Keysight N5224B, Service Manual

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7-44 Keysight N5224B/25B Service Guide
Repair and Replacement Procedures
Removing and Replacing the A27 and A28 Mixer Bricks
7-
Note the locations of each of the gray flexible cables for reconnection
later. If necessary, refer to the appropriate bottom cable illustration in
Chapter 6 .
Disconnect these cables and remove the mixer brick mounting block, with
the mixer brick(s), the mixer brick shields, and the A26 splitter attached,
from the analyzer.
8. If replacing a mixer brick:
a. Remove the two screws (item

) from each shield.
b. Remove 3 screws (not shown) that fasten each mixer brick to the
mixer brick mounting block.
Replacement Procedure
1. Reverse the order of the removal procedure.
If replacing the A28 mixer brick, remember to move the dust
cap/termination (item

) from the old mixer brick to the new mixer brick
in the same location.
Some 2-port models and some 4-port models have a 3-dB pad on the A27
mixer brick R1 connection and all 4-port models have a 3-dB pad on the
A28 mixer brick R4 connection. If appropriate, be sure to move the pad(s)
from the old mixer brick(s) to the new mixer brick(s).
Torque all RF 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 7-78 .