From fit-PC wiki
1. Fit-PC2 BIOS reset:
- Power down the PC and unplug the power cable.
- Open the service door and remove the storage.
- Open the top cover gently after removing 4 bolts.
- Reset the BIOS by shorting two test points of J4B2 for 3 seconds, located in the corner (near one memory chip and power button).
- Close the cover, return the storage and the service door.
- Plug the power and power up the PC (either auto-on or pressing power button).
2. Try to answer the following questions:
- Are you able to power up without storage?
- What type of storage being used in terms of RPM (in case of HDD)?
- Note that 7200rpm drives are not recommended due to lower power nature of the PC, as such drives used to overload the machine. 5400rpm drives at maximum must be used.
3. Power supply:
- 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.