Procedure 13. Rear Frame/Rear Dress Panel
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
present a shock hazard which may result in personal injury.
1. Disconnect the line-power cord from the spectrum analyzer.
2. Remove the spectrum analyzer cover, and place the spectrum 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 spectrum 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 spectrum analyzer line-power cord to provide proper grounding while
discharging the
A6AlW3
post-accelerator cable. Make sure that the spectrum analyzer
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 rubber shroud of the
A6AlW3
post-accelerator cable to obtain a reading on the voltmeter. See Figure 4-2.
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
(1
ess 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 rubber shroud of the
A6AlW3
post-accelerator cable
and short the cable to ground on the CRT shield assembly. See Figure 4-2.
13. Remove the three screws (1) securing the power-supply shield to the power supply, and
remove the shield. See Figure 4-23.
14. Disconnect the fan and line-power cables from A6J3 and
A6JlOl
on the A6 power supply
assembly.
4-44 Assembly Replacement