Possible Hardware Fault Points & Repair Suggestions:

1. Relay Malfunction in Multiplex Module: Fault—Relays fail to close/stabilize; Repair—Test continuity with multimeter, replace faulty relay/module.
2. Damaged/Loose External Trigger Connections: Fault—Pins5(Channel Closed) or6(Channel Advance) of Ext Trig connector are loose/damaged; Repair—Inspect pins, re-seat or replace connector.
3. Built-in DMM Interference (External Instrument Use): Fault—Built-in DMM not disabled; Repair—Disable via menu (e.g., INST:DMM OFF command) as per user guide.
4. Poor Contact in Module Slots/COM Terminals: Fault—Multiplex module not seated properly or COM terminals loose; Repair—Reseat module, tighten COM connections.
5. Analog Bus Connection Issues: Fault—Faulty analog bus cables; Repair—Inspect and replace damaged cables.

Professional Support from 匠析生物: We offer repair, maintenance, and维保 solutions for Agilent 34980A and other brands (Thermofisher, Waters, etc.). Our services include relay replacement, connector repair, module troubleshooting, and regular cleaning/calibration. Contact us for expert help with your instrument issues.