Apple MD094LL/A manual Power-related system shut downs

3) Power-related system shut downs:

•External power source was removed.

Power-related shut downs are due to power management, poor connections, or defective power sources.

Suggested steps for troubleshooting are :

•Reset the SMC: Refer to: kBase #HT3964: Intel-based iMac: How to reset the System

Management Controller

•Verify the following cables are securely connected: AC power cable, AC inlet, and DC power supply cable connections to logic board

4)Hardware-related system shut downs:

•One of the temperature sensors reached a specified temperature limit

•One of the voltage sensors reached a specified voltage limit

•One of the current sensors reached a specified current limit

These shut downs are due to temperature, voltage, current, fan speed or other hardware related sensor values getting out of range.

Suggested steps for troubleshooting are :

•Check for all sensors connections and values using the latest available Apple service utilities and locate sensors using table in the General Troubleshooting chapter

•Check /listen for fan(s) operation

•Check cleanliness of the heatsink fins and the air flow,

•Check for correct seating of the heatsink on logic board and presence of thermal material.

For additional information refer to the Intermittant Shutdown table on the next page.

2010-09-09 iMac (27-inch, Mid 2010) Symptom Charts — Startup and Power  40