SONY KV HA21M50 _ KV HA21M80 _ KV HA21M81 _ KV HA21M80/H _ KV HA21M83 _ KV HA21P52 _ KV HA14M80
Before do any thing, just check the settings first. If sound
MUTE is ON, there will be no sound from the output section. Be sure it
is in OFF state.
The second step is to check whether you get audio signals. To
check this, plug-in a good headphone to the headphone socket. If you do
get sound by headphone, and not from the loudspeaker, make sure that
the headphone socket has some trouble with its internal switchover
contacts. Just push in and take out the headphone pin into the
headphone socket for at least five times, and check you get sound from
the loudspeaker.
If not, check the loud speakers for voice coil trouble. You can
check this without the help of a multimeter. Take a good torch cell,
and connect its two pole with two pieces of wire, and touch these wires
to the terminals of the loud speaker. If the speaker is good, you will
hear a ‘Thumb’ sound for each intermittent touch with wires on the
speakers’ connection tabs. If no sound is heard, be sure that the
speaker I damaged, and should be replaced with same type. Speakers’
impedance will be marked on its magnet.
If the speaker is found good, and there is no sound from it, even
though you get sound output by connecting the headphones to its
headphone socket, make sure that the headphone socket is faulty. To
replace it you have to disconnect it from the circuit, and buy a new one
of same type. It is a semiskilled work indeed.
If you can’t get any sound output from the headphone socket by
connecting a good headphone to it, either the audio output IC do not get
proper voltage, or may be defective.
Audio output IC used with this set is [IC203] [AN 5276]. It is a
dual amplifier type, that is, a single IC is used to amplify both
stereo channel signals. Even one channel amplifier stage inside this IC
is defective; you have to replace the IC.
