Acer 390 Series, Service Manual

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1-28 Service Guide
HARD DISK STANDBY MODE
The hard disk enters standby mode when there are no disk read/write operations within the period
of time determined by the computer’s HPM unit. In this state, the power supplied to the hard disk is
reduced to a minimum. The hard disk returns to normal once the computer accesses it.
Table 1-35 Hard Disk Standby Mode Conditions and Descriptions
Condition Description
The condition to enter HDD Standby
Mode Display Standby HPM timer times-out or LCD cover is
closed.
The condition of HDD Standby Mode All the system components are on except HDD spindle
motor
The condition back to On Mode Any access to HDD
BATTERY LOW
When the battery capacity is low and no adapter is plugged in, the system will generate the
following battery low warning:
•
Flash power LED with 1 Hz.
•
Issue 4 short beeps per minute (if enabled in setup).
•
If the AC adapter does not plug in within 3 minutes and the “Standby/Hibernation upon
Battery-low” in BIOS SETUP is enabled, the system will enter Standby/0-Volt Hibernation
Mode. The battery low warning will stop as soon as the AC adapter is plugged into the
system.
THE AUTODIM PROCESS OF THE LCD BRIGHTNESS
The notebook has a unique “automatic dim” power saving feature. When the notebook is using
AC power and you disconnect the AC adapter from the notebook, the system “decides” whether or
not to automatically dim the LCD backlight to save power.
If the LCD backlight is too bright, the system automatically adjusts it to a manageable level;
otherwise, the level stays the same. If you want a brighter picture, you can then adjust the
brightness and contrast level using hotkeys (Fn-F2).
If you reconnect AC power to the system, the system automatically adjusts the LCD backlight to its
original level — the brightness and contrast level before disconnecting the AC adapter. If you
adjusted the brightness and contrast level after disconnecting AC power, the level stays the same
after you reconnect the AC adapter.
There are two reasons for the notebook to have the LCD AutoDim feature. The first is to save the
power during the notebook is operating under the DC mode. The second is to save the “favorite”
brightness parameter set by the user.