Assembly Replacement
A31 Motherboard
2-70
A31 Motherboard
Tools Required
• T-10 driver
• 5/16” open ended wrench
• needle-nose plier
Removal Procedure
Refer to Figure 2-34 for this procedure.
1. Disconnect the power cord.
2. Remove the covers from the signal generator. Refer to "Outer Instrument Cover" on page 2-4 and
"Inner Instrument Cover" on page 2-6.
3. Position the signal generator with the A31 Motherboard facing you and the RF deck on top.
4. Remove the front panel. Refer to "Front Panel" on page 2-8.
5. Remove the assemblies that are inserted into the A31 Motherboard. Refer to "A5 Sampler" on page 2-20, "A9 YIG
Driver" on page 2-28, "A10 ALC" on page 2-31, "A11 Pulse/Analog Modulation Generator" on page 2-33, and "A18
CPU" on page 2-35.
6. Disconnect the W37 RF cable from the A23 Low Band Coupler/Detector.
7. Disconnect the W39 and W40 RF cables from the A29 20 GHz Doubler J4 and J3.
8. Disconnect the W10, W11, W21, and W22 flexible cables from the A31 Motherboard J1031, J1021, J1043, and J1042.
9. Using the T-10 driver, remove the 15 screws (1) that hold the A31 Motherboard to the chassis.
10. Disconnect the W35 ribbon cable from the A26 MID.
11. Disconnect the W23 ribbon cable from the A21 Rear Panel Interface while removing the A31 Motherboard from the
chassis.
Replacement Procedure
• Reverse the order of the removal procedure.
• Torque all T-10 screws to 9 in-lbs.
• Torque all RF connectors to 8 in-lbs.
• Perform the post-repair adjustments and performance tests that pertain to this removal procedure.