Removing And Replacing The A18 System Motherboard - Keysight N5227A Service Manual

PNA Series Microwave Network Analyzers
N5227A

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
3. Remove the front panel assembly. Refer to
page 7-7.
4. Remove the A20 power supply. Refer to
page 7-16.
5. Remove the A21 CPU. Refer to
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
10. Remove the A19 midplane board. Refer to
7-14.
11. Remove the A4–A17 boards. Refer to
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
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
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.
Service Guide N5227-90001
Removing and Replacing the A18 System Motherboard
"Removing the Covers" on page
"Removing and Replacing the Front Panel Assembly" on
"Removing and Replacing the A20 Power Supply Assembly" on
"Removing and Replacing the A21 CPU Board Assembly" on page
"Removing and Replacing the A22 GPIB Board" on page
"Removing and Replacing the A19 Midplane Board" on page
"Removing and Replacing the A4–A17 Boards" on page
for steps 14 and 15.
Repair and Replacement Procedures
7-6.
7-20.
7-10.
"Removing and Replacing the
7-18.
7-11