Model A1312 / Mid 2010 / 3.2 GHz Core i3 or 2.8 & 3.6 GHz Core i5 or 2.93 GHz Core i7, ID iMac11,3

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Replaced Power Supply - Multiple Sensor Failures

Had an iMac (27-inch, Mid 2010) suffering a power supply failure. Replaced the power supply and now the unit powers on, but the fans run constantly at 100%. Diagnostics show 17 of the 25 sensors (most of them temp, but a couple of voltage sensors) as "can't read". Trying to figure out if the sensor failures are due to a problem with the new PSU, or if they are simply a secondary issue that couldn't be diagnosed until the PSU was replaced. Any thoughts?

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edit: these are the failed readings according to diagnostics.

temperature (c):

ambient air - can’t read

cpu heatsink - can’t read

left heat pipe/fin stack prox - can’t read

lcd prox - can’t read

odd prox - can’t read

skin - can’t read

mlb prox - can’t read

ps board prox - can’t read

ps secondary heatsink - can’t read

ps primary heatsink - can’t read

power (a):

ac/dc - 0

current (a):

ac/dc - 0

voltage (v):

primary ac/dc - 33280

secondary ac/dc - 0


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Depending on the utility you used here you may need a newer version. What does AHT tell you?

Give this utility a try (free version): TG Pro does it report any of the thermal and fan sensors? Don't forget to disable your other utility before you run this one.

All of these sensors are part of SMC services so you could have blown the chip when the power supply went.

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My results are from MRI, so I'm going to guess they're fairly accurate. Didn't run AHT, since the MRI results are pretty conclusive. Thanks!


In that case, you blew the SMC as MRI goes directly to the hardware.


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