316 Chapter7
Replacing Major Assemblies
A3 Front-End Assembly
Replacement
1. Tuck all cables and wire harnesses on the A3 Front-End assembly
(except for cables W20 and W24) down into the space (5) between
the “D” bracket and the A3A9 filter. This reduces the possibility of
damaging wires while replacing the front-end assembly. See
Figure 7-8.
2. Place the instrument on the work surface with the top side facing up.
3. Set the front-end assembly on top of the A2 Display assembly and
route the W20 coaxial cable into the slot on the instrument chassis
that is just below the lower-right rear corner of the A2 Display
assembly.
4. Position the front-end assembly over the front-end section of the
instrument chassis.
CAUTION Protect the center pin of the W10 semi-rigid cable and make sure that
cables W20 and W24, as well as all other wiring, are not pinched
between the front-end assembly and the instrument.
5. Carefully lower the front-end assembly into the instrument chassis.
6. Replace the front-end-to-IF support bracket, and install the three
screws and two washers (4) on the bracket without tightening.
7. Connect W8 (1) to A9J5 and W9 (2) to A9J4. See Figure 7-8.
8. If the instrument came equipped with an LO Output on the rear
panel (Option 009), connect W42 (3) to the LO OUTPUT connector
on the rear-frame assembly.
9. Place the instrument so that its left side is resting on the work
surface.
10.Install and tighten the four screws (3) that secure the front-end
assembly to the chassis. See Figure 7-7.
11.Route W20 through the slot (2) in the instrument chassis and under
the ribbon cable.
12.Connect W20 (1) to the AT1 assembly and tighten it to
10 inch-pounds.
13.Place the instrument on the work surface with the top side facing
up.
14.Tighten the three screws (4) on the front-end-to-IF support bracket.
See Figure 7-8.
15.Replace the A7 Analog Board assembly. Refer to the “A7 Analog
Interface Assembly.” replacement procedure.
To Next Page
Loading...
Need help?
General
