iMac (27-inch, Mid 2010) Symptom Charts — Mechanical 121
2010-09-09
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.
6. Run latest available Apple service utilities.
Deep Dive
Check Result Action Code
1. Run latest available Apple
service utilities and. Verify if one
or more errors are reported.
Yes Suspect possible fan or
sensor error. Go to ASD Error
Codes table and sensors
location table (in General
Troubleshooting) to decode
error. Follow instructions in
table for resolving error, then
retest.
No Go to step 2.