Keysight N5227A - Removing and Replacing the A18 System Motherboard

Service Guide N5227-90001 7-11
PNA Series Microwave Network Analyzers Repair and Replacement Procedures
N5227A Removing and Replacing the A18 System Motherboard
Removing and Replacing the A18 System Motherboard
Tools 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)
• 5/8 inch nutsetter (torque to 21 in-lb or 2.38 N.m)
• ESD grounding wrist strap
Removal Procedure
1. Disconnect the power cord.
2. Remove the outer and inner covers. Refer to “Removing the Covers” on page 7-6.
3. Remove the front panel assembly. Refer to “Removing and Replacing the Front Panel Assembly” on
page 7-7.
4. Remove the A20 power supply. Refer to “Removing and Replacing the A20 Power Supply Assembly” on
page 7-16.
5. Remove the A21 CPU. Refer to “Removing and Replacing the A21 CPU Board Assembly” on page 7-18.
6. Disconnect the rear panel cables.
7. Remove the threaded hardware from the rear panel.
8. Remove the rear panel.
9. Remove the A22 GPIB board. Refer to “Removing and Replacing the A22 GPIB Board” on page 7-20.
10. Remove the A19 midplane board. Refer to “Removing and Replacing the A19 Midplane Board” on page
7-14.
11. Remove the A4–A17 boards. Refer to “Removing and Replacing the A4–A17 Boards” on page 7-10.
12. Remove the right side and left side fan brackets. Disconnect the right fan wire and the left fan wire from
the A18 System Motherboard, and then remove the fan brackets. Refer to “Removing and Replacing the
Fans” on page 7-50.
13. Turn the analyzer over so that the bottom side is up and remove the A23 Test Set Motherboard and the
A24 IF Mux. Disconnect the two ribbon cables from the A18 System Motherboard.
Refer to Figure 6-37 on page 6-79 for steps 14 and 15.
14. Remove four screws (item A) that secure the bottom of the midplane bracket to the chassis.
15. Remove seven screws (item B) that secure the left side inner bracket to the chassis.
Refer to Figure 7-1 for the remaining steps in this procedure.
16. Turn the analyzer back over so that the top side is up. Remove two screws (item ①) from each side that
secure the midplane bracket to the chassis inner panels. Lift the midplane bracket out of the analyzer.