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iTurbo

macrumors 6502
Original poster
Sep 9, 2008
316
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Recently I installed an SSD into a 2010 iMac. It's my Mom's old one and I'm fixing it up to give to my 11 year-old nephew.

The iMac is running great and I'm still in the midst of updating it back to High Sierra (from 10.6.4 Snow Leopard on the original DVD install discs).

It turns out the fans are running high all the time. I had a little bit of trouble with the LCD temp plug, but other than that no trouble at all following the ifixit.com repair guide.

I installed MacsFanControl to see what was going on, and there is a temp sensor called "Platform Controller Hub Die" that is stuck on 138'F no matter what. Another odd thing is that the HDD temp sometimes shows temp well below the ambient temp. I'm pretty sure one of these two is the culprit and I'd like to have it run normally rather than using MFC.

I don't remember messing with any other temp sensors other than the ones for the HDD and LCD. For the HDD sensor on the new SSD, I replaced it with one for a Apple optical drive sensor and simply taped it down to the SSD case right near the SATA plug.
 
Recently I installed an SSD into a 2010 iMac.

It turns out the fans are running high all the time. I had a little bit of trouble with the LCD temp plug, but other than that no trouble at all following the ifixit.com repair guide.

I installed MacsFanControl to see what was going on, and there is a temp sensor called "Platform Controller Hub Die" that is stuck on 138'F no matter what. Another odd thing is that the HDD temp sometimes shows temp well below the ambient temp. I'm pretty sure one of these two is the culprit and I'd like to have it run normally rather than using MFC.

I don't remember messing with any other temp sensors other than the ones for the HDD and LCD. For the HDD sensor on the new SSD, I replaced it with one for a Apple optical drive sensor and simply taped it down to the SSD case right near the SATA plug.
I think you need to install this In-line Digital Thermal Sensor for the new SSD:
https://eshop.macsales.com/item/OWC/DIDIMACHDD09/
 
I think you need to install this In-line Digital Thermal Sensor for the new SSD:
https://eshop.macsales.com/item/OWC/DIDIMACHDD09/
The problem with manual control of the fans is that you must pay attention to the temps and control them. I had to do that when OWC was back ordered on that harness for my 2010 and disliked it. I also hated the sound of the fans spinning 100% during boot up till the app kicked in.

While the OWC sensor certainly works, there is an alternate for the 2009–10 only. An optical drive sensor can be plugged into the motherboard and taped to the drive. This one, for example:
https://www.amazon.com/Eathtek-Repl...pons&keywords=2010+optical+drive+sensor&psc=1

You can also find used system pulls on eBay for less if you don’t like the idea of spending $10.

To be clear, the optical drive sensor works in 2009–2010 21.5” and 27” iMacs only. 2011-on are wired differently and the OWC temp sensor for those years is different, too. Older 20” and 24” iMacs do not need these.
 
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The problem with manual control of the fans is that you must pay attention to the temps and control them. I had to do that when OWC was back ordered on that harness for my 2010 and disliked it. I also hated the sound of the fans spinning 100% during boot up till the app kicked in.

While the OWC sensor certainly works, there is an alternate for the 2009–10 only. An optical drive sensor can be plugged into the motherboard and taped to the drive. This one, for example:
https://www.amazon.com/Eathtek-Repl...pons&keywords=2010+optical+drive+sensor&psc=1

You can also find used system pulls on eBay for less if you don’t like the idea of spending $10.

To be clear, the optical drive sensor works in 2009–2010 21.5” and 27” iMacs only. 2011-on are wired differently and the OWC temp sensor for those years is different, too. Older 20” and 24” iMacs do not need these.
Was your reply responding to me (since you quoted my post), the OP, or both? I couldn't quite tell.

Anyway the OP did try an "Apple optical drive sensor" already.
 
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Yup, I used Apple optical drive temp sensor #593-0493 from eBay:

https://www.ebay.com/itm/Apple-iMac...ensor-Cable-922-8194-PN-593-0493/262061276596

The auction lists it as being for a 20" iMac, but it plugged in and seemed to fit alright.. It looks different than the one posted by mikehalloran though, and a different part number. Maybe I used the wrong one?!

Things that seem "odd" about MacsFanControl....
1. It doesn't give me the LCD temp sensor reading at all, even though I know it is physically there.
2. The temp sensor for the SSD (the optical drive one I used) shows temps at below ambient temp, which makes no sense.
3. What is the Platform Controller Hub Die anyway? I'm certain I didn't mess with anything like that while inside the iMac.
 
What is the Platform Controller Hub Die anyway? I'm certain I didn't mess with anything like that while inside the iMac.
If you pulled the screen, yes you did.

Although it's possible to install an SSD without removing the screen, iFixIt recommends doing so. You did not reattach one of the small plugs correctly—I'm betting the one that's inline between two cables. I did the same thing the first time I did a 2010.

To replace the NV RAM battery, one must remove the Logic board (it's on the back side) and the screen must come off for that. Only the late 2009–10 are like this.

If the sensor you used passes current, it's not the cause of your problem. If it doesn't pass current, there's an open circuit and that will blast your fans at 100%. This is true for the other two sensors that are in there, also. Any open circuit will cause the problem you have.

When I replace my 2010 (soon), I will do a pictorial without all of the extra, unnecessary steps in the other tutorials out there when I pull the 2TB SSD out.
 
Last edited:
Recently I installed an SSD into a 2010 iMac. It's my Mom's old one and I'm fixing it up to give to my 11 year-old nephew.

The iMac is running great and I'm still in the midst of updating it back to High Sierra (from 10.6.4 Snow Leopard on the original DVD install discs).

It turns out the fans are running high all the time. I had a little bit of trouble with the LCD temp plug, but other than that no trouble at all following the ifixit.com repair guide.

I installed MacsFanControl to see what was going on, and there is a temp sensor called "Platform Controller Hub Die" that is stuck on 138'F no matter what. Another odd thing is that the HDD temp sometimes shows temp well below the ambient temp. I'm pretty sure one of these two is the culprit and I'd like to have it run normally rather than using MFC.

I don't remember messing with any other temp sensors other than the ones for the HDD and LCD. For the HDD sensor on the new SSD, I replaced it with one for a Apple optical drive sensor and simply taped it down to the SSD case right near the SATA plug.

The platform controller hub die is the temp sensor that was on the HDD that you replaced with the SSD. It will default to 138* because the actual sensor isn't present. You just have to manually adjust the HDD fan to a normal level and use the other temp sensors to control the other fans like CPU, and ODD. Yes you can go to the expense of getting another temp sensor and trying to get it to work but it's really not necessary if you have a span speed controller.
 
It will default to 138* because the actual sensor isn't present
Which gives an open circuit,

As long as that circuit is open, this will be an issue. You have 4 choices with a late 2009–2010:

1. Buy this OWC harness and temp sensor:
https://eshop.macsales.com/item/OWC/DIDIMACHDD09/

2. Find a new or system pull iMac optical drive temp sensor. Plug it into the socket of the original. and tape it to the SSD
http://www.powerbookmedic.com/27-iMac-Optical-Drive-Temperature-Sensor-p-22249.html

https://www.ebay.com/itm/OPTICAL-DR...908833?hash=item5b3dfb6261:g:Md8AAOSw5YNZr2Sh

3. Reuse the original. Strip the wires and twist together shorting the circuit and tape over the bare wires. Without that spinning heat pump (usually a WD Black), it's generally agreed that this does no harm. I don't disagree having never seen a problem that I would associate with a shorted temp sensor when an SSD replaces the HDD. Can't bring myself to recommend this approach.

4. Use one of the crapware utilities to control the fan. This is unacceptable, IMO. It's not that you can control the fans—it's that now that you have to. I would never let a Mac leave if I knew that the fan will come on full until the extension kicks in.

With the 2011–14: (1) uses a different temp sensor. (2) & (3) won't work. 4 is still unacceptable IMO.

2011 sensor only
https://eshop.macsales.com/item/OWC/DIDIMACHDD11/

2012–on sensor (same as 2011) with tape kit for the 27""
https://eshop.macsales.com/item/OWC/DIDIMACHDD12/

2015–2019 iMacs can often get away without the sensor unless the fans go nuts — it depends. I use painters' tape to hold the assembly together and test. If the fans stay quiet, I tape the screen in. If they come on full, I install the sensor first.
 
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