Keysight N5227A - Removing and Replacing the A27 and A28 Mixer Bricks

7-30 Service Guide N5227-90001
Repair and Replacement Procedures PNA Series Microwave Network Analyzers
Removing and Replacing the A27 and A28 Mixer Bricks N5227A
Removing and Replacing the A27 and A28 Mixer Bricks
Tools Required
• T-8 TORX driver (set to 6 in-lb or 0.68N.m)
• T-10 TORX driver (set to 9 in-lb or 1.02 N.m)
• T-20 TORX driver (set to 21 in-lb or 2.38 N.m)
• 5/16 inch open-end torque wrench (set to 1.13 in-lb)
• ESD grounding wrist strap
Removal Procedure
Refer to Figure 7-9 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 the assembly. However, do not over-bend the semirigid cables.
1. Disconnect the power cord.
2. Remove the outer cover. Refer to “Removing the Covers” on page 7-6.
3. Position the analyzer bottom side up.
4. Remove the A26 splitter. Refer to “Removing and Replacing the A26 Splitter” on page 7-28.
5. The mixer bricks and the mounting blocks to which they are attached, must be removed as a complete
assembly. 
Disconnect all semirigid cables (item
①
) from the mixer bricks on the mounting blocks to be removed.
6. Disconnect the ribbon cables (item
➁) from each of the mixer bricks.
7. Remove ten screws (item
③
) from the mixer brick mounting block.
8. Move the disconnected semirigid cables out of the way and lift the mixer brick mounting block out of the
analyzer just enough to allow the gray flexible RF cables (item
④
) to be disconnected. It may be
necessary to loosen the connector at the other end of some of the semirigid cables to allow them to be
moved enough.
Note the locations of each of the gray flexible cables for reconnection later. Disconnect these cables
and remove the mixer brick mounting block with the mixer brick(s) from the analyzer.
9. If replacing a mixer brick, remove 3 screws (not shown) that fasten each mixer brick to the mixer brick
mounting block.
10. If replacing the A28 mixer brick, remove the 3 dB pads (item
⑤
) and keep it for reinstallation on the
replacement mixer brick.