Symmetricom 5071A, Assembly And Service Manual

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4. Replacing Assemblies - Disassembly and Reassembly
To Remove A12 Dc-Dc Power Converter Module
164
To Remove A12 Dc-Dc Power
Converter Module
1 Ensure that the top, bottom, and left-side covers are removed.
2 Remove 3 screws from the plate that holds A16 in place, attached
at the top of A12 (1 screw) and the Toroid power transformer T1
(2 screws).
3 Remove 11 flat-head screws from the left-rear chassis frame
located within the perimeter of A12.
4 Remove 4 screws holding a small (11/16” x 1 3/16”) plate (used
for rack mounting).
5 Loosen (do not remove) 2 screws that hold the line filter/cable
assembly to the rear panel to gain clearance for A12 removal.
6 Clip the A12 cable assembly wire tie.
7 Disconnect A12 power cable from A1.
8 Push A12 forward from the rear and up from the bottom,
alternately back and forth until the unit is free.
9 Lift A12 out from the chassis and set aside and install a
new/functional unit.
10 If A16 requires replacement at this time, disconnect its cable
assembly-to-instrument connections and remove it from the
instrument.
(Be sure to tag the high-voltage lines attached to the CBT before
unscrewing these connectors, using only your fingers to avoid
damage.)
11 Install new/functional A16 as required by reversing the above
procedural steps.