• Corvalent Raptor ATX
• Chassis Plans ATXR-440B
• Corvalent FI-RBXAX
• Supermicro (unknown)

• DALLAS RTC coin cell empty

The motherboard's Real-Time Clock (RTC) chip contains a coin cell that may have drained, causing the loss of CMOS settings. This can result in an inability to save settings, causing system instability or failure to boot. To fix this, the RTC chip can be replaced with an equivalent or repaired by cutting into it and soldering on a new external coin cell holder. Replacement guides are available at https://github.com/necroware/nwX287 or https://github.com/necroware/nw12887, depending on the actual chip used.

For some rather bizzarre reason, the integrated RTC in the PIIX4E chipset is unused and it has an external Dallas DS12887A clock with non-replaceable battery. The board has a built-in 7-segment display for POST codes.