Keysight Technologies N5247B, Service Manual

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7-80 Keysight N5247B Service Guide
Repair and Replacement Procedures
Removing and Replacing the A71–A74 Bias Tee Combiners
7-
7. Make note of the orientation of the two cable wires and ground cable
clamp for reinstallation later.
— Remove the DC bias cable (item

) from the Bias Combiner. Refer
to Figure 7-42 on page 7-81 . See also Figure 7-44 on page 7-82 .
— Remove the screw, cable ground clamp, and RF cable (item

) from
the Bias Combiner. Refer to Figure 7-42 on page 7-81 . See also
Figure 7-45 on page 7-82 .
8. Remove two screws that attach the bias tee combiner to the bracket (Now
do item

). Refer to Figure 7-43 on page 7-81 .
9. Repeat steps
4
through
7
for the other bias combiners.
Replacement Procedure
1. Reverse the order of the removal procedure.
— Torque the bias combiner screws (x2) to the chassis to 9 in-lbs.
— Mark the bias combiner connectors with a fine permanent marker.
Refer to Figure 7-46 on page 7-83 .
— Remember to place the cable ground clamp on the bias tee
combiner’s RF IN connector.
— Torque the cable ground clamp to bias combiner to 6 in-lbs.
— Torque the bias combiner with bracket assembly (to the chassis)
screws (x2) to 9 in-lbs.
2. As shown in Figure 7-43 on page 7-81 , position the bias tees on the
attenuator brackets as indicated.
3. Perform the post-repair adjustments, verifications, and performance tests
that pertain to this removal procedure. Refer to Table 7-2 on page 7-92 .
Ensure that when the bias combiner semirigid cables are torqued that one
5/16 in wrench is used to stabilize the connector on the combiner and the
second wrench is used to torque the semirigid cable to 10 in-lbs.
IMPORTANT! Some figures show examples of more than one bias combiner
or bias combiner cable being remove. is It only necessary to remove the
defective bias combiner.