replace the hard drive, how do I connect Hard Drive thermal sensor?

Does this work for 2011 iMacs? I know that they have a temp sensor built-in to the power cable for the HDD.

Also, the splice that you are making... is the new connection going directly from the fan to the temp sensor that you are taping to the hard drive? Are you bypassing the logic board all together then?

Thanks!

I also would like to know if this works for 2011 iMacs. I have an old 2005 iMac, could I use a temperature sensor from that?

The '05 iMac G5 temp sensor is the older 4 wire type. If it has Intel processor then it will have a 2 wire sensor that should work.

Hi Ben, how can I use this temp sensor with mid-2011 27" iMac? The mid 2011 iMac doesn't have a separate temp sensor. How can I attach the transistor temp sensor to the power cable? Thanks.

Ron

Mid-2010 and earlier iMacs with sensor cables that plugged into the hard drive are what I'm referring to. In spite of what others here are saying I have seen no evidence that there is any special firmware in these hard drives. ALL hard drives report a myriad of self-diagnostic information via SATA and SMART (see the pic on my June 6th post). The OS can rely on this data for fan and temp control. Apple thought it was safer for the HDD temp data to be sent directly to the Logic board to be analyzed by the OS. In 2004 G5 iMacs, 2006 White Intel iMacs, and 2007-2008 Aluminum iMacs, a discrete temp sensor was adhered to the hard drive to read temp independently of the drive's self-reported data. 2009 and 2010 iMacs used an external feed from the HDD's built in temp sensor to send the data to the Logic board. The 2011 models appear to have no separate cable to the Logic board so they must use the drive's built in temp sensor data via SATA. This means the solution should be software-based.

Marc66,

1 - Already applied my solution in over 50 iMacs

2 - yes, this transistor acts as a temperature sensor

3 - normal

4 - Yes, it works the same way as the original hd

5 - works perfectly

Att

Thank you Alexandre, I'll give it a try when I replace my HD

I performed the HDD replacement yesterday. Everything is working like a charm and thanks to Alexandre's solution for the Thermal Sensor replacement, I don't need any additional software to control my fan. It works just like before and shows a temperature around 40°C which is what I had with my HDD before.

You can find some pictures:

- Before: http://cjoint.com/?CLCppQ6dZOo

- After: http://cjoint.com/?CLCpqxAJmtP

- Thermal sensor detail: http://cjoint.com/?CLCprr2tXtd

- SSD detail: http://cjoint.com/?CLCpsly2bRK

Marc66, does it matter which pins on the transistor? Is it possible to solder the grey & black wires directly on to the transistor pins? I'm assuming it matters which colour lead goes to which pin, correct me if I'm wrong?

I am experiencing issues with a Hitachi drive and found this thread, very curious how this works as my sensor connector only has two pins?

I'll try the transistor solution whenver I get a chance I guess.

Hi could you please suggest a cable I could use for my 27" mid-2011 iMac to upgrade the main internal drive? I've tried the OWC cable with temp sensor, however, I noticed that the Apple HW test intermittently fails using this. Also with normal operations, the HDD fan goes up to 1100 thru 2500, and back down to 1100 often. I don't see this behavior with the original 1TB drive. Thanks for your suggestions.

-Ron

Here's what you'll need and more detail on the HD issue: Background Story and the needed part: OWC Complete Hard Drive Upgrade Kit including tools for all iMac 2011 Models. I should point out depending on the drive you get you may not even need this cable. As an example the Seagate SSHD drive can be used (one with the Apple logo on the box).

Hi! Wich HD model and brand are you using? Tnx!

The make is Western Digital (WD). Don't have the model info handy, but it's a current model 1TB Blue, iirc. The issue I found must have come from changes WD made to the drive's header pinout.

Thanks. In a few day I'll perform a similar task, same HD. But I will use the transistor-as-a-temperature-sensor idea.

This was very helpful. I have a mid-2010 iMac 21.5" that originally shipped with a Seagate drive. I replaced it with a WD Blue 1 TB and bought cable 593-1257-A.

I first had to cut the tab off the connector since the new drive didn't have a keyway/cutout for orienting the plug. It didn't work until I swapped the pins. (Turning the plug 180º didn't work for me.)

If I would have known all this ahead of time I would have bought a Seagate drive, though all's well after a little fiddling.

This is the most useful peace of information on this page, thanks so much for sharing. We replaced an iMac 27" 2010 1 TB WDC Caviar Black with 1TB WDC Desktop Blue, and needed to get the fan sensor refitted correctly to prevent the fan from running constant full blast.. turning the temp sensor connector 180 did the trick, awesome, GOLD STAR thank you

http://www.derman.com/iMac-Fan-Control

this is the best for Imac's fan's

i have it and i can control all fans to desired speed..

Thank you very much for the suggestion :) I know about this cable but it does not fit to the disc i have now.. and no cable exists for my disc and there is no need to it because is all time cold..i have the disc outside the case :)

The site you refer is one of the best for mac items.

Yes is annoying when you cant change items from your pc..Actually is my pc especially after one year passed after warranty and i didnt wanted to pay every year apple care if and when something going wrong... :)

After all my skills are enough to change processor or video card or power supply..and this is now out of case with a fan :)

Thank you for replying :)

i just wanted to give an idea here for people having problems with this !&%& disk..

Note that apple have inside a special firmware that even if you change the disc with same but not from Apple does not work..

You state your HD has a different connector than what the cable supports (Apples or OWC custom cable) can you explain? 3.5" SATA drives all use the same connector, do you have a 2.5" mSATA SSD? That does have a different connector. If so, their are adapters to convert. Also some HD vendors have changed their HD firmware on some of their drives to be compatible with Apple systems that use the internal SMART temp sensor (not all SMART HD's have a sensor). The real issue here is not custom firmware but a hole in the SMART standard on how temp was accessed from within the HD as it was never clearly defined in the standard.

I dont have the original hd because it crashed..lot of bad sectors....i change it with a 2.5 ssd which is dont have at all jumper connections my friend.. only the smart from the sata connection ..but is not so accurate..yes not all HD have this sensor.. these hd's have a dot

painted below . Yes you absolutely right but i know that they put inside and a firmware for accessing these data and these hd's are specially designed for Apple.

To jump the connector you must find a small cable in diameter take off the insulation and cut a small piece of the copper and put it one side inside the plug on the gray cable and the other side to black. but you must install and a third party software to control the fans then.... But just to know Apple does not recommend that only in the case that you put an ssd.. I Need to tell at this point that IFix it is a good site for mac and everything you find here (guides are well tested) .thank you.

Where in Oregon are you or maybe you can't say. The Apple guy I am using (not a Certified Apple Tech) suggested buying an external thermal cable from a 2008 model. I have a Mid 2010 IMac, replaced a WD with a 1TB WD and get that horrible fan noise. Don't trust using an Utility as HDD Fan Control and that costs $35 now. It's going to cost me more to pay this guy to swap out the cables. I damaged the LVDS cable so I am done trying to install anything myself again.

Dana - The '10 iMac models use a special cable per the HD vendor drive you are using. If your system had a Seagate drive you'll need to replace it with a Seagate drive etc... With that said, you CAN use a different vendors drive but you'll need to swap-out the thermal sensor cable with the correct one per the drive you are putting in. Why don't you create your own Question so we can review your systems issues to see what is up here as you could have a different problem.

Dana - Your right to be concerned about software over-rides. That only masks the problem and not addressing the issue will likely shorten your systems lifespan and/or wear out parts needlessly.

@beneshelman;

Thanks a lot for the explanation! :)

One question though: I've read that the late 2012 iMac (the 21.5" one) uses a custom firmware inside the HD, which is then read via the SATA cable instead. If that's true, how and where do you connect the red/black cable of this thermal sensor if I may ask? I'm not against soldering or connecting a "new" cable to my to-be-upgraded HD, but I'm a little confused on where this cable is connected to :)

And how does that work with the motherboard/EFI? I was always under the impression that the EFI, on new Macs anyway, nééded to read the temperature via the SATA cable directly into the HD's firmware… or is this also nonsense?

Thanks again for the help though!

Thanks again Beneshelman! :)

Installing that cable is a little above my comfort zone (primarily since I have no idea about the how and where), so I'll just give it a go without it. What's the worst that can happen after all? A fan spinning out of control can, if needed, easily be solved with a little bit of software. And that's the only thing that might happen, so I guess I shouldn't be worried ;)

As far as that HD you're currently testing: I'm not thát much of a heavy user that I absolutely need an SSD… I do use Photoshop and Illustrator pretty extensively, and I play an occasional game, but for me if I open up my iMac anyway, I want the fastest available. Doing that kind of work, which isn't difficult per sé but not my daily routine, I want to get the most out of it in one go, heheh.

@ Roaldastephansen - At first over-riding software was thought to be a good solution, but over time we have learned it's not as good as fixing the root issue which is installing a thermal sensor. Many a system has suffered from over heating as the software was not tuned correctly, and/or the fans failed as they were running to hard. In either case the cost of repair was higher than fixing the system correctly the first time.

TThanks siersbr. That was the easiest solution. I wrapped the pcb with tape in case of it touches some live equipment when i move it.

Bob what drives were you going from and what did you move to?

@Hell7- Actually an iMac that isn't filthy and plugged up with dust keeps it's drives at 29-35c

depending on the drive.