Spartan horn assembly pictures

1941 - 1945, MB, GPW Technical questions and discussions, regarding anything related to the WWII jeep.
RMarchi
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Spartan horn assembly pictures

Post by RMarchi » Mon Sep 24, 2018 8:01 am

I had a short in my Sparton horn. I determined the screws holding the
Internal electrical components were the issue. I also realized those components were not assembled correctly. I'm not sure if a insulator is missing. At some point it was disassembled...

So, after hours of searching the internet. Does anyone have pictures showing clearly the correct assembly order of the internal electrical components.


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Re: Spartan horn assembly pictures

Post by YLG80 » Mon Sep 24, 2018 8:42 am

Have a look at the miljeep link provided in my earlier post here :
viewtopic.php?f=4&t=299883&p=1740675&hi ... n#p1740650

Yves
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Re: Spartan horn assembly pictures

Post by RMarchi » Mon Sep 24, 2018 5:16 pm

Thank's.

I've seen these pics. What they dont show is clearly where for example the insulator wafers go or the one small plate connected to the coil.

I have had so much trouble with this horn i was hoping to find a simple picture laying it all out clearly. However, at this point i do not think one exist anywhere.

Thank you again for your help!

Rob

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Re: Spartan horn assembly pictures

Post by YLG80 » Thu Sep 27, 2018 4:42 am

You have likely a problem with the insulators in the switch vibrator assembly
The following Sparton assembly drawing is not from the same R2-14 Sparton horn, but it's similar.
It shows that the screws holding the stack of contacts and insulators does not have to touch the contacts
Horn_stack_contacts-vibrator.jpg
Horn_stack_contacts-vibrator.jpg (31 KiB) Viewed 995 times
Here are other detailed pictures of the electromagnetic part of the assembly:
viewtopic.php?t=207809
other details
viewtopic.php?t=98646

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Re: Spartan horn assembly pictures

Post by RMarchi » Tue Oct 02, 2018 9:35 pm

So, I finally eliminated the short in the horn based upon the volt meter - along with any sound coming from the horn - UGH!!!

I drew a picture of how I assembled the horn. If anyone can "Please" take a look and tell me if I did it correctly or not. If not please correct the drawing.

Thank you

Rob
Sparton Horn Diagram.jpg
Sparton Horn Diagram.jpg (69.04 KiB) Viewed 937 times

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Re: Spartan horn assembly pictures

Post by YLG80 » Wed Oct 03, 2018 3:56 am

Nice drawing !
I believe that the lower contact #1 with the soldered wire is not at the right place.
It should be like this:
Sparton_R2-14_contacts-stack.jpg
Sparton_R2-14_contacts-stack.jpg (49.01 KiB) Viewed 924 times
The plate with the wire shown in the rectangle has to be in contact with the plate pointed by <- metal on your drawing.

The metal bracket with two holes and a soldered black wire has to make contact with the lower contact point but be insulated from the ground/casing.

The other black wire with the single round terminal has to make contact with the top contact point.
Sparton_contacts.jpg
Sparton_contacts.jpg (73.7 KiB) Viewed 924 times
Neither wires can be allowed to be in contact with the ground.
The insulated rectangular pieces and the 2 insulated sleeves are there for that reason.

When you will have no points shorted to the ground and a good contact between the points and the black wires, you should hear at least a click when you power the horn.
After that, you will have to slowly adjust the screw to hear the "hunk hunk" :)

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Re: Spartan horn assembly pictures

Post by RMarchi » Fri Oct 05, 2018 6:26 pm

Well...I made the change as you suggested and I got clicks! I even started to get tones after moving the adjusting screw. I connected it to the correct wires and pressed the horn button and to my surprise the horn responded.

Now the bad news. After 3-4 horn button trys the horn stopped working.

Any suggestions...

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Re: Spartan horn assembly pictures

Post by YLG80 » Sat Oct 06, 2018 12:47 am

RMarchi wrote:
Fri Oct 05, 2018 6:26 pm
Well...I made the change as you suggested and I got clicks! I even started to get tones after moving the adjusting screw. I connected it to the correct wires and pressed the horn button and to my surprise the horn responded.

Now the bad news. After 3-4 horn button trys the horn stopped working.

Any suggestions...
This is good news !
That means that your stack of contacts and insulators is OK.
Be sure that everything is clean (see picture below) especially the contact points
Sparton_horn_R2-14_MB-GPW.jpg
Sparton_horn_R2-14_MB-GPW.jpg (80.7 KiB) Viewed 861 times
At rest, the contact points should be electrically closed, measured with an ohmmeter.
Clean the contact with emery cloth, fine grain) and polish the contacts (Dremel with wire brush).
Check that the contacts are aligned, after reassembly.
Return the screw at the position where it gave clicks, original position.
Readjust again. It's really sensitive.
Yves
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Re: Spartan horn assembly pictures

Post by RMarchi » Sat Oct 06, 2018 4:04 pm

Yves,

I did as you suggested, though there was little to no rust on the contacts.

I have a question on the diaphragm and specifically the nipple (see picture). How does it fit together with the coil/electrical component housing (see picture).

Th
#1.jpg
#1.jpg (55.64 KiB) Viewed 825 times
#2.jpg
#2.jpg (74.58 KiB) Viewed 825 times
ank you again for all your help!

Rob

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Re: Spartan horn assembly pictures

Post by YLG80 » Sun Oct 07, 2018 1:50 am

Yes your horn looks very clean !
The little nipple has to push on the phenolic lever as shown below.
Horn_diaphragm_tongue_position.jpg
Horn_diaphragm_tongue_position.jpg (78.94 KiB) Viewed 803 times
This is what's opening the contacts when the magnetic circuit enters in vibration.

On the next photo you can see the trace of that nipple on the lever.
Sparton_diaphragm_nipple_position.jpg
Sparton_diaphragm_nipple_position.jpg (42.81 KiB) Viewed 803 times
Don't give up, that adjustment is critical and that's the reason why Sparks-Withington Co has taken patents on how to make the assembly and adjustment :) :)!
Yves
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Re: Spartan horn assembly pictures

Post by RMarchi » Mon Oct 08, 2018 11:40 am

Yves

No joy...

I only got a very week toot. I now suspect it is in the horn button wiring? Do you agree?

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Re: Spartan horn assembly pictures

Post by YLG80 » Mon Oct 08, 2018 12:30 pm

Yes it's possible.
When you switch the horn ON via the button, there is a strong spark between the button contacts.
It gradually destroys the contacts, increasing the ON resistance.
If it's the case, the horn has not ehough current to work normally.

That's the reason why it's always better to add a diode accross the horn contacts.
The diode will clip the over-voltage.
Sparks Withington took also a patent on a horn with a diode after WW1.

It's easy to verify.
Try to connect the horn directly to the battery.
Yves
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Re: Spartan horn assembly pictures

Post by Chuck Lutz » Mon Oct 08, 2018 1:13 pm

1) is the battery fully charged?
2) the horn will sound the loudest and best with the engine running
3) adjust the horn with the engine running

It does not go "Beep-Beep"....more like "Meep-Meep" when working properly.
Chuck Lutz

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Re: Spartan horn assembly pictures

Post by RMarchi » Mon Oct 08, 2018 4:22 pm

The battery is fully charged and I also tried with the engine running, but that didn't help.

Regarding the diode. Where do you get one? Auto store and is there a particular size.

So, I guess I'll call Ron and order another Horn wiring kit (it's like my 3rd + by now)

Thanks again!

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Re: Spartan horn assembly pictures

Post by YLG80 » Tue Oct 09, 2018 1:44 am

You shouldn't give up.
Your horn was producing a sound so it should work.

You should not debug the horn by connecting it in the jeep wiring.
Doing that, you insert 4 unknown status devices in the circuit : the horn, the wiring, the wheel button and the steering column ring contact.
The ring contact in the steering column is often the cause of false contacts and squeaking noise.

You should put a mat on the passenger side fender and test-adjust the horn only on it.
You should make a direct connection with the battery by means of 2 wires.
When the horn is OK, then you will connect it in the jeep wiring.

Regarding the diode, it's is to be found in an electronic shop.
Each time a coil is switched in a DC circuit, the voltage overshot should be reduced by means of a diode.
This is good for a relay or for a horn.
If there is no diode in the horn, try to put your finger on the (+) terminal and activate the horn.
Tell me how you feel afterwards :D !
In a car circuit, the overshot is somewhat clipped by the high capacity in the circuit (condensers and battery), but you would likely feel it.

This is the drawing of the Sparton patent, after WWII and not after WW1 as mentioned before.
Sparton_horn_surge_clipping.jpg
Sparton_horn_surge_clipping.jpg (53.79 KiB) Viewed 724 times
At that time they were using selenium diodes, known to smell like rotten eggs when burned (H2S) :D !
Pdease note that the silver ring marking side of the diode has to be connected to the (+).
In the patent schematic it looks like they have the positive wired to the ground.


You should ask for a +/- 110V 5W power silicon diode to put across the horn terminals
This is a component like that:
Diode_surge_clipping.jpg
Diode_surge_clipping.jpg (20.95 KiB) Viewed 724 times
It will act as a surge protection, as explained in the Sparton patent shown below.

But this is not necessary to resolve your current issue.
Yves

What was written in the Sparton patent :
Sparton_diode_patent_1956.jpg
Sparton_diode_patent_1956.jpg (116.49 KiB) Viewed 724 times
Ford GPW 164794 1/4T 12-7-43 - Frame# GPW*239762*
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