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'64 TV3 with original electrics: Horn?

PostPosted: Thu Sep 10, 2015 5:09 pm
by 911hillclimber
Have everything electrical working on my restoration except the horn.

The volts are at the horn from the new regulator and the white wire from the horn to the switch goes to earth when the horn button is pressed, bells through using the meter.

No horn sounds on a cheap 6v DC horn off ebay..
The original is kaput.

What have people used please as a replacement?

I am doing the electrical checks without a 6V battery (if that makes any difference)

Re: '64 TV3 with original electrics: Horn?

PostPosted: Thu Sep 10, 2015 5:14 pm
by Captain Pugwash
I've stripped and rebuilt DC horns when I've had to, but lambretta DC horns are usually adjustable with a screw on the back and a lock nut and stud front centre.

Small adjustments on the rear screw usually bring the internal switch back into its working position.

The horn works by an electrical magnetic pull on the front metal part of the horn the sound is made because when the metal pulls rearward the switch turns off the power so the metal piece resumes its original position.

The fact that the switch and magnetic pull happen many times a second causes the metal to vibrate that creates the sound.

If the switch doesn't switch off the magnet then the horn doesn't work as it should , instead it usually just clicks and short circuits.

But if the horns electromagnetic internal coil is damaged then no ammount of adjustment will make the horn work.

Hope this is some help.

Re: '64 TV3 with original electrics: Horn?

PostPosted: Thu Sep 10, 2015 5:44 pm
by 911hillclimber
Thank you for your comments, all helpful!

I cannot get a squeak from the horn and out of curiosity have had it apart. The two contacts in the inner black moulding seem to be in permanent contact but not adjustable.
The only adjustment is the front center 'bolt' but that achieved nothing.

Looks like SRest have a horn, £30 + all the trimmings..

Re: '64 TV3 with original electrics: Horn?

PostPosted: Fri Sep 11, 2015 7:35 am
by CHRIS in MARGATE
Post in the wanted section but specify AC or DC Horn.
Also a great source of parts is the Facebook page "Lambretta for Sale"

Re: '64 TV3 with original electrics: Horn?

PostPosted: Fri Sep 11, 2015 8:48 am
by 911hillclimber
Thanks Chris, tried Wanted on here before, but no responses.

Also, not sure if the horn should be AC or DC!

Electrics are 6V 6 pole standard spec with battery and 2 x yellow wires to the regulator. MB Dev site states this is a DC with battery system.
The wire loom diagram in Sticky's book is "TV DC with battery" so I presume it is a DC horn....(?) :roll:

I have been testing the electrics with the engine running but no battery.

Re: '64 TV3 with original electrics: Horn?

PostPosted: Sat Sep 12, 2015 2:30 am
by rossclark
The horn should be DC, might be worth testing it just with a battery

Re: '64 TV3 with original electrics: Horn?

PostPosted: Sat Sep 12, 2015 7:09 am
by 911hillclimber
I don't have a battery yet for the TV yet, but have connected my battery charger @ 6V to the horn, not a peep or a rattle.

I think the SR CASA one is the way to go, just another £35!

Re: '64 TV3 with original electrics: Horn?

PostPosted: Tue Sep 15, 2015 6:50 pm
by lammytv200
My horn on my 63 tv only works with the battery connected.

Re: '64 TV3 with original electrics: Horn?

PostPosted: Tue Sep 15, 2015 10:43 pm
by 911hillclimber
Interesting!
The CASA horn will be with me tomorrow. The loom all rings through with the engine running and not, but I need a battery now so need to find one locally as most seem to be shipped dry and you need to get it filled etc.. :roll:
With this fixed I hoe I can get the TV off to Reed speed for an MoT, registered and up for sale!

Re: '64 TV3 with original electrics: Horn?

PostPosted: Wed Sep 16, 2015 6:23 pm
by nickw
Check out eBay. I've bought a few batteries off there in recent years same size as Lambretta battery but filled with gel. Not sure of the size you need so can't help there but someone else will know on here. If I get the chance I'll find the info and report back :-)

Re: '64 TV3 with original electrics: Horn?

PostPosted: Wed Sep 16, 2015 10:37 pm
by rossclark
Yes the standard battery is something like a YB5 but look for a gel or sealed version on eBay.

Re: '64 TV3 with original electrics: Horn?

PostPosted: Wed Sep 16, 2015 11:04 pm
by 911hillclimber
Thank you, ordered one from a motorbike battery specialist this morning, £32, right size and rating for the TV.
Horn also came today, so TV will soon be ready for the MoT.