there is no HP 1 beep code, there is however a 3 beep with i sec between beeps, which indicates a cpu error
https://support.hp.com/us-en/document/c01733543
The Diagnostic LED blinks red 3 times and the system beeps 3 times (once per second), then a 2-second pause follows:
This indicates that the processor is not installed.
To resolve the issue, complete the following steps:
1) Install the processor.
2) Reseat the processor.
3) If the issue persists, replace the processor.
The Diagnostic LED blinks red 4 times and the system beeps 4 times (once per second), then a 2-second pause follows.
This indicates power failure.
To resolve the issue, complete the following steps:
1) Open the access panel, and ensure that the necessary power supply cables are connected to the system board.
2) Locate a faulty device by removing all devices, and then reinstalling one at a time until the workstation fails:
- Disconnect AC power to the workstation.
- Remove all the devices.
- Reinstall a device.
- Reconnect AC power.
- Continue adding devices to ensure that all devices are functioning properly.
- Replace the device causing the failure.
- Remove all the devices.
- Reinstall a device.
- Reconnect AC power.
- Continue adding devices to ensure that all devices are functioning properly.
- Replace the device causing the failure.
3) Verify the power supply functionality.
- Disconnect AC power.
- Z400: Remove all internal power supply cables from the system board.
- Z600 & Z800: Remove the Power Supply from the chassis
- Plug in AC power.
- Z400: Remove all internal power supply cables from the system board.
- Z600 & Z800: Remove the Power Supply from the chassis
- Plug in AC power.
If the power supply fan spins, and the LED illuminates, then the power supply is good. Replace the system board.
If the power supply fan does not spin, or the LED does not illuminate, then replace the power supply.
If the power supply fan does not spin, or the LED does not illuminate, then replace the power supply.
The Diagnostic LED blinks red 5 times and the system beeps 5 times (once per second), then a 2-second pause follows:
This indicates a pre-video memory error.
To resolve the issue, complete the following steps:
1) Ensure that the memory modules are loaded correctly.
2) Reseat the memory modules.
3) Replace the memory modules one at a time to find the faulty module.
4) Replace the third-party modules with HP memory.
5) Replace the system board.