4 Calibration Procedures
112 Keysight 34970A/34972A Service Guide
(Optional) 34905/06A Relay Contact Resistance Verification
1 Be sure to read “Plug-in Module Test Considerations” on page 94.
2 Prepare the module by connecting an SMB short to CH10, CH11, CH12, and
CH13. Connect the COM1 terminal to the DMM. Be sure to use the correct
SMB connectors for the module.
3 Install the module in slot 100.
4 Close Channel 11.
5 Measure the resistance on the DMM.
6 Repeat steps 4 and 5 for Channels 12, 13, and 14.
7 Repeat steps 2, 3, 4, 5, and 6 for the channels connected to COM2.
Be sure to use the correct SMB connectors (50 W or 75 W).
In general, a new relay should have a contact resistance of less than 0.5 W.
Relays with contact resistance in excess of 1 W should be replaced.