Honeywell Chadwick-Helmuth 8500C Maintenance Manual page 146

Appendix A - 8520C-36 Signal Selector
A.4.8.2 Dual Filter Assy. and Cable Harnesses
a. Install filter (2) in chassis (11) and secure with four 4-40 X 3/8 php. blk. screws (3) and
four #4 intl. lock .260" washers (7).
b. Install external connectors and harness (19, 20) in chassis (11) and secure with eight 4-40
X 3/8 php. blk. screws (3).
A.4.8.3 Connector Boards A1
NOTE: Do not reuse old screws to install nut rings.
a. Install eight nut rings (26, 27) and four connector boards A1.
NOTE: Make sure ground wire is attached to connector lug as shown in Figure A-11.
A.4.8.4 Mux Board A4
a. Make sure Mux board A4 has six #4 shoulder washers wedged into its holes and connect
four connectors (J1, J2, J3, J4) to Mux board.
b. Align Mux board with hexagonal posts in chassis.
c. Place six #4 .25" o.d. spacers (9) and six flat nylon washers (30) on top of Mux board
holes (temporarily hold in place with spare wires or the like).
A.4.8.5 Controller Board A3
a. Place controller board A3 on top of Mux board spacers and secure at 5 places with five 4-
40 X 3/4 php. blk. screws (5) and five flat nylon washers (30). Secure the sixth hole with
one 4-40 X 7/8 php. blk. screw (29), one washer (30), and one cable clamp (31).
b. Connect four connectors (J1, J2, J3, P2) on controller board A3.
c. Install bottom cover (12) and secure with eighteen 4-40 X 3/8 pan php. blk. screws (3) and
eighteen #4 intl. lock .260" washers (7).
A-24 Chadwick-Helmuth A Business Unit of Honeywell International, Inc.