The Lunar DEXA CSBC Circuit Board (model LNR‑7635/LU40814) is the central control and signal‑processing board in GE Lunar bone densitometers, handling scan data acquisition, image reconstruction, and communication with the user interface. Common failure points include burnt or cracked power input traces, degraded ICs such as the microcontroller or DSP, and damaged connectors to the detector module; these often manifest as intermittent operation, error codes related to “CSBC” or complete loss of imaging capability. Begin troubleshooting by verifying the board’s 12 V/5 V supply rails with a multimeter, inspecting for burn marks or loose solder joints, and checking all connector pins for continuity before reviewing the system log for CSBC‑specific fault codes.[oss-gpt-20b]