ice cream van chimes

[nembis]

got a set of ice cream van chimes and they have been wired in wrong (half due to the fact that without opening the box there is little way to tell which are the power leads and which leads lead to the speaker) as you can tell im not electronics expert, hence my visit for help here.

anyway it looks like the audio transformer is blown and im finding it tricky to source a replacement it is part number.

stab-trans  part no 10360.

[james_s]

It may well be a custom part, fortunately it's probably not difficult to rewind it. Was DC power wired up to the transformer secondary?

[nembis]

Cant see it being a custom part. Only maybe 200 will be sold a year. Not the value in the buisness to have custom parts i would think

[james_s]

Well are any of the windings intact? If you have the dimensions of the core you can get an idea of the power handling, then if you look at how it's driven you can get an idea of the primary specs. It's possible that it's some kind of off the shelf audio matching transformer.

[floobydust]

If it's the audio output transformer, it could be an off the shelf 50/60Hz part. They'll work for audio, as far as chip tunes. I have no idea how many watts you need for an ice cream truck. Do you know the horn speaker's impedance?
Stab-trans is still in business, you could ask them for a datasheet.

[nembis]

Tried to load a couple of photos there but wouldnt accept as unaccepted format. I will get my friend thats looking to repair it to join. He knows more than i do about it. Best regards and thanks all for your help.

[MrWhippy]

This is the part required

[james_s]

I can't really see much from that picture, could you get one with a bit higher resolution? Does the transformer look burned?

[MrWhippy]

Yes it’s burnt on one side .. the chimes work but very low volume hence why I’m presuming it’s the transformer . I have checked the tip3055 power transistors and are both fine . The transformer has 6 wires . 2 of which go to the power transistors . Two red together goto fuse . And 2 black to negative

[floobydust]

Can you give a picture of the transformer label on top.
I think it's an ordinary power transformer connected backwards. But the horn speaker might be 16 ohms.
If the speaker-end was accidentally connected to 12V power, it would eventually roast the transformer winding.
More pictures help.

[MrWhippy]

The label on the top says stab-trans part no 10360 . I have contacted stab tranns but they are talking £100 for 1 as they only normally sell in bulk . I have traced the wires from it . It has 2 small black wires that go to the middle leg on the power transistors . 2 yellow that are the speaker output wires and 2 red which are soldered together which are positive . The volume is very low on the amp and can’t see anything else that’s burnt out apart from the transformer that is burnt on one side

[james_s]

Have you asked them for a datasheet? That would provide the information needed to locate a substitute.

[james_s]

What generates the tunes on these things anyway? Is it an off the shelf melody generator, or some kind of epoxy blob IC?

A few years ago I remember a strange icecream van experience. I was at a park in the middle of summer when one rolled through, something seemed a little odd and then I realized it was playing a christmas tune. Then I actually looked at the thing and saw that it was a completely beat to crap minivan, I've seen nicer looking vehicles in junkyards.

[nembis]

That van was still probably worth 10k a new ice cream van sets you back about 120k uk ie 170k usd.

Not sure what does the tunes. There are 64 diffrent tunes onboard some are single tune wind up tunes ie mechanical.

The chime boxes the 64s are not made anymore only 32s and 16s and less, many just a dingle chime. The company that makes them. (Only 2 companies in the world) no longer repair them. They prefer to just sell you a new one. Single chime maybe £360 each. That to repair any that break. Hence trying to look for a repair solution here. The 64s are starting to get quite rare.

[fzabkar]

The local ice cream van has a "ding ding" chime that reminds me of that scene in Monty Python's Holy Grail where Eric Idle is pushing his cart during the Black Plague and calling out to people to bring out their dead.

BTW, photos would really help.

[NiHaoMike]

I'm surprised they're not just using an off the shelf car audio amp connected to some outdoor PA speakers.

[fzabkar]

I'm surprised they're not just using an off the shelf car audio amp connected to some outdoor PA speakers.

I was thinking of retaining the preamplifier stage and replacing the output with a mono class D power amp module, eg …

https://www.ebay.com.au/itm/DC-12V-24V-TPA3118-BTL-60W-Mono-Digital-Audio-Power-Amplifier-Board-Module-Kit/223227437118
http://www.ti.com/lit/ds/symlink/tpa3118d2.pdf (datasheet)

The total cost would be around AU$5.

[james_s]

That van was still probably worth 10k a new ice cream van sets you back about 120k uk ie 170k usd.

Not sure what does the tunes. There are 64 diffrent tunes onboard some are single tune wind up tunes ie mechanical.

The chime boxes the 64s are not made anymore only 32s and 16s and less, many just a dingle chime. The company that makes them. (Only 2 companies in the world) no longer repair them. They prefer to just sell you a new one. Single chime maybe £360 each. That to repair any that break. Hence trying to look for a repair solution here. The 64s are starting to get quite rare.

Maybe over where you are, but here a beat to shit mid 90s Ford Windstar minivan isn't worth squat. Most ice cream vans here are bog standard fleet vans that have been outfitted with freezers, a music player and some decals on the side, not custom made vehicles.

I was curious about the music players since they all seem to sound identical. I bet something comparable could be made with an 8 bit micocontroller and a cheap audio amplifier module.

[floobydust]

OP, you need more info on the transformer. If Stab-Trans will say anything for volts in/out or turns ratio etc. then a replacement could be found.  Guessing at least a 1:2 turns ratio with 8 ohms.
Low volume could also be caused by using the wrong loudspeaker impedance. It should be a horn speaker or two, on the van roof, anywhere from 4-32 ohms.

Modern ice cream van kits are using MP3 players and compact Class-D amplifiers, so they are small and low cost- less than remaking a custom transformer: http://icecreamtruckhorns.com/product/ice-cream-truck-horn-kit/. The "ice cream song" is “Turkey in the Straw” but other songs are on the site.
It's just a generic 12V MP3 player out of china avaialble on eBay or Ali.