Apple 2009 iMac - Page 98

iMac (21.5-inch, Late 2009) Symptom Charts — Mechanical 98
2010-11-18
Fan Failures / Thermal Issues
Unlikely cause: speakers
Quick Check
Symptoms Quick Check
Fan Failures / Thermal Issues
• System feels very hot
• Fan(s) not operating
• Fan(s) running fast
• System is noisy
1. Verify that vents on bottom and back of system
are free of dust and other obstructions that might
inhibit proper airow through the system.
2. Verify that computer is not exposed to direct
sunlight which may heat up enclosure, making it
feel hot to the touch.
3. Verify computer is not running hotter than
expected for normal operation. If possible,
compare to a similarly congured system. Note:
Power supply is located in upper left corner
where highest temperatures can usually be felt.
4. Launch Applications/Utilities/Activity Monitor.
Verify if an application or process is consuming
a high percentage of CPU bandwidth. CPU-
intensive applications can cause fans to run
fast in order to maintain proper internal system
temperatures. If needed, quit the application or
restart the system to resolve issue.
5. Reset SMC by unplugging power cord for ~15
seconds.
Deep Dive
Check Result Action Code
1. Run Apple System Diagnostic.
Verify if ASD generates one or
more errors.
Yes
Suspect possible fan or sensor
error. Go to ASD Error Codes
table to decode error. Follow
instructions in table for
resolving error, then retest.
No Go to step 2.
2. Verify if noise sounds like one
or more fans running faster
than expected.
Yes Fans running fast. Reset SMC
by disconnecting power cord
for ~15 seconds then retest. If
issue continues go to step 3.
No Go to step 3.