27" Imac Temperature Sensor?

[lute]

Mid-2011 27" Imac was working great last night; this morning it was gray screen only with the Apple logo and gear spinning. Would not reboot normally or in safe mode. Did a hardware test and got the following:
4SNS/1/40000000:TAOP-44.183.
Apparently this code corresponds to Ambient Temperature Sensor/Cable, Optical Drive, Power.
Repeated the test twice and got the same results.

Was able to go into Single User Mode and use fsck tool. Then the Imac booted and seems to run OK.
Owned this machine 5 years and this is the first and only problem I have had.

What to do now? Best to just let it be?

 

[chscag]

Welcome to our forums.

Your 2011 iMac has three fans running all the time: CPU, Hard Drive, and Optical Drive. A temperature sensor controls the speed of the particular fan. Before doing anything else, you should make sure you have a good backup of all your data. Use Time Machine or cloning software such as Carbon Copy Cloner. Next, download a monitoring program that reads the temperatures and speeds of the fans plus other things. Most of us recommend iStat Menus. Keep an eye on things and keep up with backups. Instead of booting to Single User Mode, next time boot to Recovery (command plus r) and use Disk Utility First Aid from utilities to check your hard drive which is now 5 years old. You didn't mention which version of OS X you're running?

 

[pm-r]

Personally I'd suggest using one of the alternate FREE fan utilities and I had to quit using my iStat Menus many months ago as it was just using way too many resources and memory.
Check the alternates and what some other users say:
https://www.macupdate.com/app/mac/25230/istat-menus

PS: I have and use the same mid-2011 27" iMac.

PPS: And yes I do use and recommend using Macs Fan Control:
http://www.crystalidea.com/products?source=fancontrol_mac






- patrick
==========

 

[chscag]

Alternate fan monitoring utilities are fine and if you can find a free one that's reliable, great. However, I strongly suggest before using any kind of fan control software that you first determine the overall health of your iMac and I can't stress enough about making backups.

 

[pm-r]

Alternate fan monitoring utilities are fine and if you can find a free one that's reliable, great.

I sure agree with that and the other comments as well, and one reason I mentioned using the Macs Fan Control.app

Check the user comments at the sites if needed.






- Patrick
==========

 

[lute]

These are great replies and I thank you for them, Patrick and CHSCAG.
The IMac was acquired at a time when I could afford such a luxury. Now I need to keep it functioning.
The operating system is OS X 10.9.5.
I downloaded the Mac Fan Control app and got the following results: All fans are operating at minimum speed. Temperatures range from 43 at CPU Core 1 to a high of 63 at LCD Proximity. All of the others are around 55 degrees.

 

[chscag]

Keep an eye on the RPM of the three fans. If I remember correctly, my 2011 iMac CPU fan was always at around 1000 RPM. Great machine except for the lousy Seagate hard drives Apple put in them at that time. However, changing out a hard drive in a 2011 iMac is much easier than the one I own now. (2013 27" iMac) The newer iMacs are glued together whereas yours can be taken apart with a glass suction puller. See the instructions on ifixit.com.

 

[pm-r]

If I remember correctly, my 2011 iMac CPU fan was always at around 1000 RPM.

That's pretty good memory chscag, and I prefer to run my mid- 2011 27" just a tad cooler than Apple sets it using a custom mod in Macs Fan Control, and I still can't hear any fan noise:





- Patrick
==========

 

[lute]

All was good for a week and then the hard drive died.
Until I can get the parts to fix it I am trying to find a temporary solution.
Using a spare 32 gig flash drive I downloaded El Capitan OS X from my App Store purchases and then transferred to the drive.
Using the Option key all seems to proceed until it asks what drive to install to. When I pick the USB drive I then get a screen saying "volume contains an OS X installation which may be damaged". Tried erasing and reloading the flash drive and get the same message.
So my first question is: Is it possible to boot up directly from a flash drive with an installer on it? Can the installer application that is on the flash drive install to the same flash drive?
I am surpassingly ignorant of how all this works.

 

[pm-r]

Until I can get the parts to fix it I am trying to find a temporary solution.

Where's that backup drive that was mentioned several times here just recently???


If it was made with cloning backup software (CCC or SD! etc), all you'd have to do is select it as your boot drive and you'd be back up (no pun) and running.






- Patrick
==========

 

[lute]

No backup drive.
No backups either.

Charge: Wilful stupidity, carelessness, and sloth.
Plead: Guilty as charged.

 

[ferrarr]

Now you need two drives. One to put the installer on, and the other to install OS X onto. You only need 8gb to pu the installer onto.

You may be able to put the installer onto the USB, boot from the USB, and then partition the USB into two partitions. 8GB and 24GB, it could be worth a shot.

 

[harryb2448]

Be aware unless you use precisely the same drive that has died, the fans will roar. To overcome this go to OWC (macsales.com) as they sell an over rider to prevent this. Suggest you also consider an OWC SSD whilst there for the internal. It will be a huge improvement over the old drirve and OWC have videos on installing the drive.


https://eshop.macsales.com/shop/ssd/owc/imac-27-inch/2011

The SSD kit includes the tools and parts to do the install, with the over rider.

And the video:-


https://eshop.macsales.com/installvideos/imac_mid_2011/

 

[lute]

Plugged in a second flash drive and now the old Imac is up and running.
Many thanks for the advice and counsel!