E8257D/67D, E8663D PSG Signal Generators Service Guide 393
Assembly Replacement
AT1 115 dB Attenuator
AT1 115 dB Attenuator
Tools Required
— T–10 driver
— 5/16” open–ended wrench
Removal Procedure
Refer to Figure 3-74 for this procedure.
1. Disconnect the power cord.
2. Remove the covers from the signal generator. Refer to “Outer Instrument
Cover” on page 258 and “Inner Instrument Cover” on page 260.
3. Position the signal generator with the A31 Motherboard facing you so that
the RF deck is on top.
4. Using the 5/16” open-ended wrench, disconnect the following RF cables
according to the signal generator you have.
Option 513, 520, 532, 540, 544 or E8257N: Disconnect W24 and W25 from
the AT1 115 dB Attenuator.
Option 521: Disconnect W143 and W145 from the AT1 115 dB Attenuator.
5. Using the T–10 driver, remove the two screws (1) that attach the AT1
115 dB Attenuator to the side panel.
6. Disconnect the AT1W1 ribbon cable from A26J13.
7. Remove the attenuator from the A26 MID bracket.
8. Using the T–10 driver, remove the sheet metal from the attenuator.
Replacement Procedure
1. Reverse the order of the removal procedure.
2. Torque all T–10 screws to 9 in–lbs.
3. Torque all RF connectors to 8 in–lbs.
4. Perform the post–repair adjustments and performance tests that pertain
to this removal procedure.
Cables W24, W25, W143, and W145 are easily damaged. DO NOT bend them.
Bending the cables can damage the center conductor, which could result in
power “holes”.
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