white imac fix
My 20" 2.16 GHz Intel Core 2 Duo had become almost useless due to freezes and crashes- with NO crash reports in the logs.
They were often preceeded by video glitches, so I assumed it was a bad video card- unfortunately soldered to mother board.
Apparently, from forum postings, this is not an uncommon problem. The computer would run longer if the day was cooler, but rarely more than 10 minutes, so I suspected it was aggravated by heat.
Then I found this post from Bodomann on an Apple Support forum:
"Following up on my previous posting regarding my son's late model 2006 iMac that required a $900 logic board replacement:
Turns out the problem is apparently related to a bad CPU temp sensor. I installed 'iMac Fan Control' (Google it) which reported the CPU temp always at 32 degrees Fahrenheit (obviously incorrect). The same software allowed me to adjust the CPU fan manually. After multiple trials I set the CPU speed to 2800RPM after which the system would run forever - never freezing with the dreaded grey box 'reboot me' screen. I tried several times reverting the software to default speeds and the system would always crash within 10 minutes. "
I downloaded free Fan Control 1.2 for Imac from Derman Enterprises (they have an Intel iMac and a Mac Book/Pro version). It installs as a system preferences control panel. I cranked up all three fan speeds. The fans sped up noticeably. Horizontal lines have gone from screen (so far), no color artifacts and no crashes yet. I may have a real computer back! Hope Apple checks this out-
The control panel also gives the temps sensors are reporting at the CPU, hard drive and DVD drive. The CPU sensor reports the CPU temp as 32 degrees F- which is clearly wrong, unless Apple has been installing little refrigerators inside.
So thanks to Bodomann for posting- Hats off and three cheers to Derman and Cristoph for source code.
http://www.derman.com/iMac-Fan-Control
http://www.lobotomo.com/products/FanControl/index.html
My 20" 2.16 GHz Intel Core 2 Duo had become almost useless due to freezes and crashes- with NO crash reports in the logs.
They were often preceeded by video glitches, so I assumed it was a bad video card- unfortunately soldered to mother board.
Apparently, from forum postings, this is not an uncommon problem. The computer would run longer if the day was cooler, but rarely more than 10 minutes, so I suspected it was aggravated by heat.
Then I found this post from Bodomann on an Apple Support forum:
"Following up on my previous posting regarding my son's late model 2006 iMac that required a $900 logic board replacement:
Turns out the problem is apparently related to a bad CPU temp sensor. I installed 'iMac Fan Control' (Google it) which reported the CPU temp always at 32 degrees Fahrenheit (obviously incorrect). The same software allowed me to adjust the CPU fan manually. After multiple trials I set the CPU speed to 2800RPM after which the system would run forever - never freezing with the dreaded grey box 'reboot me' screen. I tried several times reverting the software to default speeds and the system would always crash within 10 minutes. "
I downloaded free Fan Control 1.2 for Imac from Derman Enterprises (they have an Intel iMac and a Mac Book/Pro version). It installs as a system preferences control panel. I cranked up all three fan speeds. The fans sped up noticeably. Horizontal lines have gone from screen (so far), no color artifacts and no crashes yet. I may have a real computer back! Hope Apple checks this out-
The control panel also gives the temps sensors are reporting at the CPU, hard drive and DVD drive. The CPU sensor reports the CPU temp as 32 degrees F- which is clearly wrong, unless Apple has been installing little refrigerators inside.
So thanks to Bodomann for posting- Hats off and three cheers to Derman and Cristoph for source code.
http://www.derman.com/iMac-Fan-Control
http://www.lobotomo.com/products/FanControl/index.html