TAJIMA 77N 3F245A Switch Card is an industrial control board used in Tajima embroidery and textile machinery to route power, signal, and communication between the main controller and peripheral modules. Common failure modes on similar switch cards include burnt or cracked solder joints, failed MOSFETs or relays, and degraded PCB traces from long‑term vibration or thermal cycling; these can manifest as intermittent loss of I/O, abnormal voltage readings, or error codes in the host system. First‑check diagnostics: verify that the card receives its rated supply voltage (typically 24 V DC) and confirm continuity across all power rails; inspect for visual signs of arcing, discoloration, or component damage; then check the status LEDs or diagnostic outputs on the host controller to isolate whether the fault originates on the card itself or in upstream cabling.[oss-gpt-20b]