The LNR7634 is the main control (CSBC) board used in GE Lunar DEXA bone densitometry systems, handling signal processing and communication with the patient interface and imaging modules. Common failure points for this class of medical imaging boards include degraded power supply rails, failed surface‑mount capacitors or inductors on the high‑current paths, and broken trace connections due to vibration or thermal cycling. Begin troubleshooting by verifying that all input voltages (12 V, 5 V, and isolated reference lines) are within spec with a calibrated multimeter; check for visible signs of component damage such as burn marks, bulging caps, or cracked solder joints; and review any error codes logged in the system’s diagnostic console to pinpoint affected subsystems.[oss-gpt-20b]