HP Z400 - Workstation Maintenance And Service Manual page 178

Table 6-8 Diagnostic lights and audible codes (continued)
Activity
Red Power LED blinks two
times, once every second,
followed by a two-second
pause. Two beeps.
Red Power LED blinks three
times, once every second,
followed by a two-second
pause. Three beeps.
Red Power LED blinks four
times, once every second,
followed by a two-second
pause. Four beeps.
Red Power LED blinks five
times, once every second,
followed by a two-second
pause. Five beeps.
166 Chapter 6 Diagnostics and troubleshooting
Possible cause
CPU thermal protection
activated by either of the
following methods:
● A fan might be blocked
or not turning.
● The heatsink and fan
assembly is not
properly attached to the
CPU.
CPU not installed (not an
indicator of bad CPU).
Power failure (power supply
is overloaded)
Pre-video memory error
Recommended action
CAUTION: Internal components might be powered even when the
workstation is off. To prevent damage, disconnect the workstation power
cord before you remove a component.
1. Ensure that the workstation air vents are not blocked and the cooling
fan is running.
2. Open the access panel, press power button, and verify that the CPU
fan is spinning. If the CPU fan is not spinning, make sure the fan
cable is plugged into the workstation board header. Ensure the fan
is fully and properly seated or installed.
3. If fan is plugged in and seated properly, but is not spinning, the
problem might be in the CPU fan. Contact HP for assistance.
4. Verify that the fan assembly is properly attached. If problems persist,
there might be a problem with the CPU heatsink. Contact HP for
assistance.
1. Verify that the CPU is present.
2. Reseat the CPU.
CAUTION: Internal components might be powered even when the
workstation is off. To prevent damage, disconnect the workstation power
cord before you remove a component.
1. Open the access panel and ensure that all power connections (24-
pin Main, 4-pin CPU) are secure on the system board.
2. Check if a device is causing the problem by removing all attached
devices (such as hard, diskette, or optical disk drives, and expansion
cards.) Power on the workstation. If the system enters the POST,
power off and replace one device at a time; repeat this procedure
until failure occurs. Replace the device that is causing the failure.
Continue adding devices one at a time to ensure all devices are
functioning properly.
3. Check the power supply functionality.
a. Disconnect the AC power.
b. Disconnect ALL internal power supply cables.
c. Plug in the AC power.
If the power supply fan spins and the BIST
supply is functional. The problem might be on the system board.
Contact HP for assistance.
If the power supply fan does not spin or the BIST
light, the problem might be in the power supply. Contact HP for
assistance.
CAUTION: Internal components might be powered even when the
workstation is off. To prevent damage, disconnect the workstation power
cord before you remove a component.
1. Reseat DIMMs.
2. Replace DIMMs one at a time to isolate faulty module.
3. Replace third-party memory with HP memory.
4. The problem might be on the system board. Contact HP for
assistance.
** LED lights, the power
** LED does not
ENWW