# Delta Tank Horn Repair



## pedalpower17 (Jan 9, 2019)

This Delta tank horn is from a late 40s Schwinn.  All components appear to be in relatively good condition and I've cleaned the contact points.  It doesn't work.  I don't know if the problem lies in the button assembly, the horn itself or both.  Anyone have any experience or suggestions to share?


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## TieDye (Jan 9, 2019)

Have you screwed the horn to the mount while testing it? It needs to be grounded.


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## pedalpower17 (Jan 10, 2019)

TieDye said:


> ave you screwed the horn to the mount while testing it? It needs to be grounded.



Yep, it was tested while fully mounted to the tank.


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## Freqman1 (Jan 10, 2019)

First I would check continuity through the button. If that's good then I sometimes give the horn a good wrap with a screwdriver to see if I can get sound. Also try adjusting the screw on the back. Finally you can use a 9v battery to momentarily 'juice' it to break it loose. In cases where there is evidence of rust I have taken these apart and cleaned them and got them working. V/r Shawn


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## syclesavage (Jan 10, 2019)

Do you have a meter to test the button for a closer when the button is pressed ? Also you can test the horn by disconnecting it form the battery body use 2 D batteries. positive + to the wire of the horn negative - to the body of the horn. see if it works or at least buzzes.


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## TieDye (Jan 10, 2019)

@Freqman1  The tip about juicing it with a 9V battery is a good idea.


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## pedalpower17 (Jan 10, 2019)

Freqman1 said:


> First I would check continuity through the button.



Shawn, you're like the Alexa of the vintage bike world!  Thanks.  I guess testing button continuity means some kind of meter, correct?


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## pedalpower17 (Jan 10, 2019)

syclesavage said:


> Do you have a meter to test the button for a closer when the button is pressed



Syclesavage, I don't.   Some kind of simple current meter sold in any hardware store?


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## TieDye (Jan 10, 2019)

pedalpower17 said:


> Syclesavage, I don't.   Some kind of simple current meter sold in any hardware store?



You can get one from Harbor Freight for $7.00 or so. That'll get the job done.


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## TR6SC (Jan 10, 2019)

https://www.harborfreight.com/7-function-digital-multimeter-63604.html
Like TieDie said, cheap. Home Depot, Lowes also.
Very easy to use. They will tell you if you have juice, AC or DC. Also how much. And!!!! The OHM meter function will tell you if the switch/button is working, or if your wires are broken.
Very very easy to use. YouTube.


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## syclesavage (Jan 10, 2019)

Thanks guys on the meter thing


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## pedalpower17 (Jan 10, 2019)

TieDye said:


> You can get one from Harbor Freight for $7.00 or so. That'll get the job done.



Thanks, Deb.  I'll have one soon...


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## pedalpower17 (Jan 10, 2019)

TR6SC said:


> Like TieDie said, cheap. Home Depot, Lowes also.



Thanks, TR6SC.  A long time ago I worked as a bike mechanic, but never required an electrical diagnostic tool...so it's cool that now I'll get to learn how to use one to repair a 70-year-old bike!


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## mr.cycleplane (Jan 10, 2019)

personally the idea of putting a 9 volt battery to a 'rated 3volt' horn is not a good idea. you run the chance of burning the coil. instead-gently pry the tabs on the horn and open it up. clean the back part of the diaphragm (flat piece that will come off with bezel) and the magnet face on the coil inside. clean it as best you can and re-assemble. this should work-unless someone has burned the coil by putting too much 'juice' to it! these are simple and were assembled in the cheapest way-they were expendable. by playing with the adjustment screw on the back of the horn it creates a vibration which gives the sound. electricity thru the coil pulls like an electro magnet-pulling the diaphragm down. the adjusting screw interrupts this cycle by making the diaphragm relax. this happens multiple times per (second) creating the vibration we hear as sound! same principal is used on the big brother to this horn the delta gangway horns found on the elgin and Schwinn prewar motorbikes.


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## rustystone2112 (Jan 10, 2019)

pedalpower17 said:


> Shawn, you're like the Alexa of the vintage bike world!  Thanks.  I guess testing button continuity means some kind of meter, correct?



No , you can test the button using the light bulb and the D batteries and a piece of wire , make a loop , close the button if the light burns  the button works assuming the bulb is good


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## vincev (Jan 10, 2019)

Somereally good tips !!


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## pedalpower17 (Jan 11, 2019)

With all the great tips flowing in, I'm pretty confident that this Delta, and the 49 Schwinn girl, will be honking again.  Thanks to all who offered their experience!  This site is fantastic!


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## pedalpower17 (Jan 13, 2019)

Step 2.  Thanks to syclsavage's suggestion, I've confirmed that the horn assembly works.  The problem seems to be that the button doesn't send any current to the horn.  As seen in photo below, one of the three little tabs that hold the reddish colored cover to the bottom of the button is broken.  Therefore, the cover is no longer held firmly to the base of the button.  This eliminates the firm base against which the button is pressed.  When pressing the button, the cover separates by a millimeter or two from the metal button base.  I suspect that this may negate the required electrical contact within the button.  Thoughts, suggestions, guidance.....or a new button for sale (13/16" diameter of button base)?


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## Archie Sturmer (Jan 13, 2019)

A flaw with the design was that the batteries when installed would put pressure on the switch, tweaking the contacts away from each other. 
This is because the front battery contact was physically (as well as electrically) attached to the switch, (instead of running an electrical wire).
I have tried to jury-rig an assembly by inserting a small block or wedge of wood (non-conductor) to push parts back into position. 
Sometimes the switch is not at fault, it might even be un-tweaked to work again.


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## syclesavage (Jan 13, 2019)

Multimeters don't lie Fregman1 can contest to that for sure.


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## pedalpower17 (Jan 13, 2019)

syclesavage said:


> Multimeters don't lie Fregman1 can contest to that for sure.



Maybe I'm missing something here, but my thought is that if the batteries are good and the horn works, then the problem lies in the button.  Why do I need a multimeter to prove it?  The question is whether I can repair the button or will need to replace it.


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## Archie Sturmer (Jan 13, 2019)

Another question might be, if the design is flawed, how long would the horn operate correctly with a new or repaired switch, until the same symptoms caused by the same uncorrected problem (of the design) might result in the same outcome.  Consider that lead (metal) and lead-acid batteries are heavy for their relative size; the bumps of riding a bike cause the batteries to stress the weak point of the mechanical design to hold them in place - the front contact and connector to the switch.  Also, an entire replacement Delta part sells for about $50(?).

Sometimes multiple function meters may indicate an unstated level of connectivity with an audible signal (e.g., buzz), so some test procedures specify an quality (amperage) factor, such as enough conductivity to illuminate a bulb to full brightness (think flashlight test).


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## syclesavage (Jan 14, 2019)

Meter tells you what has continuity and what doesn't


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## syclesavage (Jan 14, 2019)

I'm with Archie Sturmer on this one.


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## pedalpower17 (Jan 14, 2019)

Archie Sturmer said:


> Another question might be, if the design is flawed, how long would the horn operate correctly with a new or repaired switch, until the same symptoms caused by the same uncorrected problem (of the design) might result in the same outcome.



Point taken...but this bike won't be ridden much at all.  Actually, it's going to be exhibited in the conference room of my office!   I want the horn to work to add a little audible fun to future meetings.  I'll try to repair the switch and, if unsuccessful, then I'll look for the replacement part.   Thanks for your help.


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