HP Z400 HP Z400 Workstation Maintenance and Service Guide - Page 178

Table 6-8 Diagnostic lights and audible codes (continued) Activity Possible cause Recommended action Red Power LED blinks two times, once every second, followed by a two-second pause. Two beeps. CPU thermal protection activated by either of the following methods: 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. ● A fan might be blocked 1. Ensure that the workstation air vents are not blocked and the cooling or not turning. fan is running. ● The heatsink and fan 2. Open the access panel, press power button, and verify that the CPU assembly is not fan is spinning. If the CPU fan is not spinning, make sure the fan properly attached to the cable is plugged into the workstation board header. Ensure the fan CPU. 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. Red Power LED blinks three times, once every second, followed by a two-second pause. Three beeps. CPU not installed (not an indicator of bad CPU). 1. Verify that the CPU is present. 2. Reseat the CPU. Red Power LED blinks four times, once every second, followed by a two-second pause. Four beeps. Power failure (power supply CAUTION: Internal components might be powered even when the is overloaded) 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 (24pin 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** LED lights, the power 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** LED does not light, the problem might be in the power supply. Contact HP for assistance. Red Power LED blinks five times, once every second, followed by a two-second pause. Five beeps. Pre-video memory error 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. 166 Chapter 6 Diagnostics and troubleshooting ENWW