| Classic Car Radio Repair Call 928-533-9666 - Morning to Midnight! |
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| Tips on removal, installation, operation and troubleshooting of your Classic Car Radio, 8 Track and Cassette machines |
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| Interference on AM Stations, or poor AM reception As AM by its very design responds to and reproduces changes in volume level (this is called Amplitude Modulation), there will always be certain types of interference we can't do anything about. This especially applies to thunder and lightning storms which produce sudden and repeated noise spikes. AM radio is also sensitive to direction, so you can suffer reduced volume (or even temporary loss of signal) when making a turn. Another common problem is loss of signal when going over a bridge, under a stoplight or street lamp, through a tunnel or even when passing another vehicle. Anything made of metal coming close to your radio can greatly affect your AM reception temporarily. There are, however, a few things you can do to ensure that your AM radio is operating properly inside your car, with as little interference as possible. Check or replace your ignition points and condensor, as the constant sparking produces a radio signal. The condensor is there to absorb the sparks and reduce interference. Install an ignition noise suppressor, available at Radio Shack and most auto parts stores. Check and adjust the AM trimmer capacitor, which is located on the back of many car radios. You do this by tuning to a weak station at the high end of the dial, and adjusting the trimmer for maximum volume. Unplug and reconnect the antenna plug several times, as these contacts develop corrosion over time and will be cleaned somewhat by this process. If your radio produces noise when stopping, accelerating or when the car is moving back and forth after stopping, you might have a marginal connection between body and frame. To test for this, operate the radio with the engine turned off and physically push on the car several times to make it rock. If this action produces noise, you will need to go over, check and tighten your body-to-frame bolts. In extreme cases, you may need to remove the bolts completely and clean the mating parts with sandpaper. One last thing you can do is substitute a known good antenna, or even a piece of wire roughly the same length of your car antenna. Simply strip one end, and insert the bare wire into the antenna jack. You'll want to make sure the other end of the wire does not contact any metal surfaces or voltage sources. If your AM reception improves, you likely have a defective antenna, antenna cable or antenna plug and need to replace it. If none of the above measures improves your AM reception, your radio needs attention. |
| Interference on FM Station, or poor FM reception FM is much less susceptible to interference than AM, as it is differences in frequency that the radio responds to (Frequency Modulation). However, many earlier FM radios utilized the AM oscillator and other AM circuits - so many of the measures to improve AM reception can also optimize your FM performance. FM circuitry tends to be much more complex than AM circuitry and runs at a much higher frequency - which also means that the tuning is more critical. An FM radio that is slightly out of "alignment" will suffer from poor reception, station selectivity, drifting and many other problems. As mentioned above, check and clean your antenna plug first. If this does not improve your FM operation, then your radio probably needs professional service. You might try the other procedures mentioned in the AM section just to make sure, but these will generally not have a pronounced effect on FM performance in most cases. |
| 8 Track tapes not playing properly First, make sure the tapes are in good condition. Almost ALL 8 track tapes will need a new pressure pad and foil splice before they will play satisfactorily in any machine. In fact, the old foil splice will probably (not maybe) break very soon, spilling several feet of tape inside your machine before you notice, as the tape will still appear to be playing just fine. Safely removing the spilled tape often requires the services of a technician. Also, make sure your capstan is nice and clean. The capstan in an 8 track machine is the vertical post just to the right of the playback head, and will pull at the tape, often resulting in tape being sucked into your machine. Clean your head and capstan at least every 5 hours of playing time, as the tape is coated with a graphite-type powder which eventually coats the capstan and prevents the proper needed friction to play. Cleaning an 8 track machine can be tricky; you can sometimes poke a finger into an old T shirt, dip it in alcohol and reach the parts that way. But on most machines, you will need a long swab, the end of a plastic toothbrush, etc. NEVER use any metal objects to clean tape heads, they can permanently ruin them in an instant. NOTE: Tape-eating is never the fault of the machine. Unlike the cassette format, the pressure roller is part of the tape cartridge itself. Clean your capstan often to prevent this problem. If most of your tapes play two songs at once (or you can hear music between songs), your machine needs an alignment job. If only a few of your tapes have this problem, then it is likely the tape itself that has fallen out of alignment. A defective pressure pad on the tape cartridge will also cause this problem, preventing proper head contact. |
| Cassette tapes not playing properly Unfortunately, this is usually a problem with the machine. Even if it just needs to be cleaned, most car cassette machines are very difficult (or impossible) to clean from outside the unit. If your cassette player eats tapes known to be good, then you have a defective clutch or idler. poor high frequency response or muddy sound usually means dirty heads or improper alignment. With very few exceptions, most problems with a cassette or the fault of the machine itself, and it needs professional service. |
| Troubleshooting: |
| Removal: |
| Assume the Position! Except for removing the front panel screws (if any), it will probably be easier on your back to do the work upside down - with your legs dangling over the back of the seats and your head and hands under the dash. Then, the electrical connections and physical obstructions will be right in front of your eyes. A flashlight or other light source is very helpful, and you might as well bring the entire toolbox for easy reach, so you don't have to get up from under the dash any more often than necessary. Your blood will rush to your head and you will be rather uncomfortable, so take an occasional break if needed. Unplug the antenna and any electrical connectors to the unit, then scan the area for items you will need to remove to get the unit out of the dash. It might be the heater ducts, ashtray receptacle, parts of the steering column or a host of other objects. Be patient and work carefully, and you'll eventually be able to remove the unit from the car. If the unit is connected by wires without multi-pin connectors, label each wire in two places, then cut or disconnect the wires between the labels so it will be easy to match them up later. If you run into a problem and can't remove the radio because of some unidentified obstruction, E-mail me and I might be able to help if I know the year, make and model of your car. I would rather help you from here than get under there myself! |
| Installation: |
| Watch grounds and speaker polarity! Installation is simply the reverse of the removal steps you took earlier. Be VERY careful to reconnect your speakers exactly the way they were connected before. The negative terminal on some speakers may be connected to chassis ground, and this wire MUST NOTbe connected to a positive speaker connection on the radio, or you can blow it out. Another important point: Though most older radio speaker outputs share a common ground, this is NOT always the case! Some radios require that all speaker connections be completely isolated from each other AND the car and radio chassis. If this is the case, I will usually tag the radio with this warning. But it is always safest to NEVER ground any speaker connection. If any should be grounded, this will be done automatically inside the unit via the chassis and internal connections. Better safe than sorry - right? |
| If there is ever a doubt about how to connect the wires on your unit, please E-mail me - I am happy to help! |
| Classic Car Radio Repair |
| 4783 Glenrosa Prescott Valley, AZ 86314 |
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