Navico-Northstar 2kW JRC Radar Package, Scanner Cable Removal and Replacement This work instruction describes the methods and means for which to remove and reinstall optional scanner cable configurations for the Northstar JRC series 2kW Radar domes. This instruction may also be used as a guide for the replacement of damaged or defective cables. Standard Inventory Configurations P/N NS004790R - supplied with a 15 Meter Scanner Cable P/N NS003100 pre-installed from the factory. P/N NS004790M - supplied with a pigtail cable P/N NS003109 only. The appropriate cable OEM extension cables configuration can be added depending upon installation requirements. P/N NS004790 - "Bare" dome with no pigtail or cabling supplied. Section 1 - Removing a new unit from the packaging With the radar carton facing upright, use a razor knife to carefully open the box along the tape seams on top centerline and ends of the container. Follow the seam lines exactly and DO NOT CUT TOO DEEPLY to avoid damage to the enclosed templates and packing materials. Remove the top cardboard layer. This has the template and installation guide attached to it. Save this for re-use when repackaging the unit. Remove the formed foam packing that surrounds the top of the radar dome. Save this for re-use when repackaging the unit. Inspect the carton to make sure that the bolt package and rubber mounts are included. DO NOT REMOVE THESE PARTS FROM THE CARTON unless the radar is immediately going to be installed on a vessel. Leave these parts in the carton so that they won't be misplaced or forgotten when the unit is re-packaged. Bolt and rubber mount packages Remove the cardboard end packing that retains the radar scanner cable in place if it's installed. When unpacking a unit not having a factory installed scanner cable this will be at the aft end of the unit (the end with the cable gland nut). Note the orientation of the cardboard packing spacer that retains the cable. Save this spacer for re-use when re-packaging the unit. Move the radar and cable assembly to a work station with a padded work surface to begin the disassembly process.
Section 2 - Disassembling the radar to Replace or Reconfigure the scanner cable. Turn the dome top side down on a soft protected work surface and carefully remove the protective plastic bag enclosing the radar dome. Save this for re-use when repackaging the unit. Fully loosen the 4 cover retaining screws using a straight slot screwdriver or 5/16" nutdriver. The screws are captive to the assembly, they should not be removed from the bottom assembly. Grasp the sides of the dome so that the top and bottom halves stay together and flip the dome over so that the dome cover can then be removed. Bottom View of 2kW Dome showing cover screw locations
Remove the six screws that secure the transmitter and antenna assembly to the dome base. There are two #2 Phillips screws and four #1 Phillips screws. Top View with Dome cover removed showing the locations for the screws that secure the transmitter and antenna assembly
Interior view of cable gland nut assembly. Note location of black tape on the cable, the cable is not pulled tight nor is the black tape inside of the gland nut area. Loosen the gland nut and slide the rubber packing out of the gland housing. View of gland nut and packing partially disassembled
Disassemble the packing assembly by sliding the "plastic finger grip" back onto the cable toward the gland nut so that the two rubber wraps can be disassembled and removed from the cable. At this point the cable can be easily moved in or out of the dome housing as required for completing the disassembly. Refer to the two preceding and the following pictures for additional clarity. Individual gland nut components when completely removed from the scanner cable Once removed place the two rubber seal halves aside, they will be needed in the reassembly process.
Lift up the transmitter and antenna assembly and temporarily position the assembly in the "holding clips" built into the forward bottom portion of the radar transmitter mounting base assembly. Transmitter assembly supported by the "holding" clips built into the mounting base Position and routing of the scanner cable along with the orientation of the cable clamp used to secure the scanner cable to the transmitter assembly
Work the cable back through the cable gland to obtain extra slack in the cable. If possible reposition the transmitter and antenna assembly into a padded jig allowing the assembly to be positioned with the shield and transmitter face up. This will allow ease of access to the shield and cabling components. Make sure that the antenna and the plastic gearing will not be damaged by contact with any portion of the jig. If a jig is not available, position the assembly in the holding clips located in the base assembly. Work carefully to avoid any damage to the transmitter and antenna components. View of the transmitter shield cover showing the locations of the shield screws. Remove the transmitter shield screws, black in color, eight each, using a #1 Phillips screwdriver. Caution - do not remove the two screws securing the power transistors that are heatsinked to the aluminum baseplate assembly. These are located next to the shield screws at the end of the shield that is opposite where the scanner cable enters the shield. Once the shield cover is removed, remove the screw that secures the scanner cable clamp and the grounding strap to the transmitter housing. The scanner cable is stiff and will attempt to "spring back". Do not allow the cable to apply tension or stress to the data wires, connectors or the PCB assembly. Firmly hold the cable when the clamp is removed and use slack in the cable to reposition the cable and remove the tension.
View showing the cable clamp screw and shield grounding connection with the transmitter shield removed Disconnect the seven pin data connector by carefully grasping the connector body and pulling straight up. The connector is a snap fit without a locking device. Do not rock the connector from side to side when removing it to avoid bending pins or pulling individual wires loose. Disconnect the three pin power connector by depressing the locking tab and pulling straight up on the connector. Picture showing both connectors removed. The three pin connector has a latch; the seven pin connector is a press and snap fit.
Once disconnected the scanner cable can be removed from the lower half of the dome. Carefully thread the connector bodies and shield strap back through the cable gland housing. Due to the amount of clearance in the gland housing this will normally need to be done one connector at a time. Remove the "plastic finger grip" and the gland nut from the cable. Place these with the two rubber seals removed earlier. All of these parts will be re-installed when a new cable is installed. Helpful tips - To save time and to prevent difficulties during assembly, pay close attention to the following areas 1.Place the cable gland nut and "plastic finger grip" on the new cable before you start assembly. 2. Verify that the power and data connectors are correctly and firmly seated both by feel and with a visual inspection. 3. Verify that none of wires are pinched or can be chafed by edges of the shield or any internal metal parts. Cable and wire routings are very specific, DO NOT make changes. 4. Verify correct orientation of the cable clamp. The shield will not seat correctly if the clamp is orientated incorrectly. 5. Verify that the connection of the bonding strap and that it is correctly installed beneith the scanner cable clamp. 6. Verify that the transmitter shield is correctly placed and fitted. There are two metal guides located on the transmitter base plate. When properly placed, the shield goes over and to the outside of the guides. If the shield mounting holes don't line up this is the common cause. 7. Verify correct routing of the scanner cable in the dome bottom during final assembly.
Reassembly Possible scanner cable length configurations. If assembling a BBG 1.125M pigtail cable configuration, use Northstar P/N NS003109 If assembling an Aftermarket 15M cable configuration, use Northstar P/N NS003100 If assembling an Aftermarket 20M cable configuration, use Northstar P/N NS003101 Install the gland nut and "plastic finger" grip on the new scanner cable to be installed. The gland nut is installed on the cable first with the threaded portion facing toward the scanner end of the cable followed by the "plastic finger grip". These must be installed onto cable before routing through the gland housing and into the radar dome bottom. The rubber seal halves are not installed at this time but will be installed during the final assembly. Route enough cable through the cable gland to allow some slack for orientating the cable. Using the preceding pictures in the disassembly instructions as a guide, route the scanner cable into position so that the connectors can be inserted into there respective locations on the transmitter board without undue twisting or straining of the wires or PCB connections. If necessary, firmly grip the cable and bend it as required to properly position the wires. The "proper" bend will allow the correct positioning of the cable clamp to restrain the scanner cable without putting undue strain on the connections. Loosely assemble the scanner cable clamp and clamp screw allowing enough space under the clamp to insert the spade terminal attached to the shield ground. Position the cable and align it so that it will exit the transmitter board as shown in the preceding pictures. Correctly position and hold the shield ground and scanner cable while tightening the clamp screw. DO NOT OVER TIGHTEN. The clamp screw threads into the aluminum sheet metal base and it's threads can be stripped if over-tightened. The cable will exit at 90 degrees to the long axis of the transmitter board when correctly positioned. Install the transmitter shield cover making sure none of it's edges are touching the scanner cable or the wire bundle for the servo motor. Fit the covers touches the motor wires refit them so that they are pushed into the slot between the motor housing and the PCB is that the shield can not come in contact with them. Secure all eight shield cover screws. Inspect all hardware and wires for security and proper placement. Lift up the transmitter and antenna (T/A) assembly and adjust the scanner cable until the assembly can be lower down onto it's normal mounting location. Loosely install the six screws that secure the T/A assembly to the bottom mounting plate. Verify the correct positioning of the scanner cable and then tighten down the six T/A mounting screws Adjust the scanner cable so that it does not rub or chafe on any of the interior parts.
Assemble the packing assembly using the preceding pictures as a guide. Note that the large portion of the taper on the smaller inner seal is orientated away from the radar while the large portion of the taper larger outter seal is toward the radar cable gland housing. Align the seals so that the splits are 180 degrees apart. Work the "plastic finger grip" up over the end of the seal assembly that is away from the gland housing. (The "small" end) Line the seal up inside the gland housing and carefully thread the gland nut on using care not to cross the threads. Once the threads are correctly started, tighten up the assembly hand tight. DO NOT USE PLIERS or gripping tools on the plastic gland nut to avoid damage. When properly assembled this assembly only requires tightening by hand in order to be waterproof.