Aircraft

1. General
A. This maintenance practice provides removal/installation and adjustment/test procedures for the HF antenna coupler(s). The HF antenna coupler(s) are located in the aft accessory compartment at the tail cone attaching frame. Access to the HF antenna coupler(s) is through the access door in the lower surface of the tail cone, or through the emergency exit in the aft pressure bulkhead.2. Equipment and Materials
NOTE: Equivalent substitutes may be used in place of the following item; which is used to perform test of antenna coupler.
NOTE: Some materials in the Equipment and Materials list may not be permitted to be used in your location. Persons in each location must make sure they are permitted to use these materials. All persons must obey all applicable federal, state,local, and provincial regulations for their location.

3. Removal/Installation HF Antenna Coupler
A. Remove HF Antenna Coupler
WARNING: TAG AND USE SAFETY CLIPS TO SAFETY THE CIRCUIT BREAKERS. IF THE CIRCUIT BREAKERS ARE NOT OPENED, TAGGED, AND SAFETIED, INJURY TO PERSONS AND DAMAGE TO EQUIPMENT CAN OCCUR.
(1) Open these circuit breakers and install safety tags:
LOWER EPC, XFER BUS
Row ColNumber Name
T 42 B10-386 FLIGHT INTERPHONE -2
OVERHEAD EMERGENCY DC BUS
Row Col Number Name
XR 117, 120-124, 153, 160, 179, 181, 182, 184, 191-196
A 10 B10-47 FLIGHT INTERPHONE-1
XR 183, 185
A 11 B10-47 FLIGHT INTERPHONE-1
UPPER EPC, LEFT RADIO AC BUS
Row Col Number Name
XR 117, 120-124, 130-133, 137, 140, 160, 179, 181-183, 185, 191-196, 616, 618, 619,
623
D 15 B10-195 HF COMM-1 PHASE AD 16 B10-196 HF COMM-1 PHASE B
Row Col Number Name
D 17 B10-197 HF COMM-1 PHASE C
UPPER EPC, LEFT RADIO DC BUS
Row Col Number Name
E 15 B10-198 HF COMM-1
UPPER EPC, RIGHT RADIO AC BUS
Row Col Number Name
XR 117, 120-124, 130-133, 137, 140, 160, 181-183, 185, 191-196, 616, 618, 619, 623
D 3 B10-201 HF COMM-2 PHASE A
D 4 B10-202 HF COMM-2 PHASE B
D 5 B10-203 HF COMM-2 PHASE C
UPPER EPC,RIGHT RADIO DC BUS
Row Col Number Name
E 3 B10-204 HF COMM-2
XR 117, 120-124, 130-133, 137, 140, 153, 160, 179, 181-185, 191-196, 616, 618, 619,
623
(2) At antenna coupler disconnect coaxial cable, electrical power, and air connectors from unit.
(3) Remove outboard screws from support which attaches HF antenna coupler to structure.
(4) While holding HF antenna coupler, loosen clamp whichattaches HF antenna coupler to lightning arrestor and relay unit.
(5) Move HF antenna coupler away from forward face of lightning arrestor and relay unit, and remove HF antenna coupler.
B. Install HF Antenna Coupler
WARNING: TAG AND USE SAFETY CLIPS TO SAFETY THE CIRCUIT BREAKERS. IF THE CIRCUIT BREAKERS ARE NOT OPENED, TAGGED, AND SAFETIED, INJURY TO PERSONS AND DAMAGE TO EQUIPMENT CAN OCCUR.(1) Make sure that these circuit breakers are open and have safety tags:
LOWER EPC, XFER BUS
Row Col Number Name
T 42 B10-386 FLIGHT INTERPHONE -2
OVERHEAD EMERGENCY DC BUS
Row Col Number Name
XR 117, 120-124, 153, 160, 179, 181, 182, 184, 191-196
A 10 B10-47 FLIGHT INTERPHONE-1
XR 183, 185
A 11 B10-47 FLIGHT INTERPHONE-1
UPPER EPC, LEFT RADIO AC BUS
Row Col Number Name
XR 117,120-124, 130-133, 137, 140, 160, 179, 181-183, 185, 191-196, 616, 618, 619,
623
D 15 B10-195 HF COMM-1 PHASE A
D 16 B10-196 HF COMM-1 PHASE B
D 17 B10-197 HF COMM-1 PHASE C
UPPER EPC, LEFT RADIO DC BUS
Row Col Number Name
E 15 B10-198 HF COMM-1
UPPER EPC, RIGHT RADIO AC BUS
Row Col Number Name
XR 117, 120-124, 130-133, 137, 140, 160, 181-183, 185, 191-196, 616, 618, 619, 623
D 3 B10-201 HFCOMM-2 PHASE A
D 4 B10-202 HF COMM-2 PHASE B
D 5 B10-203 HF COMM-2 PHASE C
UPPER EPC, RIGHT RADIO DC BUS
Row Col Number Name
E 3 B10-204 HF COMM-2
XR 117, 120-124, 130-133, 137, 140, 153, 160, 179, 181-185, 191-196, 616, 618, 619,
623
(2) Make certain that mating contacts of HF antenna coupler and lightning arrestor and relay unit are clean.
(3) Place loosened clamp around mounting flange...