From fit-PC wiki
1. Airtop BIOS reset:
- Power down the PC and unplug the power cable.
- Open the service door.
- Remove the disks cartridge.
- Reset the BIOS by pressing the low profile push button SW4 (RTC_RST).
- Mount the disks cartridge and close the door.
- Plug the power and power up the PC (either auto-on or pressing power button).
2. Check memory (RAM):
- Verify RAM modules are installed. The system will not boot without it.
3. Check storage (HDD/SSD):
- Verify power up without storage. Sometimes damaged drives may cause the overall system to malfunction.
4. Check power supply (PSU):
- Verify the power supply is not damaged and functions properly.
- If you have another power supply use it to eliminate and determine the failing side.
- In case you use other power supply make sure it provides uninterrupted power and stable grounding.