Apple Mac Pro - Page 32

Mac Pro (Mid 2010) General Troubleshooting — Power-On Self Test: RAM and Processor Verication 32
2010-08-31
Real Time Clock (RTC) Reset
The Real Time Clock (RTC) is a chip on the backplane board that controls the date and time
functions of the computer. Resetting the RTC may resolve booting issues.
1. From the Apple menu, choose Shut Down (or if the computer is not responding, hold the
power button until it turns o).
2. Unplug the AC power cord.
3. Remove the battery for at least 20 seconds. You may need to remove a PCI Express card to
have access to the battery.
Alternatively, you can use the RTC reset button (small button located next to the battery). Press
the button for one second when the computer is shut down but still connected to AC power.
Power-On Self Test: RAM and Processor Verication
When the computer is started up after being fully shut down, a self test in the computer’s ROM
is automatically run. (The test is not run if the computer is only restarted.) If the test detects a
problem, the status LED (located above the power button on the front of the computer) ashes
in the following ways*:
• 1 Flash: No RAM is installed or detected or the quick memory test failed. An LED will light up
on the processor board next to the aected DIMM or empty DIMM slot.
• 3 Flashes: A RAM bank failed extended memory testing. An LED will light up on the
processor board corresponding to the aected DIMM.
Troubleshooting: Try reseating the memory DIMMs. Check memory installation instructions for
proper installation order. Swap aected DIMM with known good DIMM.
*Note: The status LED lights up when the power button is depressed at startup. Do not count
this light as one of the diagnostic ashes. The memory processor board diagnostic LEDs also
ash briey startup and shut down and when the computer goes in and out of sleep mode.
This is normal behavior.