ビデオカードの交換とケース内部の清掃が終了. 以下のようなxorg.confで正常に動作している…
Section "ServerLayout"
Identifier "X.org Configured"
Screen 0 "Screen0" 0 0
InputDevice "Mouse0" "CorePointer"
InputDevice "Keyboard0" "CoreKeyboard"
EndSection
Section "Files"
RgbPath "/usr/local/lib/X11/rgb"
ModulePath "/usr/local/lib/xorg/modules"
FontPath "/usr/local/lib/X11/fonts/URW/"
FontPath "/usr/local/lib/X11/fonts/Type1/"
FontPath "/usr/local/lib/X11/fonts/TrueType/"
FontPath "/usr/local/lib/X11/fonts/TTF/"
FontPath "/usr/local/lib/X11/fonts/OTF/"
FontPath "/usr/local/lib/X11/fonts/terminus-font/"
FontPath "/usr/local/lib/X11/fonts/bitstream-vera/"
FontPath "/usr/local/lib/X11/fonts/local/"
FontPath "/usr/local/lib/X11/fonts/misc/"
FontPath "/usr/local/lib/X11/fonts/75dpi/"
FontPath "/usr/local/lib/X11/fonts/100dpi/"
FontPath "/usr/local/lib/X11/fonts/cyrillic/"
EndSection
Section "Module"
Load "extmod"
Load "record"
Load "dbe"
Load "glx"
Load "xtrap"
Load "GLcore"
Load "dri"
Load "freetype"
Load "type1"
EndSection
Section "InputDevice"
Identifier "Keyboard0"
Driver "keyboard"
Option "XkbModel" "pc101"
Option "XkbLayout" "us"
EndSection
Section "InputDevice"
Identifier "Mouse0"
Driver "mouse"
Option "Protocol" "auto"
Option "Device" "/dev/sysmouse"
EndSection
Section "Monitor"
Identifier "Monitor0"
VendorName "MEL"
ModelName "RDT176S"
HorizSync 31.5 - 69.0
VertRefresh 56.0 - 75.0
Option "DPMS"
EndSection
Section "Device"
Identifier "Card0"
Driver "ati"
VendorName "ATI Technologies Inc"
BoardName "RV350 AS [Radeon 9550]"
BusID "PCI:1:0:0"
EndSection
Section "Screen"
Identifier "Screen0"
Device "Card0"
Monitor "Monitor0"
DefaultDepth 24
SubSectionSub "Display"
Depth 24
Modes "1280x1024"
EndSubSection
EndSection
Section "DRI"
Mode 666
EndSection