Attenuators - Keysight N5221A Service Manual

Repair and Replacement Procedures
Removing and Replacing the A34–A37 Source Attenuators, the A38–A41 Bias Tees, and the A42–A45 Receiver

Attenuators

Removing and Replacing the A34–A37 Source Attenuators, the A38–A41 Bias
Tees, and the A42–A45 Receiver Attenuators
Tools Required
• T-10 TORX driver (torque to 9 in-lb or 1.02 N.m)
• T-20 TORX driver (torque to 21 in-lb or 2.38 N.m)
• 5/16-inch open-end torque wrench (torque to 10 in-lb or 1.13 N.m)
• ESD grounding wrist strap
Removal Procedure
Refer to Figure 7-20 for this procedure.
CAUTION Be careful not to damage the center pins of the semirigid cables. Some flexing of the cables
is necessary to remove assemblies but do not over-bend them.
1. Disconnect the power cord.
2. Remove the outer cover. Refer to
3. Remove the front panel assembly. Refer to
page 7-8.
4. Position the analyzer bottom side up.
5. The source and receiver attenuator pair, the associated bias tee, and the bracket to which they are
attached, must be removed as a complete assembly. For some models, especially 2-port models, this
may not be necessary; it may be possible to remove only the bias tee. In this case, refer to
and Replacing the A38–A41 Bias Tees" on page
6. Disconnect the ribbon cable (item
7. Disconnect the wire harness cable (item
motherboard.
8. Disconnect two semirigid cables (item
removed. It may be necessary to remove additional cables to remove the attenuator bracket. If so, note the
location and orientation of each for reinstallation later.
9. Remove three screws (item
10. Move the disconnected semirigid cables out of the way and lift the attenuator bracket out of the
analyzer, with the attenuators and bias tee attached.
11. Remove two screws (item
bracket.
Replacement Procedure
1. Reverse the order of the removal procedure.
Torque all cable connections to 10 in-lbs.
2. Perform the post-repair adjustments, verifications, and performance tests that pertain to this removal
procedure. Refer to Table 7-2 on page
7-42
"Removing the Covers" on page
"Removing and Replacing the Front Panel Assembly" on
7-44.
①
) from the attenuators to be removed.
➁
), for the bias tee to be removed, from the A19 test set
③
) from each step attenuator and from each bias tee to be
④
) that secure the attenuator bracket to the test set deck.
⑤
) to remove the attenuator or bias tee to be replaced, from the mounting
7-56.
PNA Series Microwave Network Analyzers
7-6.
Service Guide N5222-90001
N5221A/22A
"Removing