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Model A1225 / Mid 2007 and Early 2008 / 2.4, 2.8, or 3.06 GHz Core 2 Duo processor

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Fans full power - sensors not detected - shuts down after time

Hi Everyone,

I have a 24" iMac 8,1 when the fans started a week or two ago going at full speed all the time. I opened it up and could see that all sensors were connected properly.

I then installed fan control and sensors and notice that there was not a sensor listed for cpu temp! there also isn't one for gpu either!

If i leave it on and do something intensive it just turns itself off after 10 mins or so. the temperatures look good at that time...?

I then rebooted and ran the apple diagnostics and got:

4SNS/1/40000000 TMoP- 130.000

I've opened it up everything looks ok and even stripped it down (logic board/graphics card out) and still no joy. I even put a new gpu in and still have the same problem so sensor must be ok...

Any ideas?

Answer this question I have this problem too

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Ok psu is good as i swapped that too...

anyway...

UPDATE

I've fixed it (and am probably the first one too based on hours of searching the web)

The problem?

You wouldn't believe it ... a bad CPU!

I had an old 2.4 from and 07 iMac surprised it worked but thought id test it and it booted lovely fans normal and all temperatures were back!

Ever heard of that?

I am going to order a new correct cpu - it did have a 2.8 but will the 3.06 drop straight in as it was also offered at that spec?

Cheers all!

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Wow! what a lark. I've never encountered that one.

by

Aha! Someone else with a similar problem. I have a late 2008 unibody Macbook Pro. Fans at max all the time even with cpu load below 10%. Fan control apps no use. All I get is 0° and 0rpm. iStat nano shows only HD temp (no battery, CPU, or GPU) even though my battery works but does not show up as installed. I don't have access to the Apple hardware test and nowhere near an Apple store.

I'm confused - this problem was or was not solved with a new logic board? One post says using a new board did not help, but the "**update**" says it made it work.

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Did you apply a fresh coat of thermal paste and did you use a good quality one on both the CPU & GPU's?

I use what IFIXIT sells: Arctic Silver Thermal Paste and using the cleaner to remove the old junk Arctic Silver ArctiClean.

You will need to look at the heat sink for any pin holes as the heat transfer tube is filled with a liquid which if it leaks out looses its ability to transmit the heat to the fins.

You may also want to try a different fan & temp monitoring application. I like Temperature Gauge Pro. I've seen issue with some of the other applications out there were this one have not failed me. Just make sure you don't have both running at the same time.

Update

Hi Dan,

Not sure if i mentioned this but even with fans on full power *both boards) it will switch itself off randomly still. I assumed it was overheating so put on compound but made no diffenece. did an dmc and pram reset no dice.

Also again snot sure if i mentioned - i have used 3 different temp sensor programs and none of them even discover the odd, hdd or cpu sensors (i mean not even reporting 0128 or anything they ar just not there!) on both boards?

I then took the board out and put in my working 08 iMac... problem still happened.. so i am really stuck - could it be a bad cpu or wireless card? clutching at straws now

Arctic Silver ArctiClean Image

Product

Arctic Silver ArctiClean

$9.99

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Hi Dan, I checked the compound yes any idea abut the error itself?

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You may want to check out this CNET article: How to invoke and interpret the Apple hardware tests

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Hi All,

An updare on this - wasted more money and still stuck... so i put in a new logic board...and guess what.. same problem? when i run about 5 different temp gauge programs none show the od temp, cput temp or the hdd temp - despite all being plugged in? so i could have another logic board ssame problem (unlikely?) or its something else... helP!

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Dan - Did you make sure the sensors where plugged in correctly? Review this IFIXIT guide: iMac Intel 24" EMC 2134 and 2211 Hard Drive Replacement Step 14. Are you sure you have the correct sensors plugged in per the markings on the logic board?

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Did you try AHT again? To see if it popped up with the same error as before. I agree swapping out the logic board should have fixed it.

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have you tried doing a SMC reset?

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Dan Wilderspin will be eternally grateful.
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