User manual AUDIOVOX MS-407

[. . . ] The center indent position is for balancing the front and rear speaker output. EJECT BUTTON Press this button to stop the tape playback and resume radio operation; at the same time cassette tape will be ejected from the cassette slot. WEATHER BAND CHANNEL INDICATORS These indicators show which channel is selected. Whichever channel is selected the corresponding light will illuminate. [. . . ] (If you cannot find a weak station in this range, tune to any strong station, and adjust tuning slightly off station). Adjust antenna trimmer for maximum output. 6 CARE & MAINTENANCE Cassette Always check that the tape is tightly wound inside the take-up spool on the cassette. Never use cassette player when the vehicle temperature is near or below freezing. SPECIFICATIONS Size: Operating Voltage: Output Power: Output Wiring: 7" (W) x 2" (H) x 6 5/8" (D) 178mm x 50mm x 168mm 12V DC, Negative ground 50 Watts max. Compatible with 4 or 8 speakers (AM) 530 ­ 1710 KHz (FM) 88 ­ 108 MHz (Weather band) Ch 1- 162. 550 MHz Ch 2- 162. 400 MHz Ch 3- 162. 475 KHz (AM) less than 25uV (FM) less than 5uV More than 23 dB 50 ­10000 Hz Less than 0. 3% 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 a cassette cleaning cartridge available whereever stereos are sold. Output Impedance: Tuning range: 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. Sensitivity: FM Stereo Separation: Frequency Response: Wow & Flutter: 7 TROUBLESHOOTING 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 8 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. 9 APPLICATION NOTES 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. 99 10 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. [. . . ] Changes in wire harnessing also has contributed to the decline of application problems. This will greatly reduce the potential for alternator whine. Converters Many RV OEM's incorporate converters as a source of 12VDC when connected to shore power (110-120 VAC). Some models put out a very clean DC supply where others may have a considerable amount of AC ripple under maximum load. This AC ripple is filtered by the coach battery when connected into the circuit, but when the battery is removed or disconnected the amount of AC ripple can create major problems for audio and video products. [. . . ]