Procedure 13. Rear Frame/Rear Dress Panel

Removal

Warning The A8 Power Supply and A6Al High Voltage assemblies contain lethal voltages with lethal currents in all areas. Use extreme care when servicing these assemblies. Always disconnect the power cord from the instrument before beginning this replacement procedure. Failure to follow this precaution can represent a shock hazard which may result in personal injury.

1.Disconnect the line-power cord from the analyzer.

2.Remove the analyzer’s cover, and place the analyzer on its right side frame.

3.Fold out the A2, A3, A4, and A5 assemblies as described in Procedure 5, “A2, A3, A4, and A5 Assemblies Removal,” steps 3 through 5.

4.Disconnect the HP-IB cable at A2J5.

5.Place the analyzer top-side-up on the work bench with A2 through A5 folded out to the right.

Warning The voltage potential at A6AlW3 is +9 kV. Disconnect at the CRT with caution! Failure to properly discharge A6AlW3 may result in severe electrical shock to personnel and damage to the instrument.

6.Connect the analyzer’s line-power cord to provide proper grounding while discharging the A6AlW3 post-accelerator cable. Make sure that the analyzer’s line-power switch is in the off position.

7.Connect a high-voltage probe (lOOO:l), such as the HP 34111A to a voltmeter with a 10 megohm input.

8.Connect the clip lead of the probe (ground) to the chassis of the spectrum analyzer.

9.Slip the tip of the high-voltage probe under the A6AlW3 post-accelarator cable’s rubber shround to obtain a reading on the voltmeter. See Figure 3-2.

10.Keep the high-voltage probe on the post-accelerator connector until the voltage has dropped to a voltmeter reading of less than 5 mV (1ess than 5 V at the connector). This normally takes about 30 seconds.

11.Disconnect the line-power cord from the spectrum analyzer.

12.Using a small screwdriver with the shank in contact with the CRT shield assembly, slip the tip of the screwdriver under the A6AlW3 post-accelerator cable’s rubber shroud and short the cable to ground on the CRT shield assembly. See Figure 3-2.

13.Remove the three screws securing the power-supply shield to the power supply, and remove the shield.

14.Disconnect the fan and line-power cables from A6J3 and A6JlOl on the A6 Power Supply assembly.

3-40 Assembly Replacement