E8257D/67D, E8663D PSG Signal Generators Service Guide 397Assembly ReplacementAT1 115 dB Attenuator (Option 1EM)AT1 115 dB Attenuator (Option 1EM)Tools Required— T–10 driver— 5/16” open–ended wrenchRemoval ProcedureRefer to Figure 3-76 for this procedure.1. Disconnect the power cord.2. Remove the covers from the signal generator. Refer to “Outer InstrumentCover” on page 258 and “Inner Instrument Cover” on page 260.3. Position the signal generator with the A31 Motherboard facing you so thatthe RF deck is on top.4. Disconnect the AT1W1 ribbon cable from A26J13.5. Using the 5/16” open–ended wrench, disconnect the following RF cablesaccording to the signal generator you have.Options 503, 509, 513, 520, and 540: Disconnect the W72 and W73 RFcables from the AT1 115 dB Attenuator.Option 521: Disconnect the W146 and W147 RF cables from the AT1115 dB AttenuatorOptions 532 and 544: Disconnect the W93 and W85 RF cables from theAT1 115 dB Attenuator.6. Using the T–10 driver, remove the two screws that attach the AT1 115 dBAttenuator to the side panel.7. Remove the AT1 115 dB Attenuator.8. Using the T–10 driver, remove the sheet metal from the attenuator.Replacement Procedure1. 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.Cables W72, W73, W85, W93, W146, and W147 are easily damaged. DO NOTbend them. Bending the cables can damage the center conductor, which couldresult in power “holes”.
