Looking for downloadable Service & Owners Manuals for the Realistic TRC-421 Mobile CB.

SOURCE: Realistic TRC-474 User Manual

Unfortunatly a owner's manual is no longer available for that, but here are some general CB hint's and tips. Hope this helps. TRC-424 4-Watt Solid-State Transceiver (210-1522) Hints and Tips Faxback Doc. # 48947 NOISE Your vehicle or boat can be the cause of much noise interference. Since the receiver section of your transceiver is very sensitive, it can pick up even the smallest noise signal and amplify them. Any noise that you hear in the transceiver is almost totally from external sources. The receiver itself is exceptionally quiet. Steady high noise levels can not be totally eliminated by the internal Automatic Noise Limiter circuit (BLANKER). Noise problems can not be solved internally (in the transceiver); they must be solved at the source of the noise. If you wonder if the noise is from your ignition system, the transceiver or an external source, try this simple test. Turn your ignition switch off and set it to ACC (accessories). This turns off the ignition, but supplies power to the transceiver. Most of the noise will disappear - indicating that the source of the noise is your ignition system. This interfering noise can be generated anywhere in the electrical system of the vehicle or boat. The first step in reducing or eliminating this noise is to locate the source of the noise. IGNITION SYSTEM The most common source of noise is the ignition system. This noise can be identified by the fact that it varies with the speed of the engine. It consists of a series of popping sounds occurring at a regular rate that will vary with the speed of the engine and stop when the ignition is turned off. There are a number of things that can be done to reduce this type of noise: 1. Use only the 'radio suppression type' high voltage ignition wire. Most new cars come already equipped with this type of wire. 2. Inspect the high voltage ignition wire and all connections made with this wire. Old ignition wire may develop leakage, resulting in hash. 3. If the noise still persists, replace the spark plugs with spark plugs that have suppressor resistors builtin. Be sure to use the correct type for your vehicle. Other sources of noise are: generator/alternator, regulator, gauges and static discharge. Most of these types of noise can be effectively reduced or eliminated by using bypass capacitors at the various output voltage points. We suggest that you check your RadioShack store for a wide selection of noise reduction accessories. SERVICE AND MAINTENANCE Your transceiver has been built in accordance with RadioShack's exacting quality control standards. However, it should be treated with reasonable care accorded any electronic equipment. Avoid exposing it to severe shock, dirt or moisture. If you run into problems with the unit, we recommend you check the following: 1. If trouble is experienced with receiving. Check VOLUME On/Off switch setting. Be sure SQUELCH is adjusted properly. Is it over-squelched? Check if the unit is switched to an operating channel. 2. If trouble is experienced with transmitting. Be sure the Microphone is firmly connected to the Microphone jack on the unit. Check if the transmission line is securely connected to ANTenna Coax Connector. Check if the antenna is fully extended for proper operation. Are all transmission line connections secure and free of corrosion? Make sure you are fully depressing the push-to-talk button on Microphone. Check PA push-button setting. It must be in 'out' position. 3. If the transceiver is completely inoperative. Check the power cable and fuse (2A). If these checks don't solve the trouble, do NOT attempt repair or adjustments yourself. The unit should be services only by a qualified radio technician. Whenever possible, return the unit to the store from which it was purchased. 10-CODES Citizen band radio operators have largely adopted the 10-code for standard questions and answers. Its use permits faster communications and better intelligibility in noisy areas. The following table lists some of the more common codes and their meanings. 10-1 Receiving Poorly 10-10 Standing By 10-2 Receiving Well 10-13 Advise Road/Weather Conditions 10-3 Stop Transmitting 10-20 What is your location? 10-4 OK 10-33 Emergency Traffic 10-7 Out of Service 10-36 Correct Time 10-8 In Service 10-41 Switch to Channel 10-9 Repeat 10-99 Cannot Copy You WARNING DO NOT OPEN UP THE TRANSCEIVER TO MAKE ANY INTERNAL ADJUSTMENTS. Any internal adjustments can be made only by (or under the direct supervision of) a person holding an FCC 1st or 2nd Class Radio Operator's License. Internal adjustments and/or modifications can lead to illegal operation as defined by FCC Rules and Regulations, Part 95. Such illegal operation can lead to very serious consequences. To Be Safe And Sure: 1. You should never open up the case of your Transceiver. 2. Never change or replace anything in your Transceiver. (wr 08/04/98) Privacy Policy

SOURCE: Looking for a free download of a REalistic TRC-474

torrent scan

SOURCE: how many amps does a Reakistic CB radio TRC-474

4 amps MAX

SOURCE: operating manual realistic trc 452 cb radio

Check out this link I think it will help. http://support.radioshack.com/support_electronics/15777.htm
Tom

SOURCE: Realistic TRC-490 CB Radio Schematics

The old Sams Photofact CB books (nearly 300 of them) will have this as either this model or a cobra 142GTL which is almost identical to it.