Horn Problem

I

iain

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8 Oct 2001
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Does anyone have any suggestions as to what might be wrong with the electric horn on my Starfish 8. I'ts one of those stainless steel trumpet shaped ones, I don't know the make I'm afraid. It worked fine before but now when you press the button there is just a brief click but no toot. I've had it apart and although a bit rusty in places, all the important innards seem OK. It would help if I knew the theory how the blooming thing worked, but as I don't I wondered if anyone out there would be able to help. All suggestions welcome. Cheers

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It seems to be my day for replying to posts about horns. The general principal for electrical horns is that when the button is pressed it charges an electromagnet which is connected to a diaphragm , as soon as the diaphragm is pulled in the connection is broken and it pops out again.You should find some contacts that control this. This cycle repeats rapidly and makes the noise which is amplified by the trumpet. The click you hear is the electromagnet working. Somewhere on the body of the horn is probably a locknut with a screw inside it this controls the amount of defllection of the disaphragm & points and can often be adjusted slightly to get the horn working again, --its a fiddly job but persevere after making sure everything is rust free.Dont keep the button pressed for too long before the horn is working to make sure you avoid burning out the windings.

I hope this is of some help.
Cheers

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There is normally a circular diaphram made from springy steel inside. An electro magnet is powered up and that pulls thee diaphram which breaks a circuit to the electro magnet. Magnet releases diaphram which springs back making contact which energises electro magent etc etc. All the above is typicaly at 400 times a second. Normally the contacts have an adjustment screw which you turn in & out till you get the best sound. Aside from an open or shorted coil (electromagnet) the other issues are normally dirty contacts. They take a fair bit of current so make sure the connections are good and clean.

<hr width=100% size=1>Jim

Draco 2500
 
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