The radio does not appear in the list of necessary electrical equipment on board the car and is not even included in the basic configurations of some branded auto manufacturers. However, this is the most popular device that accompanies a car enthusiast throughout the history of the use of the car. That is why the repair of radio tape recorders with their own hands is still a rather relevant topic. Some breakdowns can be fixed by yourself. When the radio does not turn on, DIY repair is the first thing that comes to mind for the car owner. And often even minimal knowledge on this topic helps to solve the problem.
The main causes of breakdowns
There are many reasons for the failure of the radio or just turning off its power. But there are a number of those that are considered basic:
- Despite the fact that there are practically no moving parts in the radio, with the exception of models equipped with a DVD, dust and dirt can cause damage. The finest particles can not only clog the motor drive, but also clog the reading eye, which leads to the fact that the radio tape recorder ceases to recognize the disk. Also, USB connectors can become clogged with dust, which means that the radio cannot be able to read information from media.
- Improper installation of the device can lead to a malfunction in the power system and when the volume is increased, for example, the device simply does not have enough power and it turns off.
- A voltage drop in the car’s electrical network or a short circuit can lead to a blown fuse in the circuit.
- In case of improper use, the device can get physical deformation - a break of buttons, regulators and moving parts and connectors.
Tools for repair
In order to repair the radio tape recorder with your own hands professionally, you need to take care of the purchase of special tools and equipment. First of all, this is a set of screwdrivers with various stings. You may have to deal with not only do-it-yourself JVC radio tape recorders, which are considered top notch, but also other models. You need to understand that different brands use bolts with different grooves - sprockets, hexagons, crosses or a simple slot. You will need the appropriate tool or a universal screwdriver with interchangeable nozzles.
Surely you will need side cutters, pliers, a soldering iron, and preferably two - powerful up to 100 watts and small up to 45 watts.
To determine the break in the electrical circuits and the power rating on the power supplies, you will need a tester - a multimeter. In general, this is all that is needed to repair the Pioneer radio tape recorders with your own hands and other models.
The radio does not turn on or the screen does not light
How to determine if the radio is broken? It could be anything. It does not play, does not turn on, does not see a CD or a USB flash drive, the monitor has gone out, the button has fallen off, and so on. The main failure is the lack of response to the “On” button and the missing screen backlight. The cause of this malfunction is a malfunction of the power supply. He does not give out the required voltage.
To verify this, after providing access to the power supply, you need to measure the voltage at the 2 pins of the CN701 connector. The voltage should be 14 volts on the connector. If this is not the case, then most likely the transistor or zener diode burned out. It must be replaced with the same one, dropping a damaged element from the printed circuit board. Sometimes the signal to turn on the device does not pass due to a power failure on pin 40 of the IZ901 connector.
The sound is gone or there is a rumble
DIY radio repair allows you to restore power to the device. You can also try to eliminate problems such as the lack of sound after turning on or the appearance of a hum in the speakers. First of all, the reason may lie in the absence of a signal of the StandBy system. Typically, 4.8 volts disappear on the IC901 connector at its 4th pin. In this case, it will be necessary to replace the entire controller or clean the contacts on the power amplifier.
If a background appears, amplifying with increasing volume, you need to check the nominal voltage at the bases of the transistors of the amplifier stage. If the device showed "0" based on the transistor, then the trace element will have to be changed. Sometimes the presence of the background is affected by the volume control button itself. This is manifested by the fact that the sound level does not change when you turn the knob in any direction. In this case, it will be necessary to replace the transistor Q802.
Any violation of the sound - the background or the lack of ability to regulate it - this is a malfunction in the amplifier stage. Most often dry containers. It is easy to change the capacitor, you can determine the faulty one directly on the board, although for clarity of measurements it is best to unsolder it from the circuit.
The device does not play files from the disk and USB media
The main reason that the file on the disk or on the USB flash drive does not play is its recording in a different format than the one that the radio tape recorder can read. In this case, you do not need to repair anything, you just need to overwrite the file in the usual format for the radio. Usually the most common is MP3.
If the information is not read only from the CD-ROM, then most likely this is due to contamination of the reading eye with a laser and a photocell. You can restore the work using a special cleaning disk or manually, but you will have to completely disassemble the radio case, since the peephole is in the middle of the device.
In rare cases, the laser power is lost. To fix the problem, it is necessary to measure all the conclusions from the power supply by the tester, checking the results with the nominal value recorded in the circuit.
Sometimes the reason is in the loop connecting the moving part of the laser eye with the rest of the radio circuit. Do-it-yourself repair of the radio cable loop consists in pulling up the bots that hold it on the board.
Buttons on the front panel do not work
Reviews of the repair of Chinese radio tape recorders with their own hands most often reflect precisely mechanical breakdowns, such as the failure of buttons on the front panel or simply their loss from the device. This problem most often occurs with low-quality and cheap models by unknown manufacturers or on obvious fakes. A broken or dropped button will have to be replaced.
If it is in place, but there is no reaction when pressed, you need to restart the system and return the settings to the factory standard. To do this, the radio power supply is completely cut off, that is, all power connectors are disconnected, and after 3-5 minutes everything is connected back. During the shutdown, all microcurrents accumulated in the capacitors will expire, and the processor will return to the factory firmware.
The radio is warming up
You can repair the radio with your own hands if, after a short work, it heats up significantly. Most often, a device with such a problem also turns off on its own. The reason is poor contact between the power cable and the power supply.
To eliminate it, it is enough to check all the contacts and clean them, not forgetting that electronics is the science of contacts.
Heating of the appliance may result from insufficient ventilation. Most often, such a problem is observed in the Pioneer radio. But it manifests itself in the hot season, especially if the device is installed in a car without an air conditioner.
Many masters who fix the breakdowns of Pioneer, JVC, and other original radio tape recorders begin repairs with a hard restart of the system, that is, resetting to factory settings. Often this helps. As experts say: seven troubles - one reset.
No radio signal
If the radio does not work, DIY repair is also possible. The problem manifests itself in such a way that when the radio mode is turned on, only noise and interference are heard.
Most often, the reason is that the antenna just fell off the device. This is easy to check - the antenna connector is located on the back of the radio. It doesn’t matter which antenna is active or passive. To obtain a stable signal within the city, the wire itself is enough.
If, with the antenna turned on, the scanner still cannot tune to any channel, then the cause may be a leaked or dried capacitor in the radio unit. You can identify a damaged item using a tester or even visually. After replacing the element, the radio starts to work.
Conclusion
A modern radio tape recorder is a fairly simple device with a minimum of electronic elements that can break. The processor itself is a microcircuit that very rarely fails. And the fact that around it - capacitors, resistors and fuses - is easy to change by dropping out of the circuit. Well, we must not forget about the quality of contacts. It is unacceptable to use the so-called "twist" wires. You need to connect them only through special connectors. Observing the conditions for proper installation, you can protect the device from breakdowns. You should also be careful about the device during operation. Then he will serve for many years.