7-18 Keysight N5221A/22A Service GuideRepair and Replacement ProceduresRemoving and Replacing the A14 System Motherboard7-Removing and Replacing the A14 System MotherboardTools 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 2.38N.m)— 5/16 inch open-end torque wrench (torque to 10 in-lb or 1.13 N.m)— ESD grounding wrist strapRemoval ProcedureRefer to Figure 7-7 for this procedure.1. Disconnect the power cord.2. Remove the outer and inner covers. Refer to “Removing the Covers” onpage 7-6.3. Remove the front panel assembly. Refer to “Removing and Replacing theFront Panel Assembly” on page 7-8.4. Remove the A18 GPIB board. Refer to “Removing and Replacing the A18GPIB Board” on page 7-27.5. Remove the A15 midplane board. Refer to “Removing and Replacing theA15 Midplane Board” on page 7-21.6. Remove the A4–A13 boards. Refer to “Removing and Replacing the A4–A13 Boards” on page 7-15.7. Remove the fan bracket and fans. Refer to “Removing and Replacing theFans” on page 7-56.8. Turn the analyzer over so that the bottom side is up and remove fourscrews (item ①), that secure the bottom of the midplane bracket to thechassis.9. Turn the analyzer back over so that the top side is up. Remove sevenscrews (item ➁) that secure the left side bracket to the chassis left innerpanel.10.Remove two screws (item ③) from each side that secure the midplanebracket to the chassis left and right inner panels. Lift the midplane bracketout of the analyzer.11.Remove three screws (item ④) that secure the A14 system motherboardto the chassis.12.Slide the A14 system motherboard toward the rear of the analyzer torelease it from the 15 keyhole standoffs (item ⑤) on the chassis.13.Lift the A14 system motherboard just enough to unplug the ribbon cablefrom the bottom side, then lift it out of the analyzer.
