Franzis UKW 65287, Руководство пользователя

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Troubleshooting
While assembling the radio, you might make a mistake that is
not so easy to spot. If this happens, do not give up but accept
the challenge! When the radio doesn’t work, you should first
check all connections. Compare your setup with the diagrams
and photos wire by wire. Make sure that all wires are firmly
attached. The most common problems are:
• A wire is attached at the wrong position.
• The end of a wire is too short and does not reach the con -
tact point inside the breadboard.
• A pin of the amplifier IC is bent and not properly connect -
ed.
• Deformation or contamination causes connection problems
at the battery clip or the switch.
• The battery is exhausted and does not provide sufficient
current.
Make sure that a clicking noise is audible when you turn on
the radio. As the volume control knob itself produces a noise,
it may be sensible to keep the radio switched on, remove the
battery and then touch the battery with the clip. When you
don’t hear the clicking, you have to concentrate your trouble -
shooting efforts on connection problems in the area of the
battery, the amplifier and the loudspeaker.
Find out if the amplifier or the voltage regulator heats up, as
this would point to an improper connection. Jiggle the indi -
vidual wires to track down connection problems. Scratching
sounds that appear while you lightly touch a wire or a compo -
nent are caused by improper contacts.
On the other hand, when the loudspeaker does not emit any
sounds, the usual suspects are the loudspeaker itself, the
amplifier and the volume control. Repeat the initial amplifier
test or try the following tests:
• Touch both terminals of the disc capacitor with a wire or a
screwdriver. This should result in a clicking noise with a vol -
ume depending on the setting of the volume control. In this
case, the part of the circuit from the volume potentiometer
to the loudspeaker works correctly.
• If in doubt, remove the disc capacitor and touch pin 2 of
the amplifier with a wire. You should hear a low clicking or
humming sound.
If the radio does not emit any sound although the amplifier
has passed the test, check the FM board, the voltage regu-
lator and the tuning potentiometer. The following problems
may be present:
• The board is not supplied with the required 3 V operating
voltage because the voltage regulator or the negative con -
nection is attached improperly.
• The tuning voltage is always either 0 V or 3 V because the
potentiometer or one of the associated resistors is connect -
ed in the wrong way.
• The NF output is not properly connected to the volume
potentiometer.
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