DiGiCo D‑Rack is a floor‑mounted digital stage box that supplies 32 XLR microphone inputs, 8 standard line outputs and an 8‑slot expansion for either analogue or AES/EBU signals, all routed via a single CAT5E cable to the SD‑Series console. Common failure points in this class include power supply module overheating, front‑panel input jack wear, and firmware corruption causing loss of I/O channels; check the unit’s internal temperature and verify firmware version against the latest release. First‑check diagnostics: confirm 48 V phantom power is present on all mic inputs, inspect the CAT5E cable for continuity and proper termination, and review any console error logs for “D‑Rack channel missing” or “I/O link failure” messages.[oss-gpt-20b]