I think that listed 'condenser' would be the one in the distributor - other condensers/capacitors on various electrical items are for radio noise suppression, useless if you don't have a radio - can't think of any other reason a horn would need a capacitor and you don't see any shown on wiring schematics except in the accessory radio instructions, but I've never seen one in a horn circuit
"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir "When we tug a single thing on an old truck, we find it falls off" ~ me Some TF series details & TF heater pics
Bill if you take the horn apart, there is a flat paper wound condenser in there, it's part of the LC circuit and determines what the circuit will resonate at. To small and the tone will be to high, to large and it will be to low. Don't know what just right is but it shouldn't be to difficult to try a few to see what sounds best, they're dirt cheap. But you are correct about the .2mf cap listed, it's the one across the points in the distributor. DG
"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir "When we tug a single thing on an old truck, we find it falls off" ~ me Some TF series details & TF heater pics
I am also trying to repair my horn on my '39. It makes a momentary muffled "breep" when you push the button. I found the wires on each end of the condenser not connected. I tried to solder them using the proper soldering techniques and they wouldn't take. Crimped the wires to a ring terminal and screwed them into the condenser. Same sound as before when pushing the button. Can a regular modern capacitor be substituted, and what value? Hope someone can help. New to the forum. Troy
Check out the earlier replies Troy. A trip to your local Radio Shack store for a handful of caps will only cost you a couple of bucks. Modern caps are much, much smaller than the old paper one used in the Klaxon horn. Do a little experimenting if you need a replacement. Before replacing the cap I'd try making some adjustments, that's what it sounds like is your problem. If you are getting a buzz then the LC circuit is working and an adjustment may be all that is necessary.
Hey Troy, let us know what you find out. Every little bit of information posted here may help the next guy, you know.
Next time I have my Klaxon horn off, I'll measure the capacitance, this has come up many other times and a capacitor is a capacitor, so replacing it with a much smaller, much better modern one certainly has a place here.
Please keep us informed on this. A Radio Shack part number would be great! I am in the same boat. My 1940 horn had one of the wires come loose. I tried to solder back on, but it would not take. I replaced with another horn for now, but would like to put the original back on.
I know this is an old thread, but wonder if the capacitor info was ever posted. Been searching otherwise for a source and part number so I can order one to repair a horn. Thanks.
This is something I collected from the WEB regarding replacement capacitor for our horns. I have not used one of these & do not know if it really works. If you try this please post your results for the benefit of other Bolters. Harold
i don't have the horn capacitor value in my list of truck capacitors
points cap: 19106636 1869704 1869706 0.2 uF
with regards to noise suppression when installing the radio: on voltage regulator BAT pin 1912900 0.5 uF (3-1/8 inch lead) on generator ARMATURE terminal: 1911095 0.3 uF or 1910147 0.5 uF on ignition switch side of ignition coil: 1930274 0.3 uF or 1910147 0.5 uF on back of instrument AMP meter: 7257919 0.5 uF
when it comes to capacitors in these truck circuits, 10 or even 20% is usually close enough todays standard values are 0.22 0.33 0.47, but some automotive specific capacitors come in any oddball value still
i'll see if i can track down information on that horn capacitor, i'm curious now -s
alright,...i found information regarding antique horns of this type, the capacitor in the horn is typically 15 uF, much larger value than the bypass capacitors found everywhere else in the truck.
the horn must vibrate within a tighter frequency range to allow the tone disk to resonate and produce more sound. the capacitor in the circuit makes the operating frequency of the diaphragm and armature much less sensitive to a change in operating voltage (engine on vs off, headlights on, bad generator...etc) -s
Digi-Key. You can select filters to search capacitors by type, voltage rating, capacitance value and tolerance, and so on. Pay attention to the minimum order quantity, as some aren't available as individual units. Play around with their search and filters, and you will find what you need. Here's one, a tantalum capacitor by way of example, arbitrarily selected at 50V rating. There are some cheaper in other voltage ratings, around $2. Or you might have luck on Amazon or eBay.
well ideally you want a metalized film type, however if you find an good quality aluminum electrolytic (low ESR) and are mindful of the polarity that could work and will be much smaller than a film type
how much space do you have to work with? it's difficult to gauge from the photo
at Digikey i found this one: Illinois Capacitor part# 156MWR100K, it's 21 mm dia. by 34 mm long, $6 but shipping will double that also work browsing Arrow.com and mouser.com to see if they have a better option in stock -s
Before I order this capacitor replacement, the link offered earlier shows a different size .56microfarad 100volt instead of the 15uf 50volt. Which is the correct one to order?
15 uf. The polyester thin film cap as suggested earlier by 2Many isn't polarity sensitive like an electrolytic or this Tantalum is, and should have good voltage safety margin at 100V, so would be a good choice.
If you search around the Digi-key site (or Arrow or Mouser), you may be able to find a similar cap at a lower price. Pay attention to the minimum quantities, as some parts require bulk buys from the distributors.
hi 46Sparky, a smaller value like 0.56 uF would make more sense than the information i found about rebuilding Lucas Klaxon horns elsewhere a 15 uF in the 50-100V range in the old horn would have been a much larger physical size, so either they are mistaken or the circuit only requires a minimum value and they are doing over-kill.
the old one has no markings on it? do you have a way to measure it? sometimes the old paper caps can miraculously be good as long as you have a way to measure it's capacitance and leakage? i've had luck baking the parts overnight at elevated temperatures, go hot, well over 150F, like closer to 200F, drive out all moisture. -s
haven't noticed them in the TF horns, hafta check again