E8257D/67D, E8663D PSG Signal Generators Service Guide 395
Assembly Replacement
AT1 90 dB Attenuator (Option 1EM)
AT1 90 dB Attenuator (Option 1EM)
Tools Required
— T–10 driver
— 5/16” open–ended wrench
Removal Procedure
Refer to Figure 3-75 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. Disconnect the AT1W1 ribbon cable from A26J13.
5. Using the 5/16” open–ended wrench, disconnect the W81 and W94 RF
cables from the AT1 90 dB Attenuator.
6. Using the T–10 driver, remove the two screws that attach the AT1 90 dB
Attenuator to the side panel.
7. Remove the AT1 90 dB Attenuator.
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 W81 and W94 are easily damaged. DO NOT bend them. Bending the
cables can damage the center conductor, which could result in power "holes".