Keysight N5221A/22A Service Guide 7-41Repair and Replacement ProceduresRemoving and Replacing the A29–A32 Test Port CouplersRemoving and Replacing the A29–A32 Test Port CouplersTools Required— T-10 TORX driver (torque to 9 in-lb or 1.02 N.m)— T-20 TORX driver (torque to 21 in-lb or 2.38 N.m)— 5/16 inch open-end torque wrench (torque to 10 in-lb or 1.13 N.m)— 1 inch open-end torque wrench (torque to 72 in-lb)— ESD grounding wrist strapRemoval ProcedureRefer to Figure 7-18 for this procedure.1. Disconnect the power cord.2. Remove the front panel assembly. Refer to “Removing and Replacing theFront Panel Assembly” on page 7-8.3. Position the analyzer bottom side up.4. On 4-port models, it is necessary to remove the couplers in pairs: ports1/3 and 2/4.5. Disconnect two semirigid cables (item ①) from each coupler to beremoved.6. Disconnect the wire harness (item ➁) from the corresponding front panelLED board and place it out of the way.7. Remove the coupler nut (item ③) from each coupler to be removed.8. Move the disconnected semirigid cables out of the way and remove thecoupler(s) from the analyzer. On 4-port models, separate the coupler pair.Replacement Procedure1. Reverse the order of the removal procedure.Adhere a new gap pad (4-port) or coupler bumper (2-port) (item ④) to thenew coupler in the same location as on the old one. Replace the vibrationmount (item ⑤) if necessary. Refer to “Bottom Hardware andMiscellaneous Parts” on page 6-98 for replacement part numbers.Torque all connectors to 10 in-lbs. Torque coupler nuts to 72 in-lbs.2. Perform the post-repair adjustments, verifications, and performance teststhat pertain to this removal procedure. Refer to Table 7-2 on page 7-60.Be careful not to damage the center pins of the semirigid cables. Someflexing of the cables is necessary to remove assemblies but do notover-bend them.
