![]() ![]() Beneath the external button there is often a standard tactile switch soldered to the circuit board. Push button switches can become unreliable with use. ( Never try this on a valve or other mains powered radio.) This indicates that the audio amplifier is working and the fault is probably in the tuner. If you can identify the audio amplifier as a separate module and can identify the audio input to it, touching this with a finger should produce a hum from the loudspeaker, or touching it with a metal screwdriver while you hold the metal shaft should produce a crackle. If the radio shows no signs of life, check for a power supply problem. Once inside, look for common problems such as broken or shorting wires, signs of burnt or overheating components and bulging electrolytic capacitors. You may have to search for hidden screws underneath a label, rubber foot or speaker grill, and the order of disassembly (and reassembly!) may be critical. Sometimes you may come across a combined radio/cassette/CD player which won't come apart easily. Opening a radio is not always straightforward but is nearly always possible once you find the right screws. (The headphone socket incorporates a switch which mutes the speaker when you plug headphones in. If it works with headphones it could be a problem with the speaker or the headphone socket. If there is no sound a very simple test is to try with headphones (assuming there is a headphone socket). Corroded contacts in the battery compartment is common in most types of battery operated equipment, resulting from dead and leaking batteries being left in the device. ![]() If it needs re-threading around the pulleys you will need to examine it carefully to work out how it's meant to go. Look out for other purely mechanical problems such as the linkages, pulleys and strings which operate the tuning dial on an older radio. You should be able to secure it at one end under a screw securing the base of the aerial. As a temporary measure, replace it with a length of wire (say, 50cm, or similar in length to the original aerial). Close inspection will show whether there is any chance of a repair. Telescopic aerials on FM and DAB radios are relatively easily bent or broken. Later radios use silicon transistors, and increasingly through the 1980's and 90's used integrated circuits for some or all of the internal functions.Īll the above types of radio almost invariably follow the superhet design.ĭigital ( DAB) radios are the latest type, introduced in the late 1990's. Vintage transistor radios date mainly from the 1950's or 60's and use germanium transistors, which are less robust than more modern silicon types. They are often AM only (MW and LW, possibly SW) but post war ones may also receive FM. Individual components are wired together rather than being mounted on a printed circuit board. The oldest radios you might come across use valves. A large smoothing capacitor may retain a dangerous voltage after the radio is switched off. Virtually all vintage valve radios operate at high voltages. Don't plug them in while the case is open unless you (and any bystanders) understand how to manage the risks. ![]() Mains powered radios (except those powered by a separate "wall cube" type adapter) are likely to contain dangerous voltages when plugged in. This is covered in the companion page How radios work, which also explains any abbreviations or technical terms you may not be familiar with in this page. A slightly deeper understanding may allow you to localise some of the less obvious problems. These only require a rudimentary understanding of electrical theory. ![]() Many fixable problems with portable radios are common to many types of electronic gadgets, such as loose or broken connections or signs of overheating. On a digital radio, if the display is blank or if it can't tune any stations, that indicates a fault in the tuner section. Any slight hum or hiss from the speaker will tend to indicate that the audio amplifier is working. If there's no life at all in a portable radio, it's probably a fault in the power supply section, possibly a swollen electrolytic capacitor. ![]()
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