But there is an issue on the data bus for sure. So either dead U5510, SMC or PCH. Measure diode mode on pin 9 and 10.
 
wrbailey

wrbailey

New member
I did set ASD to continue on error instead of stopping on error. That is the only error that is kicked out. Everything else passes.

I measured all PINS on U5510 last night and none, other than ground (obviously), were anywhere close to short (all were over 0.4xx)
 
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dukefawks

Administrator
Remove R5222/23 and measure diode mode on both sides, then run ASD with them removed again. As U5510 contains 3 sensors when SMC IO would fail all s sensors would not read.
 
wrbailey

wrbailey

New member
PIN 9/10 both have 0.515 diode measurements

R5222/23 removed I get diode mode:

R5223 pin1: 0.558
pin2: 0.554

R5222 pin1: 0.560
pin2: 0.559

Ran ASD with resistors removed... Still only TC0C -- CPU die - Digital Core 0 "ERROR - SMC I0 failed"

Is this bad news?
 
wrbailey

wrbailey

New member
I did not check R4910. I will when I get home this afternoon from work.

To quote one of the best movies, "So you're tell me there's a chance..."

Haha, thanks again. I'll check back once I measure R4910 and replace the resistors.
 
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