Symmetricom 5071A, Assembly And Service Manual

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4. Replacing Assemblies - Disassembly and Reassembly
To Remove A17 CBT Assembly
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4 Look for the black coax cable that comes from the left side of the CBT
and enters under a perforated RF cover. This is held in place with a tie
wrap in a bundle with other wires. If the tie wrap is easy to access,
proceed to step 5. If not, it may be necessary to remove the inner-top
shield. This requires using a TORX® T10 driver to remove the 31 screws
holding the cover in place.
5 With the bottom exposed, disconnect the right-angle SMB connector from
the A14 Signal Amplifier module. This connector is part of a black coax
cable connected to the Cesium Beam Tube.
Perform the remaining steps from the top of the instrument.
6 Clip the tie wrap holding the black signal coax cable in a bundle with other
cables.
7 Use the 5/16” open-end wrench to carefully loosen SMA nut holding the
rigid coax to the Microwave Adapter. Continue to loosen the SMA nut with
your fingers until it is completely disconnected. The Microwave Adapter is
a small metal device that is part of the CBT, towards the rear, near the
tube center.
8 Record the position of the two High Voltage cables for later reassembly.
9 Unscrew the two High Voltage connectors using only your fingers.
Do not use any pliers or wrenches, as these can crack the plastic or
ceramic.
10 Remove the two multiple pin connectors from the A2 CBT Controller
assembly. These are held in place with sliding locks.
11 Use the TORX® T25 driver to remove the four screws holding brackets
and CBT in place.
12 Being careful not to bend the rigid coax, lift the CBT directly up from the
cavity. The black signal coax should come free without interference, but
pay attention to it to be sure it is not damaged.
CBT Installation
NOTE Follow the installation instructions carefully. They are NOT
simply the reverse order of the previous process.
13 While guiding the black signal coax into its proper place, lower the
replacement CBT into the cavity in the same position as the one
removed.