Pagoda SL Group

W113 Pagoda SL Group => Electrical and Instruments => Topic started by: Merc_Girl on January 08, 2024, 20:19:18

Title: Testing horn with multimeter
Post by: Merc_Girl on January 08, 2024, 20:19:18
Hi folks
Looked at a few threads but can’t find anything suits my query.

So, I have the horns removed from Bessie and want to check if the horns themselves have a problem.

I have a handy multimeter but no idea what bits to test and how 🙃

Is there an idiots quide anywhere would one know?

Many thanks


Title: Re: Testing horn with multimeter
Post by: rwmastel on January 08, 2024, 20:25:21
(Disclaimer: Electronics are a weak spot for me.)

I would think you would just provide a ground and then touch the other connector with 12v and Beep!!  Are you using the multimeter because you think you'll find too much resistance within the horn?
Title: Re: Testing horn with multimeter
Post by: Merc_Girl on January 08, 2024, 20:52:16
Using multimeter to check if circuit within horn working?
Title: Re: Testing horn with multimeter
Post by: DavidAPease on January 08, 2024, 21:46:56
Hi, Katie,

I doubt there's anything useful you can do with a multimeter to test the horn (at least without dismantling it). 

I agree with Rodd: Connect the ground side of the horn to the negative terminal of your battery (any 12 volt car battery), then use another wire to briefly connect the positive terminal of the battery to the other side of the horn connections.  It should beep (or honk...). 

If it doesn't, then it might be time to look inside, where the multimeter might be useful.

           -David

Title: Re: Testing horn with multimeter
Post by: Merc_Girl on January 08, 2024, 22:38:30
I’ve sort of already dismantled the horn, my curiosity got the better of me as I was intrigued as to why it weighed so much 🤓
Title: Re: Testing horn with multimeter
Post by: BobH on January 08, 2024, 22:51:11
The electro magnet is the only electrical part in there, it probably accounts for most of the weight

You can measure the resistance of the coil, if you select the 200ohm scale on the meter you should measure probably less than 10 ohms across the coil
Title: Re: Testing horn with multimeter
Post by: Cees Klumper on January 09, 2024, 13:55:24
Some horns have a small adjustment screw that regulates the 'resonation' of the membrane to produce sound, and slight adjustment of this screw can bring an old horn, that perhaps only produces a 'click' on activation, back to loud life.
Title: Re: Testing horn with multimeter
Post by: Merc_Girl on January 09, 2024, 17:52:04
Thanks chaps for useful info! Will start ‘playing’ at the weekend 😁

The disc thingy (membrane ?) didn’t appear to be screwed in on one horn , which I presume it should be given there is a screw thread on the end of the post it sits in?
Title: Re: Testing horn with multimeter
Post by: 66andBlue on January 09, 2024, 18:32:03
Hello Katie,
in Pagodaworld 21 (2017) I described the testing and tuning process that might be helpful to you. Do you have access to the article?
Title: Re: Testing horn with multimeter
Post by: rwmastel on January 10, 2024, 04:20:00
Mdsalemi restored a pair of horns.  Did you search the forums for others who may have?  They could be a wealth of info.
Title: Re: Testing horn with multimeter
Post by: mdsalemi on January 10, 2024, 14:50:09
Hello Katie,
in Pagodaworld 21 (2017) I described the testing and tuning process that might be helpful to you. Do you have access to the article?

PW#21 will be available to those that don't have it, in Pagoda World Book, Volume III (issues 21-30) which we will make available sometime later this year.
Title: Re: Testing horn with multimeter
Post by: mdsalemi on January 10, 2024, 14:54:47
Mdsalemi restored a pair of horns.  Did you search the forums for others who may have?  They could be a wealth of info.

I cheated. I read an article prior to Alfred's (66andblue) article. The horns contain a lot of proprietary parts that are simply unrestorable to mortals, but maybe to "makers" that like to fabricate things. I decided that completely accurate restoration was beyond what I started with. Onto "Plan B."

So, what I did was disassemble the horns, throw out the "guts", powder coat the clamshell cases, and install a new smaller Bosch SEALED horn within. Re-assemble with a Stoddard Motors kit. New tags. They came out beautiful, they sound great (though not the absolute perfect pitch) and look like jeweled treasures. Thus they never made it back onto the car! I couldn't do that to them. Living 6" from the ground, subject to all manner of road debris and water, would render them ugly too soon.
Title: Re: Testing horn with multimeter
Post by: Merc_Girl on January 10, 2024, 22:56:16
Thank you

I think I can get a copy through the members area

I’ll take a look, thank you  :)
Title: Re: Testing horn with multimeter
Post by: rwmastel on January 12, 2024, 21:34:04
Hello Katie,
in Pagodaworld 21 (2017) I described the testing and tuning process that might be helpful to you. Do you have access to the article?
I think I can get a copy through the members area
All the Pagoda Notes are available through Full Membership.  None of the Pagoda Worlds are.  Those are being compiled into the books and sold.
Title: Re: Testing horn with multimeter
Post by: Merc_Girl on January 13, 2024, 01:07:34
Thanks Rodd for clarifying 😁