 Old Horns |
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| zoomCat |
 Aug 13 2020, 03:02 PM
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#1
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Member  Group: Members Posts: 161 Joined: 13-August 04 From: Cincinnati, OH Member No.: 2,526 Region Association: None 
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I've got some original Hella horns, original equipment on the car, but they've been silent for 30 odd years. Putting 12 volts across the lugs doesn't do anything.
Modern replacements look all shiny and new, even though it's something nobody else will likely ever see I thought I'd try to bring the originals back to life.  Opening them up they actually look pretty good.   I don't see any broken wires, and the corrosion is minimal. The sprung contact points on the right don't seem to be connected in a way that would allow the thing to move in response to the magnet. Anybody know what I'm looking at here? Any particular diagnostics I can do? |
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| Superhawk996 |
Aug 13 2020, 03:50 PM
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#2
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914 Guru Group: Members Posts: 5,784 Joined: 25-August 18 From: Woods of N. Idaho Member No.: 22,428 Region Association: Galt's Gulch
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Note: I've never played with one of these - hopefully others with direct experience will chime in.
Operational principle is of a simple electromagnet. Contacts are a make/break affair in response to the diaphram moving. Check coil continuity with DMM. I would suspect contacts should be starting from a closed condition. |
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| dr914@autoatlanta.com |
Aug 13 2020, 04:06 PM
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#3
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914 Guru Group: Members Posts: 7,841 Joined: 3-January 07 From: atlanta georgia Member No.: 7,418 Region Association: None |
our man carson (ex navy seal) restores these horns here at our shop and gets the vast majority to work again is usually the points.
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| 914werke |
Aug 13 2020, 04:28 PM
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#4
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"I got blisters on me fingers" Group: Members Posts: 10,052 Joined: 22-March 03 From: USofA Member No.: 453 Region Association: Pacific Northwest
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Ive done a fair # of them your example is a very early version since it has actual screws later ones used rivets.
Because of their location ...corrosion!! |
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| Retroracer |
Aug 13 2020, 07:50 PM
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#5
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Senior Member Group: Members Posts: 610 Joined: 7-July 13 From: Bend OR Member No.: 16,100 Region Association: Pacific Northwest
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I kept mine (both broken), put aside to tinker with at some later point. So tracking this thread with interest.
Anyone know what the original "factory-fresh" finish would have looked like? - Tony |
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| bkrantz |
Aug 13 2020, 08:06 PM
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#6
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914 Guru Group: Members Posts: 7,754 Joined: 3-August 19 From: SW Colorado Member No.: 23,343 Region Association: Rocky Mountains
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When you give it 12 volts, does anything move, even once?
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| bbrock |
Aug 13 2020, 10:01 PM
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#7
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914 Guru Group: Members Posts: 5,269 Joined: 17-February 17 From: Montana Member No.: 20,845 Region Association: Rocky Mountains
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What are you using for a power source? I haven't messed with my original horn, but when I hooked up my brand new Hella Sharptones to a 12v, 3 amp power supply, I got nothing. When I hooked them to a charged car battery, they about broke my eardrums. I just needed more current to get them moving. Not sure if that applies to the old horns.
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| zoomCat |
Aug 14 2020, 12:16 AM
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#8
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Member Group: Members Posts: 161 Joined: 13-August 04 From: Cincinnati, OH Member No.: 2,526 Region Association: None
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QUOTE(bbrock @ Aug 14 2020, 12:01 AM)  What are you using for a power source? I haven't messed with my original horn, but when I hooked up my brand new Hella Sharptones to a 12v, 3 amp power supply, I got nothing. When I hooked them to a charged car battery, they about broke my eardrums. I just needed more current to get them moving. Not sure if that applies to the old horns. I’m using a 10 amp battery charger. I get nothing when it’s connected. |
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| Superhawk996 |
Aug 14 2020, 06:01 AM
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#9
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914 Guru Group: Members Posts: 5,784 Joined: 25-August 18 From: Woods of N. Idaho Member No.: 22,428 Region Association: Galt's Gulch
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QUOTE(zoomCat @ Aug 14 2020, 02:16 AM) I’m using a 10 amp battery charger. I get nothing when it’s connected. Try a battery per @bbrock suggestion. Some battery chargers aren't true DC voltage output. There are some battery chargers that are simply half wave rectifiers and may not drive the electromagnet properly which is looking for a solid 12v DC.  https://lastminuteengineers.com/the-half-wave-rectifier/ |
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| 914werke |
Aug 14 2020, 01:46 PM
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#10
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"I got blisters on me fingers" Group: Members Posts: 10,052 Joined: 22-March 03 From: USofA Member No.: 453 Region Association: Pacific Northwest
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(IMG:style_emoticons/default/agree.gif) Use a car battery. Remove the potting from the adjustment screw and after its all cleaned & reassembled adjust to the correct tone...Just wear ear protection (IMG:style_emoticons/default/happy11.gif)
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| CHIZ 914 |
Aug 14 2020, 11:09 PM
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#11
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Member Group: Members Posts: 200 Joined: 14-May 18 From: Mountlake Terrace, Wa Member No.: 22,118 Region Association: None
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Rich knows! My horns work and look factory new! THX
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