Dell OptiPlex 790 (Early 2011) - Manual (Page 68)

add the peripheral cards back one by one until you find
the bad one.
LED
Power Button
Problem Description Power connector not installed properly.
Troubleshooting Steps Re-seat the 2x2 power connector from the power
supply unit.
LED
Power Button
Problem Description Possible peripheral card or system board failure has
occurred.
Troubleshooting
Steps
Remove all peripheral cards from the PCI and PCI-E
slots and re-start the computer. If the computer boots,
add the peripheral cards back one by one until you find
the bad one.
LED
Power Button
Problem Description A possible system board failure has occurred.
Troubleshooting
Steps
• Disconnect all internal and external peripherals,
and re-start the computer. If the computer boots,
add the peripheral cards back one by one until you
find the bad one.
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