Overview
The junction box is an electrical interface for the aircraft's electrical systems. There are four junction boxes on each aircraft. They operate as a component of the wire harness and contain components necessary to operate the aircraft. The junction boxes are used to connect signals together, do mechanical connection functions and do system tests in the aircraft. The junction box supplies no signals, and does not decrease or stop signals(unless the relays are used to set a system from one to the other).
09/29/21
Junction Boxes
Each junction box has an ARINC 600 receptacle size 3 connector at the rear of the unit. This connector connects to a receptacle on the mounting tray when the junction box is installed. The mounting tray has two hold down clamps that lock the junction box into the tray.
Each junction box contains five front printed circuit-cards that can be removed. The front cover of the junction box can be removed to give access to the circuit-cards and it is not necessary to disconnect the hold down clamps.
The personnel can remove and replace the circuit-card easily by hand from the front of the junction box. All printed circuit-cards are specially made to be correctly installed to prevent an installation in the incorrect location.
The circuit-cards are isolated for electrical continuity and maintenance purpose. For example, the circuit-cards do not contain more than two critical electrical systems. Also, the circuit-cards contain electronic components necessary to move the heat away from the junction box.
Junction Box JB1
Junction box JB1 is installed in a mounting tray in the LH equipment rack. The JB1 contains five circuit-cards. Each circuit-card is identified on its front side. The related circuit-card number is shown on the front face of the case.
Junction Box 1, Board 1
| System | Test Points | Miscellaneous Equipment |
|---|---|---|
| Anti Ice System Low Temp | JB1-D Pin 6B, 6D, 6F Test Point 19 | N/A |
| Anti Ice Wing Cross Bleed | JB1-D Pin 6G, 6J, 7B Test Point 25 JB1-D Pin 7A, 6H, 6K Test Point 22 |
N/A |
| Engine ID and Secondary System Selection Left | JB1-D Pin 12D, 12F, 12H, 12K, 13B, 13D Test Point 97 ARINC Hi JB1-D Pin 12G, 12E, 12J, 13A, 13C, 13E Test Point 100 ARINC Lo |
LA-FADEC-1 Bus |
| Engine ID and Secondary Systems Selection Left | JB1-E Pin 26, 27, 21, 28, 29 Test Point 13 | N/A |
| EFIS Checklist Control | JB1-E Pin 30, 31, 32 Test Point 10 | N/A |
| Spare | JB1-E Pin 54 (Relay X1) Test Point 21 JB1-E Pin 55 (Relay X2) Test Point 5 JB1-D Pin 7D (Relay A1) Test Point 11 JB1-D Pin 7C (Relay A2) Test Point 24 JB1-D Pin 7E (Relay A3) Test Point 28 JB1-D Pin 7G (Relay B1) Test Point 14 JB1-D Pin 7F (Relay B2) Test Point 8 JB1-D Pin 7H (Relay B3) Test Point 18 |
Relay K172 |
| Field Loadable Software | JB1-E Pin 56 (Relay X1) Test Point 49 JB1-E Pin 57 (Relay X2) Test Point 31 JB1-D Pin 7K (Relay A1) Test Point 55 JB1-D Pin 7J (Relay A2) Test Point 52 JB1-D Pin 8A (Relay A3) Test Point 46 JB1-D Pin 8C (Relay B1) Test Point 34 JB1-D Pin 8B (Relay B2) Test Point 40 JB1-D Pin 8D (Relay B3) Test Point 37 JB1-D Pin 8F (Relay C1) Test Point 33 JB1-D Pin 8E (Relay C2) Test Point 43 JB1-D Pin 8G (Relay C3) Test Point 23 JB1-D Pin 8J (Relay D1) Test Point 27 JB1-D Pin 8H (Relay D2) Test Point 30 JB1-D Pin 8K (Relay D3) Test Point 17 |
Relay K159 |
| IASC Bus Interface | JB1-D Pin 11B, 11D, 11F Test Point 91 ARINC Hi JB1-D Pin 11C, 11E, 11GTest Point 94 ARINC Lo |
IASC2-A Bus |
| Audio Integration System Interconnect | JB1-D Pin 11H, 11K, 12B, 13F Test Point 92 ARINC Hi JB1-D Pin 11J, 12A, 12C, 13G Test Point 95 ARINC Lo |
LB-RIU-14 Bus |
| Integrated Avionics Processor (L-GP-5) Bus | JB1-D Pin 15E, 15B, 15H Test Point 81 ARINC Hi JB1-D Pin 15J, 15C, 15F Test Point 78 ARINC Lo |
L-GP-5 Bus |
Junction Box 1, Board 2
| System | Test Points: Discrete Black, ARINC Blue | Miscellaneous Equipment |
|---|---|---|
| Traffic Collision Avoidance System Power & Control | JB1-A Pin 11A, 11C, 11E, 11G, 11B, 11D, 11F, 11H Test Point 4 JB1-A Pin 11J, 12A, 11K, 12B Test Point 99 JB1-A Pin 12J, 12K, 13A Test Point 101 JB1-A Pin 14A, 14B, 14C Test Point 95 JB1-D Pin 4D, 4H, 4F Test Point 85 ARINC Hi JB1-D Pin 4E, 4J, 4G Test Point 88 ARINC Lo |
TTR-TA/RA-2 Bus |
| Air Conditioning System Hot Air Shut-off Valves | JB1-A Pin 12C, 12E, 12D Test Point 102 | N/A |
| Cockpit Miscellaneous Reading / Stowage Lights | JB1-A Pin 14G, 14H, 14J, 15H, 13J Test Point 92 | N/A |
| Emergency Locator Transmitter | JB1-A Pin 14K, 15A Test Point 100 | 7.5K Resistor (R8) |
| Rudder Pedal Adjust Electrical System | JB1-A Pin 15B, 15D, 15C Test Point 97 JB1-A Pin 15E, 15F, 15G, Test Point 94 |
N/A |
| Cockpit Integral Lighting Power & Control | JB1-E Pin 23, 24, 25 (Relay X1) Test Point 37 JB1-E Pin 21 (Relay X2) Test Point 40 JB1-A Pin 13E, 13G (Relay A1) Test Point 46 (through R33) JB1-A Pin 13F (Relay A2) Test Point 43 JB1-A Pin 13H (Relay A3) Test Point 98 (through R21, R23) Test Point 96 (through R21 or R25, or R29 only) Test Point 29 (Direct from relay A3) JB1-A Pin 14F (Relay B1) Test Point 62 JB1-A Pin 14E (Relay B2) Test Point 65 JB1-A Pin 13H (Relay B3) Test Point 98 (through R37) JB1-D Pin 2F, 2G, Test Point 70 |
K179, Several resistors |
| Air Data Computer O/P 1 | JB1-D Pin 2B, 3D, 3C Test Point 80 ARINC Hi JB1-D Pin 2C, 3E, 3B Test Point 83 ARINC Lo |
L-ADC-1 Bus |
| Hydraulic Power Control, Left SOV | JB1-E Pin 10 (Relay X1) Test Point 10 JB1-E Pin 9, 11 (Relay X2) Test Point 13 JB1-E Pin 15, 16 (Relay A1) Test Point 1 JB1-E Pin 10 (Relay A2) Test Point 10 JB1-E Pin 14 (Relay A3) Test Point 2 |
Relay K59 |
| Air Conditioning System L Bleed & High Pressure Valves | JB1-E Pin 17 (Relay X1) Test Point 28 JB1-E Pin 19 (Relay X2) Test Point 31 JB1-E Pin 17 (Relay B2) Test Point 28 JB1-E Pin 18, 20 (Relay B3) Test Point 34 |
Relay K11 |
| Lighting Interface | JB1-A Pin 14D, 15J, 15K, JB1-D 1A Test Point 91 | N/A |
| Oxygen System Electrical | JB1-D Pin 1H, 1K, 2H Test Point 78 | N/A |
| ADC Data Load Switching | JB1-D Pin 2K, 3F, 3K Test Point 87 ARINC Hi JB1-D Pin 3A, 3G, 4A Test Point 90 ARINC Lo |
L-SIM-1 Bus |
| Hydraulic Motor Driven Generator | JB1-E Pin 7 (Relay X1) Test Point 49 JB1-E Pin 22 (Relay X2) Test Point 17 JB1-A Pin 12G (Relay A1) Test Point 8 JB1-E Pin 7 (Relay A2) Test Point 5 JB1-A Pin 13C (Relay B1) Test Point 11 JB1-A Pin 13B (Relay B2) Test Point 14 |
Relay K169 |
Junction Box 1, Board 3
| System | Test Points: Discrete Black, ARINC Blue | Miscellaneous Equipment |
|---|---|---|
| Air Conditioning System Engine Off | JB1-A Pin 1A, 1E, 1C Test Point 94 JB1-A Pin 1B, 1F, 1D Test Point 101 |
N/A |
| Aileron System Position Sensors and Roll Disconnect | JB1-A Pin 2C, 2E, 2F, 2D Test Point 100 | N/A |
| ATC 1 Transponder | JB1-A Pin 3F, 3H, 3K, 4B, 4D, 4F, 4H, 4K, 5B, 5D, 5F, 5H, 5K, 3G, 3J, 4A, 4C, 4E, 4G, 4J, 5A, 5C, 5E, 5G, 5J Test Point 1 | N/A |
| Electronic Flight Information System Displays Reversion | JB1-A Pin 2G, 2H, 2K, 2J Test Point 5 JB1-A Pin 3A, 3B, 3C Test Point 2 |
N/A |
| Integrated Avionics Processing System (L-GP-5) | JB1-A Pin 6H, 6K, 7B, 7D, 7F, 7H, 7K Test Point 61 ARINC Hi JB1-A Pin 6J, 7A, 7C, 7E, 7G, 7J, 8A Test Point 64 ARINC Lo |
L-GP-5 Bus |
| Radio Altimeter | JB1-A Pin 8B, 8F, 8D Test Point 67 ARINC Hi JB1-A Pin 8C, 8G, 8E Test Point 70 ARINC Lo |
LS-RALT-1 Bus |
| AHRS Interface | L-AHC-1 JB1-A Pin 8H, 10E, 10B Test Point 73 ARINC Hi JB1-A Pin 8J, 10F, 10C Test Point 76 ARINC Lo R-AHC-3 JB1-A Pin 8K, 9H, 9D Test Point 62 ARINC Hi JB1-A Pin 9A, 9J, 9E Test Point 65 ARINC Lo L-AHC-2 JB1-A Pin 9B, 9K, 9F Test Point 68 ARINC Hi JB1-A Pin 9C, 10A, 9G Test Point 71 ARINC Lo |
L-AHC-1, R-AHC-3, L-AHC-2 Bus |
| Oxygen System Electrical | JB1-B Pin 31, 33, 32, Test Point 4 JB1-B Pin 44, 47, 51 Test Point 13 |
N/A |
| EICAS Power & Indication | JB1-B Pin 34, 35, 36 Test Point 8 | N/A |
| Brake Control System & PSEU Interface | JB1-B Pin 37, 39, 40 Test Point 9 JB1-B Pin 38, 41 Test Point 7 |
N/A |
| General Radio Tuning Emergency Frequency Selection | JB1-B Pin 42, 45, 48, 50 Test Point 10 JB1-B Pin 43, 46, 49, 52 Test Point 12 JB1-A Pin 1H, 1K, 2A, 1J Test Point 91 |
N/A |
| Air Data Computer Data Load Switching | JB1-A Pin 5B, 6D, 5F Test Point 74 ARINC Hi JB1-A Pin 6C, 5E, 6G Test Point 77 ARINC Lo |
N/A |
Junction Box 1, Board 4
| System | Test Points: Discrete Black, ARINC Blue | Miscellaneous Equipment |
|---|---|---|
| Lightning Detection Optional System Interface | JB1-F Pin 2A, 2F Test Point 77 JB1-F Pin 2A Test Point 34 (CR12) JB1-F Pin 2A Test Point 37 (CR10) JB1-F Pin 2A, 2C, 7D Test Point 40 (CR9) JB1-F Pin 7E, 7F, Test Point 40 (CR37) |
Four Diodes, CR9, 10, 12, & 37 |
| Lightning Detection Optional System Power & Control | JB1-F Pin 9D, 9F, 9H, 9k, 10B Test Point 49 ARINC Hi JB1-F Pin 9E, 9G, 9J, 10A, 10C Test Point 52 ARINC Lo |
LDS-1 Bus |
| General Radio Tuning Display Right System | RB-RIU-9 JB1-F Pin 9B, 8H, 8K, 6B Test Point 55 ARINC Hi JB1-F Pin 9A, 9C, 8J, 6C Test Point 58 ARINC Lo L-RIU-11 JB1-F Pin 5H, 5D, 5F Test Point 50 ARINC Hi JB1-F Pin 5J, 5E, 5G Test Point 53 ARINC Lo L-CDU-1 JB1-F Pin 3J, 4A, 4C, 5A Test Point 56 ARINC Hi JB1-F Pin 3K, 4B, 4D, 5B Test Point 59 ARINC Lo |
RB-RIU-9, L-RIU-11, L-CDU-1 Bus |
| Air Conditioning | JB1-B Pin 15, 21, 19 Test Point 100 JB1-B Pin 17, 24, 22, 18 Test Point 102 JB1-B Pin 25, 26, 20 Test Point 89 |
N/A |
| Yaw Damper Actuator | JB1-F Pin 5C, 5K, 6A Test Point 35 | N/A |
Junction Box 1, Board 5
| System | Test Points: Discrete Black, ARINC Blue | Miscellaneous Equipment |
|---|---|---|
| Air Conditioning System, L Pressure Sensor | JB1-C Pin 5C, 5D, 5E, 5F, 5G, 5H, 5J, 5K Test Point 26 | N/A |
| AHRS Computer #1 | JB1-B Pin 1, 2, 3 Test Point 4 | N/A |
| General Radio Tunning | JB1-C Pin 1A, 2A, 1J, 1G, 1E, 2C, 1C Test Point 11 JB1-C Pin 1B, 2D, 2B, 1K, 1H, 1F, 1D Test Point 8 |
N/A |
| Cockpit Integral Lighting System | JB1-C Pin 3C, 3J, 3G, 3E Test Point 46 JB1-C Pin 3D, 3K, 3H, 3F Test Point 43 |
N/A |
| Fuel Distribution System Fuel Pump LHS | JB1-C Pin 4B, 5A, JB1-B Pin 13, JB1-B Pin 14 Test Point 5 JB1-C Pin 4E, 5B, JB1-C Pin 4E Test Point 2 K99 JB1-C Pin 4D (Relay X1) Test Point 38 JB1-C Pin 4C (Relay X2) Test Point 41 JB1-C Pin 4A (Relay B1) Test Point 47 JB1-C Pin 4F (Relay B2) Test Point 44 K100 JB1-C Pin 4J (Relay X1) Test Point 35 JB1-C Pin 4G, 4H (Relay X2) Test Point 29 JB1-C Pin 4J (Relay A2) Test Point 35 JB1-C Pin 4K (Relay A3) Test Point 32 |
Relay K99, K100 |
| General Radio Tunning Nav Left System | LA-RIU-7 JB1-C Pin 6B, 6D, 6F Test Point 23 ARINC Hi JB1-C Pin 6C, 6E, 6G Test Point 40 ARINC Lo LA-RIU-8 JB1-C Pin 6H, 6K, 7B Test Point 20 ARINC Hi JB1-C Pin 6J, 7A, 7C Test Point 37 ARINC Lo |
LA-RIU-7, LA-RIU-8 Bus |
| Electronic Flight Instrumentation System Bussing | JB1-C Pin 8K, 9B, 9D, 9F, 8F Test Point 13 ARINC Hi JB1-C Pin 9A, 9C, 9E, 9G, 8G, Test Point 16 ARINC Lo |
L-MFD-3 Bus |
| Horizontal Stab Trim Control System Power | JB1-B Pin 4, 5, 6, 10 Test Point 3 JB1-B Pin 7, 8, 9 Test Point 1 |
N/A |
| EICAS BRT/DIM Master Warning Caution System | JB1-C Pin 7D, 7E, 8B, 8C, 8D, 8E, 8H, 8J, 9H, 9J, 9K, 10A, 10E, 10F, 10G, 10H, 10J, 10K Test Point 10 | N/A |
| PMAT Connections between cards | ||
Junction Box JB2
Junction box JB2 is installed in a mounting tray in the RH equipment rack. The JB2 contains five circuit-cards. Each circuit-card is identified on its front side. The related circuit-card number is shown on the front face of the case.
Junction Box 2, Board 1
| System | Test Points: Discrete Black, ARINC Blue | Miscellaneous Equipment |
|---|---|---|
| Air Conditioning System Cross Bleed Valve | JB2-D Pin 7B, 7E, 7J Test Point 47 JB2-D Pin 7C, 7F, 7H Test Point 44 K10 JB2-D Pin 6C (Relay X1) Test Point 86 JB2-D Pin 7D (Relay X2) Test Point 75 JB2-D Pin 13J (Relay A1, B3) Test Point 81 JB2-D Pin 6C (Relay A2) Test Point 86 JB2-D Pin 13H (Relay A3, B1) Test Point 84 JB2-D Pin 6F (Relay B2) Test Point 85 JB2-D Pin 6E (Relay C2) Test Point 78 JB2-D Pin 7A (Relay C3) Test Point 50 JB2-D Pin 6D (Relay D2) Test Point 72 JB2-D Pin 7G (Relay D3) Test Point 53 K12 (Relay X1) Test Point 17 JB2-D Pin 6A (Relay X2) Test Point 1 (Relay A2) Test Point 4 JB2-D Pin 6C (Relay A2) Test Point 86 (Relay A3) Test Point 7 JB2-D Pin 6G (Relay B1) Test Point 13 JB2-D Pin 7D (Relay B2) Test Point 75 (Relay Y1) Test Point 20 JB2-D Pin 6A (Relay Y2) Test Point 1 K13 (Relay X1) Test Point 4 JB2-D Pin 6B (Relay X2) Test Point 28 (Relay B1) Test Point 20 JB2-D Pin 6C (Relay B2) Test Point 86 (Relay B3) Test Point 17 (Relay Y1) Test Point 7 JB2-D Pin 6B (Relay Y2) Test Point 28 |
Relays K10, K12, K13 |
| Terrain Avoidance & Warning Power & Indication | JB2-D Pin 7K, 8B, 8A, 8C Test Point 41 JB2-D Pin 8D Test Point 56 (CR34) JB2-D Pin 8F Test Point 59 (CR35) JB2-D Pin 8E Test Point 52 |
Diodes CR34, 35 |
| Ice Detection System Control | JB2-D Pin 9C, 9E, 9D Test Point 71 | N/A |
| Air Conditioning Right Bleed | JB2-D Pin 9G (Relay X1, B2) Test Point 19 JB2-D Pin 9H (Relay X2) Test Point 22 JB2-D Pin 9F, 9J (Relay B3) Test Point 25 |
Relay K68 |
| Global Position System Configuration | JB2-D Pin 14F, 14K, 14H Test Point 98 ARINC Hi JB2-D Pin 14G, 15A, 14J Test Point 101 ARINC Lo |
L-GPS-2 BUS |
| Air Conditioning System Right Pressure Sensor | JB2-E Pin 32, 30, 28, 26, 27, 29, 31, 33 Test Point 2 | N/A |
| Flight Management System | R-FMC-2 JB2-D Pin 15B, 15E, 15H Test Point 91 ARINC Hi JB2-D Pin 15C, 15F, 15J Test Point 94 ARINC Lo |
R-FMC-2 |
| Air Data Computer Signal O/P 2 | JB2-D Pin 11F, 11H, 11K Test Point 97 ARINC Hi JB2-D Pin 11G, 11J, 12A Test Point 100 ARINC Lo |
R-ADC-2 |
| EICAS DCU Interface | JB2-D Pin 12K, 12F, 12H Test Point 92 ARINC Hi JB2-D Pin 13A, 12G, 12J Test Point 95 ARINC Lo |
N/A |
| EICAS Power & Indication | JB2-E Pin 37, 38, 39, 40 Test Point 14 | N/A |
| EFIS Control | JB2-E Pin 41, 42, 43 Test Point 11 | N/A |
| Flap Power System | JB2-E Pin 54, 55, 56, 57, 58 Test Point 5 | K168 |
| Field Loadable Software, Air Data Computer, Data Download Switch | K158 JB2-E Pin 59 (Relay X1) Test Point 87 JB2-E Pin 60 (Relay X2) Test Point 49 JB2-D Pin 6K (Relay A1) Test Point 55 JB2-D Pin 6J (Relay A2) Test Point 52 JB2-D Pin 8G (Relay A3) Test Point 58 JB2-D Pin 8J (Relay B1) Test Point 61 JB2-D Pin 8H (Relay B2) Test Point 65 JB2-D Pin 10B (Relay C1) Test Point 83 JB2-D Pin 10A (Relay C2) Test Point 80 JB2-D Pin 10C (Relay C3) Test Point 67 JB2-D Pin 10E (Relay D1) Test Point 74 JB2-D Pin 10D (Relay D2) Test Point 77 JB2-D Pin 10F (Relay D3) Test Point 70 |
Relay K158 |
| Horizontal Stab Trim Control System Power | JB2-D Pin 11B, 11D, 12B Test Point 76 ARINC Hi JB2-D Pin 11C, 11E, 12C Test Point 79 ARINC Lo |
ARINC Information |
| Cabin Pressure System Outflow Valve | Out Flow Valve ARINC 1 JB2-D Pin 12D, 13B, 13D Test Point 93 ARINC Hi JB2-D Pin 12E, 13C, 13E Test Point 96 ARINC Lo Out Flow Valve ARINC 2 JB2-D Pin 13F, 13K, 14B, 14D Test Point 99 ARINC Hi JB2-D Pin 13G, 14A, 14C, 14E Test Point 102 ARINC Lo |
Dual Outflow ARINC Information |
Junction Box 2, Board 2
| System | Test Points: Discrete Black, ARINC Blue | Miscellaneous Equipment |
|---|---|---|
| Rudder Pedal Adjust | JB2-A Pin 11A, 11C, 11B Test Point 1 JB2-A Pin 11D, 11F, 11E Test Point 2 JB2-A Pin 11G, 11J, 11H Test Point 3 |
N/A |
| Fuel Computer System Refuel / De-fuel | JB2-A Pin 13B (Relay X1) Test Point 52 JB2-A Pin 13C (Relay X2) Test Point 58 JB2-A Pin 12G, 12H, 12K, 13A, 13E (Relay A1) Test Point 44 JB2-A Pin 12C, 12F (Relay A2) Test Point 46 JB2-A Pin 12D (Relay B1) Test Point 55 JB2-A Pin 12E (Relay B2) Test Point 49 JB2-A Pin 12J, 14E, 13D Test Point 31 JB2-A Pin 14D, 14C, 13F Test Point 37 JB2-A Pin 13J, 14A, 13G Test Point 40 JB2-A Pin 13K, 14B, 13H Test Point 34 |
Relay K1 |
| Flight Management System Bus Left | JB2-D Pin 3D, 3H, 4B Test Point 79 ARINC Hi JB2-D Pin 3E, 3J, 4C Test Point 82 ARINC Lo |
L-FMC-2 Bus |
| AHRS Computer #2 | JB2-E Pin 1, 3, 2 Test Point 7 | N/A |
| Interior Baseline Provisions | JB2-E Pin 7, 8, 9 Test Point 4 JB2-E Pin 10, 11 Test Point 12 |
N/A |
| Audio Integration System Copilot | JB2-A Pin 14K, 15B, 15A Test Point 13 JB2-A Pin 15C, 15E, 15D Test Point 10 |
N/A |
| Flight Management System | L-FMC-6 JB2-D Pin 1B, 1F, 2D Test Point 85 ARINC Hi JB2-D Pin 1C, 1G, 2E Test Point 88 ARINC Lo L-CDU-7 (Single FMS) R-CDU-6 (Dual FMS) JB2-D Pin 2B, 2F, 2H, 1D, 2K, 3B, 1H Test Point 80 ARINC Hi JB2-D Pin 2C, 2G, 2J, 1E, 3A, 3C, 1J Test Point 83 ARINC Lo |
L-FMC-6, L-CDU-7, R-CDU-6 |
| General Radio Tuning Nav Right System | RA-RIU-7 JB2-D Pin 4F, 4K, 4H Test Point 86 ARINC Hi JB2-D Pin 5A, 4G, 4J Test Point 89 ARINC Lo RA-RIU-8 JB2-D Pin 5B, 5H, 5E Test Point 81 ARINC Hi JB2-D Pin 5C, 5J, 5F Test Point 84 ARINC Lo |
RA-RIU-7, RA-RIU-8 Bus |
| Autopilot System Aileron Servo | JB2-A Pin 14J, 15F, 15G Test Point 8 | N/A |
| Cabin Pressure System Outflow Valve | JB2-A Pin 15H, 15J, 15K, JB2-D Pin 1A Test Point 5 | N/A |
| Audio Integration System Interconnect | RB-RIU-14 JB2-D Pin 1K, 3F, 3K, 4D Test Point 87 ARINC Hi JB2-D Pin 2A, 3G, 4A, 4E Test Point 90 ARINC Lo |
RB-RIU-14 Bus |
| Horizontal Stab Trim Control System | JB2-E Pin 4, 5, 6, 12 Test Point 11 | N/A |
| Reserved for DCP 692 | JB2-E Pin 13, 14, 15, 16 Test Point 20 | N/A |
| Autopilot System Power | JB2-E Pin 17, 18, 19, 20, 21, 22, 23 Test Point 17 | N/A |
| ISI Battery Test | JB2-E Pin 24 (Relay X1) Test Point 16 (Relay X2) Test Point 32 JB2-A Pin 14G (Relay A1) Test Point 43, JB2-A Pin 14F (Relay A1) Test Point 40 JB2-E Pin 25 (Relay A2, & B2) Test Point 19 JB2-A Pin 12A (Relay A3) Test Point 25 JB2-A Pin 12B (Relay B1) Test Point 23 JB2-A Pin 14H (Relay B3) Test Point 28 Several Pieces can be individually tested in the timing circuit, here is the list of additional test points. Resistor R1 Test Points 22 and 16 Zener Diode D1 Test Points 22 and 35 Resistor R2 Test Points 35 and 16 Resistor R3 Test Points 22, and 41 Diode D2 Test Points 22, and 38 |
Relay K157, Diodes, Resistors and Capacitors |
Junction Box 2, Board 3
| System | Test Points: Discrete Black, ARINC Blue | Miscellaneous Equipment |
|---|---|---|
| Cockpit Integral Lighting System | JB2-A Pin 1A, 1B, 1C Test Point 97 | N/A |
| Lightning Detection Option System Interface | JB2-A Pin 2K, 3A Test Point 1 (CR36 Anode) JB2-A Pin 3E, 3D Test Point 4 (CR36, CR13 Cathode) JB2-A Pin 3B, Test Point 2 (CR13, CR11 Anode) JB2-A Pin 3C Test Point 5 (CR11 Cathode) |
Diode check procedure |
| ATC 2 Transponder | JB2-A Pin 3F, 3G, 3H, 3J, 3K, 4A, 4B, 4C, 4D, 4E, 4F, 4G, 4H, 4J, 4K, 5A, 5B, 5C, 5D, 5E, 5F, 5G, 5H, 5J, 5K Test Point 3 | N/A |
| External Emergency Lighting System | JB2-B Pin 33, 34, 35 Test Point 10 JB2-B Pin 37, 39, 42 Test Point 8 JB2-B Pin 38, 40, 44 Test Point 17 |
N/A |
| Interior Baseline Provisions, Drain Mast Heaters Interface | JB2-E Pin 7, 8, 9 Test Point 4 JB2-E Pin 10, 11 Test Point 12 |
N/A |
| Audio Integration System Copilot | JB2-B Pin 45 (Relay K93, K95 X1, & B2) Test Point 35 JB2-B Pin 47 (Relay K93 X2) Test Point 31 JB2-B Pin 52 (Relay K93 A1) Test Point 34 JB2-B Pin 46 (Relay K93 A2) Test Point 37 JB2-B Pin 50 (Relay K93 B3) Test Point 28 JB2-B Pin 49 (Relay K95 X2) Test Point 38 JB2-B Pin 55 (Relay K95 A1) Test Point 41 JB2-B Pin 48 (Relay K95 A2) Test Point 39 JB2-B Pin 53 (Relay K95 B3) Test Point 43 |
Relay K93, K95 |
| EICAS DCU Interface | A-DCU-2 JB2-A Pin 6B, 6F, 6K, 6H, 6D Test Point 61 ARINC Hi JB2-A Pin 5C, 5G, 6E, 7A, 5J Test Point 64 ARINC Lo |
A-DCU-2 |
| EICAS RDC Interface | B-DCU-4 JB2-A Pin 8K, 9B, 9D, 9H, 9K Test Point 67 ARINC Hi JB2-A Pin 9A, 9C, 9E, 9J, 10A Test Point 70 ARINC Lo B-DCU-5 JB2-A Pin 9F, 10B, 10E Test Point 73 ARINC Hi JB2-A Pin 9G, 10C, 10F Test Point 76 ARINC Lo |
B-DCU-4, B-DCU-5 Bus |
| Integrated Avionics Processing System | R-GP-4 JB2-A Pin 7B, 7D, 7F, 7H, 7K, 8B, 8D, 8F, 8H Test Point 62 ARINC Hi JB2-A Pin 7E, 7G, 7C, 7J, 8A, 8C, 8E, 8G, 8J Test Point 65 ARINC Lo |
R-GP-4 |
| General Radio Tuning IAPS | R-CDU-1 JB2-A Pin 1D, 1H, 1K, 2F Test Point 68 ARINC Hi JB2-A Pin 1E, 1J, 2A, 2G Test Point 71 ARINC Lo L-RIU-12 JB2-A Pin 1F, 2B, 2D Test Point 74 ARINC Hi JB2-A Pin 1G, 2C, 2E Test Point 77 ARINC Lo |
R-CDU-1, L-RIU-12 |
| Pilot & Copilot Emergency Audio | JB2-A Pin 2H, 2J, 6A, 10H, 10J, 10K Test Point 7 | N/A |
Junction Box 2, Board 4
| System | Test Points: Discrete Black, ARINC Blue | Miscellaneous Equipment |
|---|---|---|
| Flight Data Recorder System | JB2-F Pin 1G, 1H, 1J Test Point 25 JB2-F Pin 1E, 1B, 1D, 2G (Relay K40 B2) Test Point 16 JB2-F Pin 1A, 1C (Relay K40 B3) Test Point 94 |
Relay K40 |
| Cockpit Voice Recorder System | JB2-B Pin 24, 23, (Relay K40, K41 X1) Test Point 85 JB2-B Pin 26 (Relay K40 X2) Test Point 91 JB2-B Pin 25 (Relay K41 X2) Test Point 100 JB2-B Pin 1F (Relay K41 A1) Test Point 97 (Relay K40 A1, Relay K41 A2) Test Point 99 JB2-F Pin 2F (Relay K40 A2) Test Point 13 JB2-B Pin 50 (Relay K93 B3) Test Point 28 JB2-B Pin 50 (Relay K93 B3) Test Point 28 |
Relay K40, K41 |
| Satellite Communications System | JB2-F Pin 2E (Relay K40, C2) Test Point 88 JB2-F Pin 2D (Relay K40, C3) Test Point 19 |
Relay K40 |
| Autopilot System Yaw Damper Actuator | JB2-F Pin 1K, 2B, 2A Test Point 22 JB2-F Pin 2C, 5D, 5E Test Point 10 |
N/A |
| Integrated Avionics Processing System | R-GP-1 JB2-F Pin 6B, 6D, 6F, 6H, 6K Test Point 49 ARINC Hi JB2-F Pin 6C, 6E, 6G, 6J, 7A Test Point 52 ARINC Lo |
R-GP-1 |
| Electrical Flight Instrumentation System Right PFD Bus | R-PFD-3 JB2-F Pin 7B, 7D, 7F, 8K Test Point 55 ARINC Hi JB2-F Pin 7C, 7E, 7G, 9A Test Point 58 ARINC Lo |
R-PFD-3 |
| Interior Baseline Provisions, Lighting Interface Electrical System | JB2-F Pin 3A (Relay X1) Test Point 90 JB2-F Pin 3B (Relay X2) Test Point 89 JB2-F Pin 2K (Relay A1) Test Point 86 JB2-F Pin 3C (Relay A2) Test Point 93 JB2-F Pin 2J (Relay A3) Test Point 87 |
Relay K110 |
| Interior | JB2-F Pin 3F (Relay K112 X1) Test Point 81 JB2-F Pin 3G (Relay K112 X2) Test Point 82 JB2-F Pin 3E (Relay K112 A1) Test Point 80 JB2-F Pin 3H (Relay K112 A2) Test Point 79 JB2-F Pin 3D (Relay K112 A3) Test Point 83 JB2-F Pin 5J (Relay K112 B1) Test Point 7 JB2-F Pin 2H (Relay K112 B2) Test Point 84 JB2-F Pin 5K (Relay K112 B3 (via R36)) Test Point 78 Relay K112 B3 (direct) Test Point 101 *JB2-F Pin 4A (Relay K114 X1) Test Point 76 *JB2-F Pin 4B (Relay K114 X2) Test Point 75 *JB2-F Pin 3K (Relay K114 A1) Test Point 77 *JB2-F Pin 4C (Relay K114 A2) Test Point 74 *JB2-F Pin 3J (Relay K114 A3) Test Point 73 *JB2-F Pin 4F (Relay K116 X1) Test Point 71 *JB2-F Pin 4G (Relay K116 X2) Test Point 69 *JB2-F Pin 4E (Relay K116 A1) Test Point 67 *JB2-F Pin 4H (Relay K116 A2) Test Point 56 *JB2-F Pin 4D (Relay K116 A3) Test Point 70 *JB2-F Pin 5A (Relay K118 X1) Test Point 54 *JB2-F Pin 5B (Relay K118 X2) Test Point 65 *JB2-F Pin 4K (Relay K118 A1) Test Point 55 *JB2-F Pin 5C (Relay K118 A2) Test Point 62 *JB2-F Pin 4J (Relay K118 A3) Test Point 51 |
Relay K112, R36 (*Spare Relays K114, K116, K118) |
| HF Communication System, Transceiver No. 2 | Analog Mic JB2-F Pin 8F, 8H, 7K Test Point 50 ARINC Hi JB2-F Pin 8G, 8J, 8A Test Point 53 ARINC Lo Analog Audio In JB2-F Pin 8B, 8D, 7H Test Point 56 ARINC Hi JB2-F Pin 8C, 8E, 7J Test Point 59 ARINC Lo |
N/A |
| Integrated Avionics Processing System | R-IOC-1 JB2-F Pin 9H, 9K, 10B, 10E, 10H Test Point 51 ARINC Hi JB2-F Pin 9J, 10A, 10C, 10F, 10J Test Point 54 ARINC Lo |
R-IOC-1 |
Junction Box 2, Board 5
| System | Test Points: Discrete Black, ARINC Blue | Miscellaneous Equipment |
|---|---|---|
| Interior Baseline Provisions Exterior Lighting Interface | JB2-C Pin 3G, 3H, 3F Test Point 1 | N/A |
| Integrated Avionics Processing | L-GP-5 JB2-C Pin 3J, 4A, 4C, 4E, 4J, 4G, 5B, 5D, 5F Test Point 2 ARINC Hi JB2-C Pin 3K, 4B, 4D, 4F, 4H, 5A, 5C, 5E, 5H Test Point 3 ARINC Lo |
L-GP-5 |
| Engine ID & Secondary Systems Selection Data Right | RA-FADEC-1 JB2-C Pin 7K, 8B, 8F, 8D, 8H, 8K Test Point 4 ARINC Hi JB2-C Pin 8A, 8C, 8G, 8E, 8J, 9A Test Point 5 ARINC Lo |
RA-FADEC-1 |
| Engine ID & Secondary Systems Selection Data Right | JB2-B Pin 1, 2, 3, 4 Test Point 6 | N/A |
| General Radio Tuning Emergency Frequency Selection | JB2-B Pin 5, 8, 11, 13 Test Point 7 JB2-B Pin 6, 9, 12, 15 Test Point 8 JB2-B Pin 7, 10, 14 Test Point 9 |
N/A |
| PMAT Connections between cards | ||
Junction Box JB3
Junction box JB3 is installed in a mounting tray in the LH equipment rack. The JB3 contains five circuit-cards. Each circuit-card is identified on its front side. The related circuit-card number is shown on the front face of the case.
Junction Box 3, Board 1
| System | Test Points: Discrete Black, ARINC Blue | Miscellaneous Equipment |
|---|---|---|
| Interior | JB3-D Pin 6C (Relay K121 X1) Test Point 7 JB3-D Pin 6D (Relay K121 X2) Test Point 5 JB3-D Pin 6B (Relay K121 A1) Test Point 10 JB3-D Pin 6E (Relay K121 A2) Test Point 2 JB3-D Pin 6A (Relay K121 A3) Test Point 16 *JB3-D Pin 6H (Relay K123 X1) Test Point 13 *JB3-D Pin 6J (Relay K123 X2) Test Point 17 *JB3-D Pin 6G (Relay K123 A1) Test Point 20 *JB3-D Pin 6K (Relay K123 A2) Test Point 24 *JB3-D Pin 6F (Relay K123 A3) Test Point 21 *JB3-D Pin 8C (Relay K125 X1) Test Point 39 *JB3-D Pin 8D (Relay K125 X2) Test Point 42 *JB3-D Pin 8B (Relay K125 A1) Test Point 40 *JB3-D Pin 8E (Relay K125 A2) Test Point 37 *JB3-D Pin 7A (Relay K125 A3) Test Point 41 *JB3-D Pin 8H (Relay K127 X1) Test Point 54 *JB3-D Pin 8J (Relay K127 X2) Test Point 57 *JB3-D Pin 8G (Relay K127 A1) Test Point 52 *JB3-D Pin 8K (Relay K127 A2) Test Point 55 *JB3-D Pin 8F (Relay K127 A3) Test Point 59 *JB3-D Pin 9C (Relay K129 X1) Test Point 66 *JB3-D Pin 9D (Relay K129 X2) Test Point 68 *JB3-D Pin 9B (Relay K129 A1) Test Point 65 *JB3-D Pin 9E (Relay K129 A2) Test Point 69 *JB3-D Pin 9A (Relay K129 A3) Test Point 63 |
Relays K121, *Spare Relays K123, K125, K127, K129 (not installed (unpopulated sockets)) |
| Fidex System Firex | JB3-E Pin 26, 27, 29 Test Point 12 JB3-E Pin 31, 28, 30 Test Point 9 |
N/A |
| Aileron Electrical System Power & Control | JB3-D Pin 7H (Relay K55 X1) Test Point 83 JB3-D Pin 7C, JB3-E Pin 39, 42 (Relay K55 X2) Test Point 77 JB3-D Pin 7E (Relay K55 A1) Test Point 80 JB3-D Pin 15B (Relay K55/K52 A2) Test Point 85 JB3-D Pin 7G (Relay K55 B1) Test Point 84 JB3-D Pin 15C (Relay K55/K52 B2) Test Point 87 JB3-D Pin 7F (Relay K55 C1) Test Point 81 JB3-D Pin 15D (Relay K55/K52 C2) Test Point 82 JB3-E Pin 59 (Relay K55 D1) Test Point 78 JB3-D Pin 7B (Relay K55 D2) Test Point 79 JB3-D Pin 7H (Relay K52 X1) Test Point 83 JB3-D Pin 7C 9K, 9G (Relay K52 X2) Test Point 74 JB3-D Pin 7E (Relay K52 A1) Test Point 80 JB3-D Pin 15B (Relay K52 A2) Test Point 85 JB3-D Pin 7G (Relay K52 B1) Test Point 84 JB3-D Pin 15C (Relay K52 B2) Test Point 87 JB3-D Pin 7F (Relay K52 C1) Test Point 81 JB3-D Pin 15D (Relay K52 C2) Test Point 82 JB3-E Pin 60 (Relay K52 D1) Test Point 75 JB3-D Pin 8A (Relay K52 D2) Test Point 71 |
Relay K52, K55 |
| Horizontal Stab Trim Control System Cockpit | JB3-D Pin 9F, 9J, 10B Test Point 64 JB3-D Pin 9H, 10A, 10C Test Point 67 JB3-D Pin 7D, 9K, 9G Test Point 74 JB3-E Pin 36, 38, 41 Test Point 6 JB3-E Pin 37, 40, 43 Test Point 3 JB3-E Pin 39, 42, JB3-D Pin 7C Test Point 77 |
N/A |
| Air Data Computer Signal O/P 1 | JB3-D Pin 11B, 15H, 15E Test Point 98 ARINC Hi JB3-D Pin 11C, 15J, 15F Test Point 101 ARINC Lo |
L-ADC-2 Bus |
| General Radio Tuning Nav Left System | LB-RIU-7 JB3-D Pin 11D, 11F, 11H Test Point 93 ARINC Hi JB3-D Pin 11E, 11G, 11J Test Point 96 ARINC Lo LB-RIU-8 JB3-D Pin 11K, 12B, 12D Test Point 99 ARINC Hi JB3-D Pin 12A, 12C, 12E Test Point 102 ARINC Lo |
LB-RIU-7, LB-RIU-8 Bus |
| General Radio Tuning Display Left System | LB-RIU-6 JB3-D Pin 13B, 12F, 12H, 12K, 14K Test Point 91 ARINC Hi JB3-D Pin 13C, 12G, 12J, 13A, 15A Test Point 94 ARINC Lo |
LB-RIU-6 Bus |
| IASC Bus Interface | JB1-D Pin 13F, 13H, 13D Test Point 97 ARINC Hi JB1-D Pin 13G, 13J, 13E Test Point 100 ARINC Lo |
IASC1-A Bus |
| EICAS Brt/Dim Power Supplies System | JB3-E Pin 35 Test Point 18 JB3-E Pin E33 (via R11) Test Point 18 JB3-E Pin E34 (via R12) Test Point 18 |
Resistor R11, R12 |
| Electronic Flight Instrumentation System Right MFD Bussing | JB3-E Pin 44, 46, 48, 50, 52 Test Point 92 ARINC Hi JB3-E Pin 45, 47, 49, 51, 53 Test Point 95 ARINC Lo |
R-MFD-3 Bus |
| EICAS RDC to Display Interface | JB3-D Pin 13K, 14B, 14D, 14F, 14H Test Point 85 ARINC Hi JB3-D Pin 14A, 14C, 14E, 14G, 14J Test Point 88 ARINC Lo |
Bus |
| FMS Database Option | JB3-D Pin 10F, 10G, 10H, 10J, 10K, 11A Test Point 73 | N/A |
Junction Box 3, Board 2
| System | Test Points: Discrete Black, ARINC Blue | Miscellaneous Equipment |
|---|---|---|
| Air Conditioning | JB3-A Pin 11K, 12E (Relay K97 X1) Test Point 40 JB3-A Pin 14C, 12C (Relay K97 X2) Test Point 29 JB3-D Pin 3F (Relay K97 A1) Test Point 61 JB3-D Pin 3D (Relay K97 A2) Test Point 55 JB3-D Pin 3C (Relay K97 A3) Test Point 52 JB3-D Pin 3G (Relay K97 B1) Test Point 64 JB3-D Pin 3E (Relay K97 B2) Test Point 37 JB3-D Pin 3B (Relay K97 B3) Test Point 49 JB3-D Pin 12B (Relay K97 C1) Test Point 33 JB3-A Pin 13K (Relay K97 C2) Test Point 32 JB3-A Pin 12A (Relay K97 C3) Test Point 36 JB3-A Pin 13D, 14D (Relay K97 D1) Test Point 30 JB3-A Pin 13J (Relay K97 D2) Test Point 34 |
Relay K97 |
| Air Conditioning System Cross Over Cool Valve | JB3-A Pin 11K, 12E (Relay K14 X1, A2) Test Point 40 JB3-A Pin 13A (Relay K14 X2, A2) Test Point 96 JB3-A Pin 13C (Relay K14 A1, B3) Test Point 76 JB3-A Pin 13B (Relay K14 A3, B1) Test Point 77 JB3-A Pin 12D (Relay K14 B2) Test Point 93 |
Relay K14 |
| Air Conditioning | JB3-A Pin 13E, 14E, JB3-E Pin 23 Test Point 6 JB3-A Pin 13H, 14H, JB3-E Pin 22 Test Point 9 JB3-A Pin 13G, 14A, 14G, Test Point 100 JB3-A Pin 13F, 14B, 14F Test Point 101 |
N/A |
| Traffic Collision Avoidance System Interface | JB3-A Pin 15B, 15C, 15D, 15E, 15F Test Point 97 | N/A |
| Lighting Interface System | JB3-A Pin 14J, 14K, 15A Test Point 98 | N/A |
| Flight Management System | JB3-D Pin 3H, 4A, 4C, 4E, 4G, 4J, 5A, 5C Test Point 79 ARINC Hi JB3-D Pin 3J, 3K, 4B, 4D, 4F, 4H, 4K, 5B Test Point 82 ARINC Lo |
L-CDU-6 Bus |
| Fidex System Power | JB3-E Pin 1, 2, 3, 7 Test Point 19 | N/A |
| Cabin Pressure | JB3-E Pin 21 (Relay X1, A1) Test Point 13 JB3-E Pin 8 (Relay X2) Test Point 18 JB3-A Pin 12G (Relay A2, B2) Test Point 17 JB3-A Pin 12F (Relay B3) Test Point 27 JB3-A Pin 15G, 15H, 15J Test Point 95 |
Relay K150 |
| Cabin Pressure | JB3-E Pin 19 (Relay K85 X1) Test Point 24 JB3-E Pin 18 (Relay K85 X2) Test Point 12 (Relay K85 A2, C2) Test Point 10 JB3-D Pin 1C (Relay K85 A3) Test Point 21 (Relay K85 B2, D2) Test Point 7 JB3-D Pin 1B (Relay K85 B3) Test Point 15 JB3-E Pin 20 (Relay K85 C1) Test Point 4 JB3-A Pin 12G (Relay K85 D1) Test Point 17 JB3-E Pin 12J (Relay K86 X1) Test Point 43 JB3-E Pin 12H (Relay K86 X2) Test Point 23 JB3-D Pin 1E (Relay K86 A2, C2) Test Point 46 (Relay K86 A3) Test Point 10 JB3-D Pin 1D (Relay K86 B2, D2) Test Point 31 JB3-A Pin 12G (Relay K86 C1) Test Point 17 JB3-A Pin 12K (Relay K86 D1) Test Point 20 |
Relay K85, K86 |
| Air Conditioning System Avionics Cooling | JB3-D Pin 5E, 5F, 5G Test Point 28 | N/A |
| Fidex System Firex Bottle 1 | JB3-E Pin 9, 12, 13 Test Point 16 JB3-E Pin 10, 11, 16 Test Point 8 JB3-E Pin 14, 15, 17 Test Point 11 |
N/A |
| Anti Ice System, Low Temp Indication | JB3-D Pin 5H, 5J, 5K Test Point 25 | N/A |
Junction Box 3, Board 3
| System | Test Points: Discrete Black, ARINC Blue | Miscellaneous Equipment |
|---|---|---|
| Audio Integration System Pilot | JB3-A Pin 1D, 1E, 1F Test Point 94 | N/A |
| ATC Control Display System | JB3-A Pin 4A, 4B, 4C, 4D Test Point 85 | N/A |
| Air Data Sensor Heater | JB3-A Pin 3B, 3C, 3D Test Point 91 JB3-B Pin 42, 43, 44 Test Point 4 |
N/A |
| Air Conditioning System Cross Over Cool Valve | JB3-A Pin 3E, 4J, 5A Test Point 82 JB3-A Pin 3F, 4K, 5B Test Point 92 |
N/A |
| Satellite Communication Electrical System Control | JB3-A Pin 6D, 6F, 6K Test Point 61 ARINC Hi JB3-A Pin 6E, 6G, 7A Test Point 64 ARINC Lo |
SATCOMM-M Bus |
| Integrated Avionics Processing System | JB3-A Pin 7F, 7H, 7K, 8B, 8D, 8H Test Point 62 ARINC Hi JB3-A Pin 7G, 7J, 8A, 8C, 8E, 8J Test Point 65 ARINC Lo |
R-GP-5 Bus |
| Air Conditioning System Avionics Cooling | JB3-A Pin 4F, 4G, 5D, 5E Test Point 89 | N/A |
| Data Load FMS | JB3-A Pin 5F, 5G, 5H, 5J, 5K, 6A Test Point 2 | N/A |
| Integrated Standby Instrument Electrical System | JB3-A Pin 6B, 6H, 7B, 7D, 8F Test Point 68 ARINC Hi JB3-A Pin 6C, 6J, 7C, 7E, 8G Test Point 71 ARINC Lo |
ISI-1 Bus |
| Integrated Avionics Processing System | JB3-A Pin 10B, 10E, 10H Test Point 44 ARINC Hi JB3-A Pin 10C, 10F, 10J Test Point 47 ARINC Lo |
R-GP-5 Bus |
| Horizontal Stab Trim Control System Cockpit | JB3-B Pin 31, 32, 33, 34 Test Point 1 | N/A |
| EICAS Power & Indication | JB3-B Pin 38, 39, 40, 41 Test Point 10 | N/A |
| Pilot / CoPilot Emergency Audio | JB3-B Pin 45, 46, 47, 48 Test Point 7 | N/A |
| K174 | JB3-B Pin 49 (Relay X1) Test Point 24 JB3-B Pin 50 (Relay X2) Test Point 19 JB3-A Pin 2B (Relay A1) Test Point 28 JB3-A Pin 1K (Relay A2) Test Point 26 JB3-A Pin 2C (Relay A3) Test Point 13 JB3-A Pin 2D (Relay B1) Test Point 25 JB3-A Pin 2A (Relay B2) Test Point 3 JB3-A Pin 2E (Relay B3) Test Point 31 |
K174 |
| K175 | JB3-B Pin 51 (Relay X1) Test Point 37 JB3-B Pin 52 (Relay X2) Test Point 52 JB3-A Pin 2J (Relay A1) Test Point 43 JB3-A Pin 2F (Relay A2) Test Point 40 JB3-A Pin 2K (Relay A3) Test Point 34 JB3-A Pin 3A (Relay B1) Test Point 46 JB3-A Pin 2G (Relay B2) Test Point 49 JB3-A Pin 1J (Relay B3) Test Point 55 |
K175 |
Junction Box 3, Board 4
| System | Test Points: Discrete Black, ARINC Blue | Miscellaneous Equipment |
|---|---|---|
| Engine ID and Secondary Systems Selection Data Left | JB3-F Pin 6H, 6K, 7B, 7D, 7F, 7H Test Point 49 ARINC Hi JB3-F Pin 6J, 7A, 7C, 7E, 7G, 7J Test Point 52 ARINC Lo |
LB-FADEC-1 Bus |
| TCAS Power and Control | JB3-F Pin 5A, 5B, 5C Test Point 9 JB3-F Pin 6B, 6D, 6F Test Point 55 ARINC Hi JB3-F Pin 6C, 6E, 6G Test Point 58 ARINC Lo |
TTR-TR/TA-1 |
| EICAS RDC to Display Interface | JB3-F Pin 7K, 8B, 8D, 8F, 8H Test Point 50 ARINC Hi JB3-F Pin 8A, 8C, 8E, 8G, 8J Test Point 53 ARINC Lo |
Bus |
| Anti-Ice High Pressure Sensors and Air Conditioning L Pressure and Vent Temperature Sensors | JB3-F Pin 5H, 5J, 5K, 6A Test Point 3 | N/A |
| Flap System Load Sense Pin FCU Excite | JB3-F Pin 8K, 9B, 9D, 9F, 9H, 9K Test Point 56 ARINC Hi JB3-F Pin 9A, 9C, 9E, 9G, 9J, 10A Test Point 59 ARINC Lo |
Bus |
| Flap Alternate Power | JB3-B Pin 16 (Relay X1) Test Point 94 JB3-F Pin 17 (Relay X2) Test Point 98 JB3-F Pin 1F (Relay A1) Test Point 100 JB3-F Pin 1D (Relay A2) Test Point 97 JB3-F Pin 1G (Relay A3) Test Point 91 JB3-F Pin 1H (Relay B1) Test Point 93 JB3-F Pin 1E (Relay B2) Test Point 96 JB3-F Pin 1J (Relay B3) Test Point 101 |
Relay K168 |
| Master Disconnect Horizontal, Aileron, & Rudder Trim Systems | JB3-F Pin 4B (Relay X1) Test Point 34 JB3-F Pin 4A (Relay X2) Test Point 71 JB3-F Pin 3E (Relay A2) Test Point 37 JB3-F Pin 3C (Relay A3) Test Point 68 JB3-F Pin 3K (Relay B1) Test Point 43 JB3-F Pin 3D (Relay B2) Test Point 40 JB3-F Pin 3B (Relay B3) Test Point 73 JB3-F Pin 3G (Relay C2) Test Point 69 JB3-F Pin 3F (Relay C3) Test Point 74 JB3-F Pin 3H (Relay D2) Test Point 72 JB3-F Pin 3J (Relay D3) Test Point 75 |
Relay K89 |
| Rudder Trim Control System | JB3-F Pin 4G, 4C, Test Point 31 JB3-F Pin 4H, 4D Test Point 19 JB3-F Pin 4J, 4F Test Point 28 |
N/A |
Junction Box 3, Board 5
| System | Test Points: Discrete Black, ARINC Blue | Miscellaneous Equipment |
|---|---|---|
| Auto Pilot, Stall Protection Monitoring, and Master Disconnect | JB3-B Pin 5, 10 (Relay X1) Test Point 18 JB3-C Pin 5J (Relay X2) Test Point 29 JB3-B Pin 1 (Relay A1) Test Point 6 JB3-B Pin 2 (Relay A2) Test Point 2 JB3-B Pin 3 (Relay B1) Test Point 5 JB3-B Pin 4 (Relay B2) Test Point 15 JB3-B Pin 6 (Relay C2) Test Point 12 JB3-B Pin 8 (Relay C3) Test Point 1 JB3-B Pin 7 (Relay D2) Test Point 9 JB3-B Pin 9 (Relay D3) Test Point 3 |
Relay 87 |
| Flight Management System | JB3-C Pin 2J (Relay X1, A2) Test Point 42 JB3-C Pin 3B, 3D (Relay X2) Test Point 48 JB3-C Pin 3A, 3C (Relay A1) Test Point 45 JB3-C Pin 2K (Relay A3) Test Point 39 JB3-C Pin 6K, 7H, 6B, 8F Test Point 22 ARINC Hi JB3-C Pin 7A, 7J, 6C, 8G Test Point 23 ARINC Lo JB3-C Pin 7B, 7K, 6D, 8H Test Point 19 ARINC Hi JB3-C Pin 7C, 8A, 6E, 8J Test Point 20 ARINC Lo JB3-C Pin 7D, 8B, 6F, 8K Test Point 10 JB3-C Pin 7E, 8C, 6G, 9A Test Point 7 JB3-C Pin 7F, 8D, 5H, 9B Test Point 13 JB3-C Pin 7G, 8E, 6J, 9C Test Point 16 |
Relay K136, L-FMC-5 Bus |
| EICAS Brt / Dim Pedestal Interface | JB3-C Pin 3K (CR38 Anode) Test Point 44 JB3-C Pin 4A (CR38 Cathode) Test Point 47 |
|
| Rudder Pedal Force Position Sensor | JB3-C Pin 4B, 4C, 4D, 4E Test Point 41 | N/A |
| Electronic Flight Instrumentation System Reversion | JB3-C Pin 5A, 5B, 5C, Test Point 38 JB3-C Pin 5D, 5E, 5F Test Point 26 |
|
| Stall Protection Power Supply Electrical System | A-SPC-1 JB3-C Pin 9D, 9H, 9F Test Point 4 ARINC Hi JB3-C Pin 9E, 9J, 9G Test Point 17 ARINC Lo |
A-SPC-1 Bus |
| Air Data Computer | JB3-C Pin 9K, 10B, 10E Test Point 11 ARINC Hi JB3-C Pin 10A, 10C, 10F Test Point 14 ARINC Lo |
R-ADC-3 |
| PMAT Connections between cards | ||
Junction Box JB4
Junction box JB4 is installed in a mounting tray in the RH equipment rack. The JB4 contains five circuit-cards. Each circuit-card is identified on its front side. The related circuit-card number is shown on the front face of the case.
Junction Box 4, Board 1
| System | Test Points: Discrete Black, ARINC Blue | Miscellaneous Equipment |
|---|---|---|
| Interior | JB4-D Pin 6C (Relay K120 X1) Test Point 1 JB4-D Pin 6D (Relay K120 X2) Test Point 4 JB4-D Pin 6B (Relay K120 A1) Test Point 16 JB4-D Pin 6E (Relay K120 A2) Test Point 5 JB4-D Pin 6A (Relay K120 A3) Test Point 6 JB4-D Pin 6H (Relay K122 X1) Test Point 32 JB4-D Pin 6J (Relay K122 X2) Test Point 23 JB4-D Pin 6G (Relay K122 A1) Test Point 29 JB4-D Pin 6K (Relay K122 A2) Test Point 26 JB4-D Pin 6F (Relay K122 A3) Test Point 15 JB4-D Pin 7C (Relay K124 X1) Test Point 19 JB4-D Pin 7D (Relay K124 X2) Test Point 22 JB4-D Pin 7B (Relay K124 A1) Test Point 31 JB4-D Pin 7E (Relay K124 A2) Test Point 25 JB4-D Pin 7A (Relay K124 A3) Test Point 35 JB4-D Pin 7H (Relay K126 X1) Test Point 38 JB4-D Pin 7J (Relay K126 X2) Test Point 37 JB4-D Pin 7G (Relay K126 A1) Test Point 21 JB4-D Pin 7K (Relay K126 A2) Test Point 34 JB4-D Pin 7F (Relay K126 A3) Test Point 28 JB4-D Pin 8C (Relay K128 X1) Test Point 43 JB4-D Pin 8D (Relay K128 X2) Test Point 61 JB4-D Pin 8B (Relay K128 A1) Test Point 55 JB4-D Pin 8E (Relay K128 A2) Test Point 58 JB4-D Pin 8A (Relay K128 A3) Test Point 40 |
Relay K120, 122, 124, 126, 128 |
| Fidex System Bottle 2 - APU | JB4-E Pin 52, 53, 54 Test Point 2 JB4-E Pin 55, 56, 60 Test Point 3 JB4-E Pin 58, 57, 59 Test Point 7 |
N/A |
| Integrated Avionics Processing System (IOC) | JB4-D Pin 13K, 14B, 14D, 14F, 14H Test Point 91 ARINC Hi JB4-D Pin 14A, 14C, 14E, 14G, 14J Test Point 94 ARINC Lo |
L-IOC-1 Bus |
| Integrated Avionics Processing System | JB4-D Pin 11D, 11F, 11H, 11K, 12B Test Point 97 ARINC Hi JB4-D Pin 11E, 11G, 11J, 12C, 12A Test Point 100 ARINC Lo |
L-GP-1 Bus |
| Fidex System Bottle 1 | JB4-E Pin 29, 30, 31 Test Point 17 JB4-E Pin 32, 34, 40 Test Point 14 JB4-E Pin 33, 37, 39 Test Point 11 JB4-E Pin 35, 36, 38 Test Point 8 |
N/A |
| Interior Baseline Provisions Exterior Lighting Interface | JB4-E Pin 44, 45, 46 Test Point 10 | N/A |
| EICAS Brt/Dim Power Supply System | JB4-E Pin 51 Test Point 9 | Resistor R9, R10 |
| Horizontal Stab Trim Control System Power | JB4-E Pin 41, 42, 43 Test Point 13 | N/A |
| ATC Control Display System | JB4-D Pin 9B, 9C, 9D, 9E Test Point 70 | N/A |
| Cabin Pressure System | JB4-D Pin 9A (Relay K142 X1, A1) Test Point 54 JB4-D Pin 8K (Relay K142 X2) Test Point 49 JB4-D Pin 8H, 8G (Relay K142 A2, B2) Test Point 52 JB4-D Pin 8J (Relay K142 B3) Test Point 45 |
Relay K142 |
| General Radio Tuning Reversion Select System | JB4-D Pin 9H, 9K, 10B, 10D, 10F, 10H Test Point 82 JB4-D Pin 9J, 10A, 10C, 10E, 10G, 10J Test Point 85 |
N/A |
| Integrated Avionics Processing System | JB4-D Pin 12D, 12F, 12H, 12K, 13B, 13D, 13F, 13H Test Point 92 ARINC Hi JB4-D Pin 12E, 12G, 12J, 13A, 13C, 13E, 13G, 13J Test Point 95 ARINC Lo |
L-GP-4 Bus |
| Integrated Avionics Processing PMAT MDC | JB4-D Pin 11B, 14K, 15B, 15E, 15H Test Point 98 ARINC Hi JB4-D Pin 11C, 15A, 15C, 15F, 15J Test Point 101 ARINC Lo |
DBU-3 Bus |
| Interior Baseline Provisions Wast Disposal Electric Heated Plumbing | JB4-E Pin 26, 27, 28, 47, 48 Test Point 20 | N/A |
Junction Box 4, Board 2
| System | Test Points: Discrete Black, ARINC Blue | Miscellaneous Equipment |
|---|---|---|
| Ice Detection System Control | JB4-A Pin 11A, 11B, 11C Test Point 45 | N/A |
| EICAS Power & Indication | JB4-A Pin 11G, 11H, 11J, 11K Test Point 55 JB4-A Pin 12A, 12B, 12C, 12D Test Point 99 JB4-A Pin 12E, 12F, 12G, 12H Test Point 102 |
N/A |
| Cabin Pressure System Power & Control | JB4-A Pin 12K, 13A, 13B, 13C Test Point 101 | N/A |
| AutoPilot System Yaw Damper Actuator | JB4-A Pin 13D, 13E, 13F, 13G Test Point 100 | N/A |
| Proximity Sensing Landing Gear Control | JB4-E Pin 23 (Relay K50 X1) Test Point 43 JB4-E Pin 19 (Relay K50 X2) Test Point 35 JB4-E Pin 12 (Relay K50 A1) Test Point 67 JB4-E Pin 1 (Relay K50 A2) Test Point 61 JB4-E Pin 11 (Relay K50 A3) Test Point 40 JB4-E Pin 10 (Relay K50 B1) Test Point 64 JB4-E Pin 2 (Relay K50 B2) Test Point 58 JB4-E Pin 9 (Relay K50 B3) Test Point 37 JB4-E Pin 8 (Relay K50 C1) Test Point 49 JB4-E Pin 3 (Relay K50 C2) Test Point 38 JB4-E Pin 7 (Relay K50 C3) Test Point 34 JB4-E Pin 6 (Relay K50 D1) Test Point 25 JB4-E Pin 4 (Relay K50 D2) Test Point 28 JB4-E Pin 5 (Relay K50 D3) Test Point 31 JB4-E Pin 25 (Relay K51 X1) Test Point 8 JB4-E Pin 20 (Relay K51 X2) Test Point 19 JB4-E Pin 18 (Relay K51 A1) Test Point 7 JB4-E Pin 13 (Relay K51 A2) Test Point 5 JB4-E Pin 17 (Relay K51 A3) Test Point 4 JB4-E Pin 16 (Relay K51 B1) Test Point 13 JB4-E Pin 14 (Relay K51 B2) Test Point 16 JB4-E Pin 15 (Relay K51 B3) Test Point 22 JB4-A Pin 11D, 13J, 14C Test Point 1 JB4-A Pin 11E, 13K, 14D Test Point 2 JB4-A Pin 11F, 14E, 14A Test Point 3 JB4-A Pin 13H, 14B, 14F Test Point 98 |
Relay K50, K51 |
| General Radio Tuning Nav Right System | RB-RIU-7 JB4-D Pin 1B, 1D, 1F Test Point 79 ARINC Hi JB4-D Pin 1C, 1E, 1G Test Point 82 ARINC Lo RB-RIU-8 JB4-D Pin 1H, 1K, 2B Test Point 85 ARINC Hi JB4-D Pin 1J, 2A, 2C Test Point 88 ARINC Lo |
RB-RIU-7, RB-RIU-8 Bus |
| General Radio Tuning Displays Left System | JB4-D Pin 2H, 2D, 2F, 4H Test Point 80 ARINC Hi JB4-D Pin 2J, 2E, 2G, 4J Test Point 83 ARINC Lo |
LB-RIU-9 Bus |
| EICAS RDC Interface | A-DCU-4 JB4-D Pin 3B, 3D, 3F, 4B, 4D, 4F Test Point 81 ARINC Hi JB4-D Pin 3C, 3E, 3G, 4C, 4E, 4G Test Point 84 ARINC Lo A-DCU-5 JB4-D Pin 2K, 3K, 3J Test Point 86 ARINC Hi JB4-D Pin 3A, 4A, 3H Test Point 89 ARINC Lo |
A-DCU-4, A-DCU-5 |
| Cabin Pressure System | JB4-E Pin 21 (Relay X1) Test Point 73 JB4-E Pin 22 (Relay X2) Test Point 70 JB4-A Pin 15H (Relay A2) Test Point 52 JB4-A Pin 15J (Relay A3) Test Point 91 |
Relay K152 |
| Integrated Avionics Processing System PMAT & MDC | JB4-D Pin 4K, 5B, 5E, 5H Test Point 87 ARINC Hi JB4-D Pin 5A, 5C, 5F, 5J Test Point 90 ARINC Lo |
MDC-6 Bus |
Junction Box 4, Board 3
| System | Test Points: Discrete Black, ARINC Blue | Miscellaneous Equipment |
|---|---|---|
| EICAS DCU Interface | JB4-A Pin 7K, 8B, 8D, 8H, 8F Test Point 51 ARINC Hi JB4-D Pin 8A, 8C, 8E, 8J, 8G Test Point 64 ARINC Lo |
B-DCU-2 |
| Integrated Avionics Processing System | JB4-A Pin 6B, 6D, 6F, 6K, 6H, 7B, 7D, 7F, 7H Test Point 67 ARINC Hi JB4-D Pin 6C, 6E, 6G, 6J, 7A, 7C, 7E, 7G, 7J Test Point 70 ARINC Lo |
R-GP-5 |
| Engine ID & Secondary Systems Selections Data Right | JB4-A Pin 8K, 9B, 9D, 9F, 9H, 9K Test Point 73 ARINC Hi JB4-A Pin 9A, 9C, 9E, 9G, 9J, 10A Test Point 76 ARINC Lo |
RB-FADEC-1 |
| Brake Control System & PSEU Interface | JB4-B Pin 36, 38, 39 Test Point 3 JB4-B Pin 37, 40 Test Point 2 |
N/A |
| Inter grated Avionics Processing System PMAT MDC | MDC-3 JB4-A Pin 4F, 4B, 5B Test Point 74 ARINC Hi JB4-A Pin 4G, 4C, 5C Test Point 77 ARINC Lo PMAT-3 JB4-A Pin 4H, 4D, 5D Test Point 74 ARINC Hi JB4-A Pin 4J, 4E, 5E Test Point 66 ARINC Lo |
MDC-3, PMAT-3 Bus |
| Fuel Distribution System | JB4-A Pin 1D (Relay K102 X1) Test Point 37 JB4-A Pin 1C (Relay K102 X2) Test Point 40 JB4-A Pin 1A (Relay K102 B1) Test Point 10 JB4-A Pin 1F (Relay K102 B2) Test Point 9 JB4-A Pin 1J (Relay K103 X1, A2) Test Point 53 JB4-A Pin 1G, 1H (Relay K103 X2) Test Point 55 JB4-A Pin 1K (Relay K103 A3) Test Point 34 JB4-A Pin 1F (Relay K105 X1, B2) Test Point 9 JB4-A Pin 2C (Relay K105 X2) Test Point 11 JB4-A Pin 2D (Relay K105 A1) Test Point 13 JB4-A Pin 2B (Relay K105 A2) Test Point 12 JB4-A Pin 1A (Relay K105 B1) Test Point 10 JB4-A Pin 2A, 1B, 2F, 2G Test Point 94 JB4-A Pin 2E, 1E, 2H Test Point 4 |
Relay K102, 103, 105 |
| EICAS Power & Indication | JB4-A Pin 6A, 5G, 5H, 5J, 5K Test Point 1 | N/A |
Junction Box 4, Board 4
| System | Test Points: Discrete Black, ARINC Blue | Miscellaneous Equipment |
|---|---|---|
| Oxygen System | JB4-F Pin 5J, 5K, 6A Test Point 71 | N/A |
| Fidex System Bottle 2 Engines | JB4-B Pin 16, 18, 23, 28 Test Point 94 JB4-B Pin 17, 21, 24, 25 Pin 91 JB4-B Pin 19, 20, 22 Pin 100 JB4-B Pin 26, 27, 29 Pin 97 |
N/A |
| Electronic Flight Instrumentation System Reversion | JB4-F Pin 3A, 3B, 3C Test Point 75 JB4-F Pin 3D, 3E, 3F Test Point 72 |
N/A |
| Electronic Flight Instrumentation System Reversion | JB4-F Pin 3G, 3H, 3K, 3J Test Point 69 JB4-F Pin 4A, 4B, 4C Test Point 66 |
N/A |
| Air Data Computer Signal O/P 2 | JB4-F Pin 4D, 4F, 4J Test Point 49 ARINC Hi JB4-F Pin 4E, 4G, 4H Test Point 52 ARINC Lo |
R-ADC-1 Bus |
| Rudder Pedal Force Position Sensor | JB4-F Pin 2C, 2D, 2E, 2F Test Point 64 | N/A |
| Air Data Computer Signal O/P 1 | JB4-F Pin 7B, 6K, 6H Test Point 55 ARINC Hi JB4-F Pin 7A, 7C, 6J Test Point 58 ARINC Lo |
L-ADC-3 Bus |
| Electronic Flight Instrumentation System Bussing | JB4-F Pin 7K, 8B, 8F, 8D Test Point 50 ARINC Hi JB4-F Pin 8A, 8C, 8E, 8G Test Point 53 ARINC Lo |
L-PFD-3 Bus |
| Hydraulic Power Control Right SOV | JB4-F Pin 1B (Relay K50 X1, A2) Test Point 90 JB4-F Pin 1A, 1D (Relay K50 X2) Test Point 93 JB4-F Pin 1H, 1J (Relay K50 A1) Test Point 99 JB4-F Pin 1G (Relay K50 A3) Test Point 96 JB4-F Pin 1B (Relay K138 X1) Test Point 90 JB4-F Pin 1F (Relay K138 X2, B2) Test Point 95 JB4-F Pin 1E (Relay K138 A1, B1, C3) Test Point 98 JB4-F Pin 1D, 1A (Relay K138 A2) Test Point 93 JB4-F Pin 1C (Relay K138 C2) Test Point 92 |
Relay K50, K138 |
| TAWS Power & Control | JB4-F Pin 6B, 6D, 6F Test Point 56 ARINC Hi JB4-F Pin 6C, 6E, 6F Test Point 59 ARINC Lo |
TAWS-1 Bus |
| Integrated Processing System | JB4-F Pin 7D, 7F, 7H, 8H Test Point 51 ARINC Hi JB4-F Pin 7E, 7G, 7J, 8J Test Point 54 ARINC Lo |
R-GP-4 Bus |
Junction Box 4, Board 5
| System | Test Points: Discrete Black, ARINC Blue | Miscellaneous Equipment |
|---|---|---|
| Auto Pilot System Switching, Master Disconnect, Stall Protection System | JB4-C Pin 4H (Relay K88 X1) Test Point 73 Auto Pilot System Switching JB4-C Pin 2F (Relay K88 X2) Test Point 20 Master Disconnect JB4-C Pin 4D (Relay K88 A1) Test Point 28 Auto Pilot System Switching JB4-C Pin 4E (Relay K88 A2) Test Point 22 Auto Pilot System Switching JB4-C Pin 4F (Relay K88 B1) Test Point 26 Auto Pilot System Switching JB4-C Pin 4G (Relay K88 B2) Test Point 25 Auto Pilot System Switching JB4-C Pin 4J (Relay K88 C2) Test Point 23 Stall Protection System JB4-C Pin 5A (Relay K88 C3) Test Point 16 Stall Protection System JB4-C Pin 4K (Relay K88 D2) Test Point 71 Stall Protection System JB4-C Pin 5B (Relay K88 D3) Test Point 13 Stall Protection System |
Relay K88 |
| Master Disconnect, Horizontal Stab Trim Control, Rudder Trim Control, Aileron Cockpit Control | JB4-C Pin 2D (Relay K90 X1) Test Point 32 Master Disconnect JB4-C Pin 2E (Relay K90 X2) Test Point 40 Master Disconnect JB4-C Pin 5C (Relay K90 A2) Test Point 35 Horizontal Stab Trim Control JB4-C Pin 5E (Relay K90 A3) Test Point 24 Horizontal Stab Trim Control JB4-C Pin 2H, 2G (Relay K90 B1) Test Point 41 Master Disconnect JB4-C Pin 5D (Relay K90 B2) Test Point 38 Horizontal Stab Trim Control JB4-C Pin 5F (Relay K90 B3) Test Point 27 Horizontal Stab Trim Control JB4-C Pin 3F (Relay K90 C3) Test Point 31 Aileron Cockpit Control JB4-C Pin 8F (Relay K90 D2) Test Point 37 Rudder Trim Control JB4-C Pin 8G (Relay K90 D3) Test Point 34 Rudder Trim Control |
Relay K90 |
| Aileron Electrical System, Cockpit Control | JB4-C Pin 3D (Relay K53 X2) Test Point 46 JB4-C Pin 4C (Relay K53 A1) Test Point 36 JB4-C Pin 2J (Relay K53 A2) Test Point 33 JB4-C Pin 3K (Relay K53 A3, D2) Test Point 30 JB4-C Pin 3H (Relay K53 B1) Test Point 45 JB4-C Pin 3A (Relay K53 C2) Test Point 39 JB4-C Pin 3C (Relay K53 C3) Test Point 48 JB4-C Pin 3C (Relay K54 X2) Test Point 48 JB4-C Pin 4B (Relay K54 A1) Test Point 47 JB4-C Pin 2K (Relay K54 A2) Test Point 44 JB4-C Pin 3J (Relay K54 A3, D2) Test Point 43 JB4-C Pin 3B (Relay K54 B2) Test Point 42 JB4-C Pin 3D (Relay K54 B3) Test Point 46 JB4-C Pin 3H (Relay K54 C1) Test Point 45 JB4-C Pin 3J (Relay K54 D2) Test Point 43 |
Relay K53, K54 |
| EICAS DCU Interface | JB4-C Pin 6F, 9K, 10E Test Point 5 ARINC Hi JB4-C Pin 6G, 10A, 10F Test Point 8 ARINC Lo |
A-PSEU-1 |
| AHRS Interface | R-AHC-2 JB4-C Pin 8H, 9B, 9H Test Point 17 ARINC Hi JB4-C Pin 8J, 9C, 9J Test Point 11 ARINC Lo L-AHC-3 JB4-C Pin 8K, 9D, 9F Test Point 14 ARINC Hi JB4-C Pin 9A, 9E, 9G Test Point 9 ARINC Lo |
R-AHC-2, L-AHC-3 Bus |
| Fidex System Power | JB4-B Pin 1, 2, 3, 7 Test Point 3 JB4-B Pin 5, 6, 8, 9 Test Point 2 |
N/A |
| Fidex System Firex Bottle 2 Engines | JB4-B Pin 10, 11, 12 Test Point 6 | N/A |
| EICAS Brt/Dim Master Wiring Caution System | JB4-B Pin 13, 14 Test Point 1 | |
| EICAS Brt/Dim Side & Instrument Panel Interface | JB4-B Pin 4, 13, 14, 15 JB4-C Pin 1A, 1B, 1D, 1C, 2A, 2B, 2C, 1E, 1F, 1H, 1G, 1J, 1K Test Point 1 | N/A |
| General Radio Tuning Displays Right System | JB4-C Pin 6H, 6K, 7B, 7D, 8D Test Point 15 ARINC Hi JB4-C Pin 6J, 7A, 7E, 7C, 8E Test Point 12 ARINC Lo |
RB-RIU-6 |
| Flight Management System | JB4-C Pin 7H, 7K, 8B Test Point 18 ARINC Hi JB4-C Pin 7J, 8A, 8C Test Point 21 ARINC Lo |
R-FMC-6 |
| PMAT Connections between cards | ||
11/13/15
Junction Box Tray
Junction box trays hold the junction boxes in the equipment rack. Junction boxes JB1 and JB3 are installed in the trays attached to the LH equipment rack. Junction boxes JB2 and JB4 are installed in the trays attached to the RH equipment rack. Each junction box tray has two hold-down clamps that lock the junction box into the tray. Each tray has a connector at the rear end. The connector at the rear of the tray supplies the interface from the junction box to the aircraft system wiring.
11/13/15
Junction Box Circuit-Cards
There are four junction boxes that contain five different circuit-cards, for a total of 20 circuit-cards. Each circuit-card contains two circuit-card connectors, a test point connector, relays, diodes, and two lock-tabs (remove/install). The circuit-cards are made to prevent the incorrect installation through a mating pin on each circuit-card. Two circuit-card connectors (50 pin and 92 pin) are found on the front edge of each circuit-card. The function of the circuit-card connectors is to connect the circuit-card to the portable maintenance access-terminal (PMAT) secondary flexible circuit-card.
System Operation
A junction box receives inputs from different aircraft systems through the connector at the rear of the unit. The junction box transmits these systems through the box and it lets system tests to be done. Also, it changes the condition of the relays in the box if the related system supplies data to do it.
The input power to energize the circuit-card relays is 28 VDC. The input power transmitted in each line with 22 AWG pins and 20 AWG pins is as follows:
- The 22 AWG circuits are made to transmit current levels to a maximum level of 3 Amp for each MS22073-3 circuit breaker
- The 20 AWG circuits are made to transmit current levels to a maximum level of 5 Amp for each MS22073-5 circuit breaker.
These levels are a result of time and current. The highest frequency that the junction box receives from an aircraft system is 3200 Hz (for analog signal) and 100 KBPS (for ARINC 429 signal).
A function of the PMAT is to read the RS-422 data bus from the junction boxes through the PMAT connector.
Personnel can get access to all of the ARINC 600 connector pins through a 102-pin test connector located at the front of each circuit-card.
System Test
Junction Box Test Points
There are 5 cards in each Junction Box. Each card has circuits tailored to the operation requirements for that system. There are several types of circuits:
- Pass through circuits, most circuits simply pass through the junction box for monitoring and have no restrictions.
- Jumpered or tied circuits, some circuits need information split to other systems for proper operation, a single circuit coming in may be jumpered to several outputs.
- Relay controlled circuits, the junction box has relays to control various systems throughout the aircraft.
- Other circuits, some circuits require diode protection or resistors added for desired output.
The size and configuration of the boards are different, Rosemont has configured them in the case where the connectors are not aligned the same, a placard on the junction box cover should be referred to for proper plug orientation.
The cards are line replaceable; the flexible harness on the front will require partial or entire removal from other cards to facilitate card replacement.
The flexible card jumpers additional information to the ARINC control card 5 for PMAT information supply. Extension blocks are used to secure sections of the flexible harness and provide test points for the sockets underneath.
Caution:
Components within the Junction Box are ESD sensitive, proper grounding of personnel should be accomplished while working with the test points.
10/15/20
Component Location Index
| Component Location Index | |||
|---|---|---|---|
| IDENT | DESCRIPTION | LOCATION | IPC REF |
| JB1 | JUNCTION BOX | ZONE(S) 221 | 24-63-01 |
| - | JUNCTION BOX JB1 CIRCUIT-CARDS | ZONE(S) 221 | 24-63-01 |
| - | JUNCTION BOX JB1 TRAY | ZONE(S) 221 | 24-63-03 |
| JB2 | JUNCTION BOX | ZONE(S) 222 | 24-63-05 |
| - | JUNCTION BOX JB2 CIRCUIT-CARDS | ZONE(S) 222 | 24-63-05 |
| - | JUNCTION BOX JB2 TRAY | ZONE(S) 222 | 24-63-07 |
| JB3 | JUNCTION BOX | ZONE(S) 221 | 24-63-09 |
| - | JUNCTION BOX JB3 CIRCUIT-CARDS | ZONE(S) 221 | 24-63-09 |
| - | JUNCTION BOX JB3 TRAY | ZONE(S) 221 | 24-63-11 |
| JB4 | JUNCTION BOX | ZONE(S) 222 | 24-63-13 |
| - | JUNCTION BOX JB4 CIRCUIT-CARDS | ZONE(S) 222 | 24-63-13 |
| - | JUNCTION BOX JB4 TRAY | ZONE(S) 222 | 24-63-15 |