
3-4-3
Search for video ROM failure
4-2-1
No timer tick
4-2-2
Shutdown failure
4-2-3
Gate A20 failure
4-2-4
Unexpected interrupt in protected mode
4-3-1
Memory failure above address 0FFFFh
4-3-3
Timer-chip counter 2 failure
4-3-4
Time-of-day clock stopped
4-4-1
Serial or parallel port test failure
4-4-2
Failure to decompress code to shadowed memory
4-4-3
Math-coprocessor test failure
4-4-4
Cache test failure
Diagnostic Lights
To help troubleshoot a problem, your computer has four lights labeled 1, 2, 3, and 4 on the bank panel. When the computer
starts normally, the lights flash before turning off. If the computer malfunctions, the sequence of the lights help to identify
the problem.
NOTE:
After the computer completes POST, all four lights turn off before booting to the operating system.
Light Pattern
Problem Description
Suggested Resolution
The computer is in a
normal
off
condition or
a possible pre-BIOS
failure has occurred.
The diagnostic lights
are not lit after the
computer successfully
boots to the operating
system.
Plug the computer into a working electrical outlet.
If the problem persists, contact Dell.
A possible processor
failure has occurred.
Reseat the processor (see Processor information for your computer).
If the problem persists, contact Dell.
Memory modules are
detected, but a memory
failure has occurred.
If two or more memory modules are installed, remove the modules, then
reinstall one module and restart the computer. If the computer starts
normally, continue to install additional memory modules (one at a time)
until you have identified a faulty module or reinstalled all modules
without error.
If available, install working memory of the same type into your
computer.
If the problem persists, contact Dell.
A possible graphics
card failure has
occurred.
Reseat any installed graphics cards.
If available, install a working graphics card into your computer.
If the problem persists, contact Dell .
A possible floppy drive
or hard drive failure
has occurred.
Reseat all power and data cables.
A possible USB failure
has occurred.
Reinstall all USB devices and check all cable connections.
Содержание OptiPlex 780
Страница 2: ......
Страница 26: ...7 Lift the hard drive and remove it from the system ...
Страница 29: ...4 Pull up on the drive release latch and then slide the floppy drive towards the back of the computer ...
Страница 30: ...5 Lift the floppy drive up and away from the computer ...
Страница 37: ...7 Release the processor power connector cable from routing guides under the system board ...
Страница 38: ...8 Remove the screws that secure the power supply to the back of the chassis ...
Страница 40: ...10 Lift the power supply up and away from the computer ...
Страница 43: ...4 Lift the fan and remove it from the computer ...
Страница 44: ...Replacing the Fan To replace the fan perform the above steps in reverse order Back to Contents Page ...
Страница 46: ...6 Disconnect the fan power cable 7 Disconnect the main power cable from the system board ...
Страница 47: ...8 Disconnect the IO panel cable ...
Страница 48: ...9 Disconnect the optical drive data cable from the system board ...
Страница 49: ...10 Disconnect the hard drive data cable from the system board ...
Страница 50: ...11 Disconnect the processor power cable ...
Страница 51: ...12 Remove the screws that secure the system board to the computer chassis ...
Страница 52: ...13 Remove the heat sink assembly bracket ...
Страница 56: ...4 Lift the drive release latch and then slide the drive towards the back of the computer ...
Страница 57: ...5 Lift and remove the drive from the computer ...
Страница 61: ...6 Lift the hard drive and remove it from the computer ...
Страница 64: ...4 Gently pull the riser cage handle and lift the riser cage up and away from the computer ...
Страница 65: ...5 On the riser cage rotate the card retention latch upward ...
Страница 69: ......
Страница 71: ...3 Rotate the heat sink upwards 4 Lift the heat sink and remove it from the computer ...
Страница 73: ...6 Lift the processor cover ...
Страница 74: ...7 Remove the processor from the computer ...
Страница 79: ...4 Gently rotate the IO panel away from the computer and then remove it from the computer ...
Страница 80: ...Replacing the IO Panel To replace the IO panel perform the above steps in reverse order Back to Contents Page ...