Fixing the horn on a Falcon ute
My father owns a 1978 Ford Falcon utility and I have a question
relating to the vehicle’s horn. The horn must’ve worked at some stage early on
in the vehicle’s life but it now doesn’t work and hasn’t worked for 30 years or
so. I wonder now whether the horn may not have even been connected up from new
or could it be possible for the horn to stop working due to constant use?
My father also drives trucks for a living and he had the horn
in one of his trucks disconnected because it would sound without even being
activated. Is there an easy answer to these questions? (K. C., Wangaratta,
electromechanical devices that have an electromagnet and electrical
contacts. Normally, the con-
tacts are closed and when power is applied to
the horn from the horn switch in the cabin of the truck, the magnet bends a
sheet of steel towards it.
This also causes the contacts in the horn to open and so the
magnet power is released and the steel returns to its normal position. This
restores power to the magnet and the process starts again. The movement of the
steel sheet is what creates the sound.
They can usually be repaired by cleaning and adjusting the
contacts. Sometimes it is the horn switch in the truck cabin that is at fault,
where it does not make contact when pressed or it is too sensitive and sounds
the horn when not required.
If you’re not confident about doing it yourself, the horn and
wiring can be easily fixed by an auto electrician. In any case, replacement
horns are readily available from auto accessory stores.
FM transmitter for drive-in cinema
I am helping a small country shire re-open their drive-in
cinema which is equipped with an old version of your Minimitter made in 1992. It
is hopeless at staying on frequency which is more than compounded now with most
car radios using precise frequency tuning, ie, exactly on the spot.
I am looking at replacing it with your 2002 design and would
like to know if this version is stable enough to be reliably picked up with
modern car radios. We are running an AM transmitter which is spot-on but the AM
end of most car radios leaves a lot to be desired in terms of response – not
that these old Australian-made Raycophone projectors go much past 7kHz in terms
of the top end. But they still spit out a good screen image over a 100m throw
onto an 18m screen and they are still running carbons. (L. M., Darlington,
The December 2002
design is crystal-locked so there should be no drift problem.