JUL 2020 Chapter 90 Police Version Page 90.15
90-160 F079-1 PA/Siren System Installation
A. Speaker Removal
1. Refer to Figure 90-1. Turn battery switch off & pull-out associated circuit breaker.
2. Cut safety wire securing speaker cone to F644-1 bracket.
3. Unscrew cone and remove cone and speaker horn. Cut and discard remaining
safety wire from inside of cone.
4. Slide back nipples and wire receptacles off of speaker electrical turrets.
5. Cut and discard speaker mounting bolt safety wire and remove bolts. Supporting
speaker, remove two remaining mounting screws and hardware, and remove
speaker.
B. Speaker Installation
1. Refer to Figure 90-1. Turn battery switch off & pull-out associated circuit breaker.
2. Remove cone and speaker horn from speaker. Position speaker with drain hole
down in F644-1 bracket and install mounting hardware. Special torque two bolts
to 60 in.-lb., install 0.032-inch diameter lockwire, and safety bolts together. Verify
speaker security.
3. Slide wire receptacles on speaker electrical turrets. Slide nipples over connections.
4. Install 0.032-inch diameter lockwire inside of cone and prepare safety. Position
speaker horn, drilled hole on top, on speaker and install and tighten cone. Thread
safety through hole and safety cone to bracket. Verify security.
CAUTION
Hearing loss can result if personnel do not wear appropriate
hearing protection when in close proximity to an operating PA/
Siren.
5. Push-in associated circuit breaker & turn battery switch on. Wearing appropriate
hearing protection, perform appropriate post-installation function checks. Turn
battery switch off.
C. Amplifier Removal
1. Refer to Figure 90-1. Turn battery switch off & pull-out associated circuit breaker.
2. Open baggage compartment door. Remove aft left back rest per § 25-22.
3. Disconnect airframe wiring from amplifier at connectors. Remove hardware
securing amplifier to G259-1 bulkhead and remove amplifier.
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