User manual AUDIOVOX MS-306

[. . . ] The direction of tape movement is shown by the PROGRAM INDICATORS (7). If the tape is allowed to fast forward or rewind all the way to the end, play will automatically begin from that point. TUNING KNOB Rotate the tuning knob clockwise or counter-clockwise to tune in the station of your choice. Adjust the knob until the station is received with the best possible reception. 7. [. . . ] Compatible with 4 or 8 Speakers (AM) 530 ­ 1710 KHz (FM) 88 ­ 108 MHz (AM) less than 25uV (FM) less than 5uV More than 23 dB 50 ­10000 Hz Less than 0. 3% Output Impedance: Cleaning of Tape Head & Capstan Since tapes contain oxides, you will find a black residue builds up on the head and drive capstan (inside cassette door). These residues should be cleaned after 50-100 hours of accumulated tape operation. You can use cassette cleaning cartridges available where ever stereos are sold. Tuning range: Sensitivity: FM Stereo Separation: Frequency Response: Wow & Flutter: DE-MAGNITIZING The movement of the magnetic tape across the tape head and metal parts causes a magnetic field to develop. We recommend you have the tape player demagnetized at least twice annually. You can purchase an inexpensive tape head demagnetizing tool to do this yourself. AM/FM RADIOS Symptom No Power No 12VDC Cause Possible Solution Check circuit fuse at source Check in-line fuse on power lead (wall mount units are located in rear cabinet) Power lead disconnected Ground connection Circuit fuse at source In-line memory lead fuse Check continuity of speaker leads to ground Check for proper speaker wiring. Note: Radios have a sticker on them explaining wiring color code. Power indicated; No audio output No 12VDC to memory lead (electronically tuned units only) Speaker Output shorted Speaker out cross channeled Only one channel (right or left side) Radio Balance Speaker Disconnected Speaker lead shorted or grounded Speaker wiring shorted or positive lead grounded Speaker terminals grounded or shorted Popping in one or both channels Check radio function Check speaker connection at radio and/or speaker Check speaker wiring continuity to ground w/tester or meter Leads from speaker cone to terminal touching metal basket or speaker No AM Reception Antenna disconnected Antenna mast grounded or shorted Antenna center lead broken Connect antenna Check antenna or substitute with antenna known to be good Check antenna or substitute with antenna known to be good Note: Antenna leads can be tested with continuity or multi-tester. Some may have electronic component (capacitor) built-in which will not allow it to be tested. Audiovox Specialized Applications, LLC TECHNICAL BULLETIN AM/FM RECEPTION Many vans and RV's have more than one AM/FM radio. The best way to insure good reception is to supply a separate antenna for each radio. Other options available to supply adequate AM/FM reception to these radios are listed below, along with some general information in regards to radio reception. AMPLIFIED AM/FM ANTENNA A popular second antenna that can be used is our AB-100 amplified AM/FM antenna. It is small and has a retractable mast that can be mounted vertically or horizontally. This antenna provides good FM reception, but the AM reception will be compromised to some degree because of the length of the mast. "Y" ADAPTERS The "Y" adapters used to connect one antenna to two radios will only provide AM reception to one of the radios and will compromise both AM and FM reception. MAST LENGTH AM/FM antennas compromise AM reception by design. The optimum mast length for FM is approximately 30 inches which is standard for most automotive antennas. The optimum mast length for AM reception is over 100 inches which is not practical for mobile applications. Special circuitry in electronic tuned radios or AM trimmers in mechanically tuned radios, make up for some of this difference in optimum mast length for AM reception. FM RECEPTION FM reception can be received with a very limited antenna and strong local FM stations can be received without an antenna, depending on the circumstances. ANTENNA CABLE CONCLUSION Increasing the antenna lead cable (adding extensions) will reduce sensitivity of AM with electronic tuned radios. AM/FM reception is subject to the choice of an antenna and it's application. There can also be a variety of methods used to supply signal to both primary and secondary radios, but AM performance is the ultimate "test". It appears that consumers or end users are becoming much more critical when it comes to acceptable antenna performance. It may be necessary for manufacturers to re-evaluate what was once considered acceptable. GROUND PLANES Ground planes are also important when considering antenna performance. Most automotive antennas are designed to be mounted on the metal body of the vehicle. [. . . ] The voltage at the VCP can be another . 5VDC (11 VDC) less than the TV. Ignition Systems In conclusion, operating these video products without the engine running will drain the battery to the point where these products will perform unacceptably in a short period of time. Unwanted noise generated from the ignition systems used to be a big problem. However, with more sophisticated filtering circuits designed into audio/video products, these problems are not as wide spread. Changes in wire harnessing also has contributed to the decline of application problems. [. . . ]