HP 8560A

Procedure 7. A6Al High Voltage Assembly
Removal
Warning
The A6 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 power cord from the analyzer.
2. Remove the analyzer’s cover assembly as described in Procedure 1.
3. Fold out the A2, A3, A4, and A5 assemblies as described in Procedure 5, “A2, A3, A4,
and A5 Assemblies.”
4. Place the analyzer top-side-up on the work bench.
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.
5. 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.
6. Connect a high-voltage probe (lOOO:l), such as the HP 34111A to a voltmeter with a
10 megohm input.
7. Connect the clip lead of the probe (ground) to the chassis of the spectrum analyzer.
8. 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.
9. Keep the high-voltage probe on the post-accelerator connector until the voltage has
dropped to a voltmeter reading of less than 5 mV (less than 5 V at the connector). This
normally takes about 30 seconds.
10. Disconnect the line-power cord from the spectrum analyzer.
11. 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.
12. Pry out the black grommet protecting post-accelerator cable A6AlW3 from the CRT
shield assembly.
13. Carefully unsnap the A6AlW3 post-accelerator cable from the CRT and discharge it by
shorting the cable to chassis ground on the CRT shield assembly.
14. Remove the three screws securing the power supply shield to the power supply and remove
the shield.
15. Remove the three screws and washers securing the A6Al High Voltage assembly to the A6
Power Supply assembly.
3-22 Assembly Replacement