ETCnomad Puck is displaying the error "Bad RTC" while powering on.
This error signifies that the BIOS is reporting a Bad Real Time Clock reading.
This is often caused by the coin cell battery dying or not providing enough charge for the BIOS to keep its internal clock running when the unit is powered off.
Recommendation to resolve this issue is to replace the coin cell battery in the Puck.
The exact model number for this battery is CR2032W.
This is a 2032 Coin Cell battery that is pre-wired.
See the image below pointing out where it is located, underneath the SSD.