TRIMMER ADJUSTMENT

1. Remove the right hand knob, trimmer screw is accessible through the hole in the control panel.
2. With antenna fully extended, turn the radio on.
3. Tune the radio to a weak station between 600 kc and 1000 kc. Adjust trimmer screw until the best reception is obtained for that station.
4. If a shunt wire was used, remove the shunt and replace the knob.

 CHECKING ANTENNA (Manual or Power)

To check antenna for partial short, remove lead-in from rear of radio and check resistance from lead-in connector to a good ground using an ohmmeter. Resistance should be three megohmes or more.

Removal-Manual

To remove the antenna mast, loosen the antenna cap nut and lift the mast out of the socket. To remove the lead-in assembly, proceed as follows:

1. Remove windshield wiper arms.
2. Remove vent grille and screen.
3. Disconnect lead-in from radio and pull the cable through the hole in the plenum chamber.
4. Remove lead-in nut, upper spacer and gasket. (Fig. 12-129)
5. Remove the lead-in bracket attaching screw and washer.
6. Remove lead-in assembly and lower spacer by reaching through the plenum chamber.

When installing, be sure to align the lower spacer to the lead-in as illustrated in Fig. 12-129.

Removal-Power

Power antennas are installed as illustrated in Figs. 12-130 and 12-131. The lead-in cable is routed in the body channel and behind the dash insulator.

The following parts of the power antenna are serviceable: Drive Assembly, Mast Assembly and Support Tube Assembly. To service any of these parts, proceed as follows:

1. Remove the two connector- to- support tube screws and remove connector.
2. Unsolder hook-up wire at pin and remove pin and insulator assembly.
3. Remove the three support tube - to - drive assembly screws.
4. While applying a back and forth rotary motion, pull until support tube is removed from antenna.
5. If the drive assembly or mast assembly is to be replaced, proceed as follows:
   1. While applying a rocking motion, pull on mast until insulator bushing is removed from the drive assembly tubular fitting.
   2. Energize motor until entire length of nylon cord is expelled from drive assembly. To prevent a kink or bend in nylon cord, keep it taut by pulling on mast.
   3. If motor is inoperative, it will be necessary to manually remove the nylon cord from the drive assembly as follows:
      1. Place the assembly in a vise so that the normal plane of the nylon cord is parallel with the floor.
      2. Pull on nylon cord until it is completely expelled from the drive assembly.

Assembly - power

1. Thread nylon cord through bottom insulator, (small diameter end down) and water seal washer.
2. Energize motor and feed nylon cord into drive assembly. Do not allow nylon cord to bend or kink.
3. Push mast assembly into tubular fitting, making sure that the upper edge of the insulator bushing is below the center of the three support rube-to-drive assembly screw holes.
4. Install support tube over mast assembly, making sure hook-up wire is extended through proper hole in support tube. Line up three holes in support tube and install the three screws.
5. Solder hook - up wire to pin and insulator assembly being careful not to overheat.
6. Install connector over pin and insulator assembly and install two screws.

Diagnosis

If antenna fails to operate properly, check the following possible sources of trouble:

1. Excessive tightening of cap nut an quarter panel will result in excessive operating noise in the car.
2. See that ground wire is tight.
3. To determine whether fault is in the antenna or the control circuit, disconnect the leads coming from antenna. Connect a jumper wire from a known hot source and touch jumper wire to each of the terminals of the wires coming from the drive assembly. If antenna does not operate, the fault is in the antenna drive assembly. If antenna does operate, the fault is in the control circuit.
4. If trouble is in the control circuit:
   1. Examine electrical connections at switch, making sure they are securely connected.
   2. Check wiring at switch with lamp or motor.

If antenna lead-in is suspected of being bad, check radio operation using an antenna lead-in known to be good.