E8257D/67D, E8663D PSG Signal Generators Service Guide
Assembly Replacement
A31 Motherboard (E8257D & E8663D)
3-84
A31 Motherboard (E8257D & E8663D)
Tools Required
• T–10 driver
• 5/16” open–ended wrench
• needle–nose pliers
Removal Procedure
Refer to Figure 3- 52 for this procedure.
1. Disconnect the power cord.
2. Remove the covers from the signal generator. Refer to “Outer Instrument Cover” on page 3- 4 and “Inner
Instrument Cover” on page 3- 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 3- 8.
5. Remove the assemblies that are inserted into the A31 Motherboard. Refer to “A5 Sampler, A6 Frac–N, A7
Reference (Standard and Option UNR/UNX/UNY), A8 Output, A45 Frac- N and A46 Offset” on page 3- 23, “A9 YIG
Driver” on page 3- 24, “A10 ALC” on page 3- 26, “A11 Pulse/Analog Modulation Generator” on page 3- 28, “A14
Baseband Generator (E8267D Only)” on page 3- 36, “A18 CPU” on page 3- 40, and “A13 I/Q MUX (E8267D Standard
or with Option 015) (Serial Prefixes <US4722/MY4722)” on page 3- 32.
6. Using the 5/16” open–ended wrench, disconnect the following RF cables:
• W40 from A29J3
• W39 from A29J4
• W37 from the A23 Lowband Coupler/Detector
• W137 from W121
7. Using the needle–nose pliers, disconnect the following flexible cables:
• W21 from A31J1043
• W10 from A31J1031
• W11 from A31J1021
• W54 from A31J1032
• W47 from A31J1041
• W22 from A31J1042
8. Using needle- nose pliers, disconnect W138 from the A31 Motherboard.
9. Disconnect the W23 ribbon cable from the A21 Rear Panel Interface while removing the
A31 Motherboard from the chassis.
10. Disconnect the W35 ribbon cable from the A26 MID J10.
11. Disconnect the W135 cable from A31P242 (Option 521 only).
12. Using the T–10 driver, remove the 15 screws (1) that hold the A31 Motherboard to the chassis.
Replacement Procedure
1. Reverse the order of the removal procedure.
2. Send command: DIAG:FILE:BACK, this copies data to the Motherboard.
3. Torque all T–10 screws to 9 in–lbs.
4. Torque all RF connectors to 8 in–lbs.
5. Perform the post–repair adjustments and performance tests that pertain to this removal procedure.
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