Dell OptiPlex 990 Desktop Service Manual page 76

Problem Description
Troubleshooting Steps Remove all peripheral cards from the PCI and PCI-E slots and
LED
Power Button
Problem Description
Troubleshooting Steps Re-seat the 2x2 power connector from the power supply unit.
LED
Power Button
Problem Description
Troubleshooting Steps Remove all peripheral cards from the PCI and PCI-E slots and
LED
Power Button
Problem Description
Troubleshooting Steps
76
A possible system board failure has occurred.
re-start the computer. If the computer boots, add the
peripheral cards back one by one until you find the bad one.
Power connector not installed properly.
Possible peripheral card or system board failure has occurred.
re-start the computer. If the computer boots, add the
peripheral cards back one by one until you find the bad one.
A possible system board failure has occurred.
– 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.