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Staticy Radio


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In my 92 SC400 with the NAG... 12 CD changer the AM side of the radio gets rather staticy. The FM side is fine. I expect problems with AM in stormy weather, but this problem is almost constant Some stations come in good, others that should be ok, are at times almost impossible to listen to. Any ideas


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Here's a TSB I got from Alldata that deals with weak AM reception and static. Performing these steps should cure the problem. Hope it helps you out.


Radio - Static Noise On Weak AM Stations



NOVEMBER 30, 1995

SC 400/300


Rheostat (dimmer switch) and other electrical noise may be heard when listening to weak AM stations on a '92-'94 SC 400/300 with either Nakamichi or Pioneer systems. This noise will change in intensity with different electrical loads (turn signal, headlights, rear defogger and A/C).

Improper grounding of the antenna, antenna cable and/or radio chassis can cause this condition.

Do not exchange the radio. Use the following repair procedure:


1) Play the radio on a strong AM station and slowly move the tip of the antenna mast forward and back approximately 2 inches. If static noise is not heard, go to Step 2. If static noise is heard during antenna movement, replace the antenna mast and go to Step 3.

NOTE :Do not touch the antenna mast with your bare hands. Use a glove or non-metallic object to move the antenna. (If you touch the antenna with your hands, you will change the antenna sensitivity).

2) Remove the antenna mast and inspect the base of the mast for corrosion and damage. Clean with 1500 grit sandpaper.

3) Remove the antenna assembly and inspect the inner fender around the antenna hole for corrosion. Clean with 1500 grit sandpaper.

4) Remove the antenna spacer grommet at the top of the antenna assembly and inspect for corrosion. Clean with 1500 grit sandpaper.

5) Reinstall the antenna assembly. Be sure to install the external antenna nut (escutcheon) first. Then install the nut which holds the assembly to the inner bracket.

6) Check to make sure that the teeth on the antenna spacer grommet make good contact with the inner fender well.

7) Inspect antenna cable connection and clean as necessary. Reconnect the antenna cable, the wire harness and the drain hose.

8) Disconnect the antenna cable from the radio, inspect the cable connection for corrosion and clean as necessary. Firmly reconnect the antenna cable.

9) Disconnect the short antenna cable No. 1 from the antenna cable No. 2, inspect the cable connection for corrosion and clean as necessary. Firmly reconnect the antenna cables.

10) The radio/air conditioner assembly is secured to the dash by (4) 8 mm and (2) 10 mm bolts. Remove the (2) 10 mm bolts and replace with the 10 mm bolt with plastic washer (P/N 90901-19036).

11) Make sure that only the plastic washer of the 10 mm bolt contacts the radio bracket. Insulating this ground point will help prevent the transfer of noise from the combination meter into the radio chassis.


Copyright © 2004 ALLDATA LLC

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Thanks for the info.

Kinda makes sense about the electrical loads. I noticed yesterday that while listening to AM, when I used the Turn Signals I could hear them thru the radio, pulsating static. Will try your suggestions

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