HP 8560A, Service Manual

Page: 111 / 450

Procedure 2. Al Front Frame/A18 CRT
Removal
Warning
The voltage potential at is Disconnect at the CRT with caution!
Failure to properly discharge may result in
severe electrical
to
personnel and damage to the instrument.
1. Remove the analyzer’s cover assembly as described in Procedure 1, “Analyzer Cover.”
2. Fold out the A2, A3, A4, and A5 assemblies as described in Procedure 5, A3, A4,
and A5 Assemblies Removal,” steps 2 through 6.
3. Disconnect from
4. Place the analyzer top-side-up on the work bench.
5. Connect the analyzer’s line-power cord to provide proper grounding while discharging the
post-accelerator cable. Make sure that the analyzer’s line-power switch is in the
off position.
6. Connect a high-voltage probe
such as the HP 34111A to a voltmeter with a
10 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 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 (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 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 from the CRT
shield assembly.
13. Carefully unsnap the post-accelerator cable from the CRT and discharge it by
shorting the cable to chassis ground on the CRT shield assembly.
14. Place the analyzer on its right side frame with the front-frame assembly hanging over the
front edge of the work bench.
15. Fold out the Al4 and Al5 assemblies as described in Procedure 9, “Al4 and Al5
Assemblies Removal,” steps 3 and 4.
3-4 Assembly Replacement