Little Big Horn

[Architex_mA8tey]

Originally Posted by The_Laird

Just taken mine out and it's the earlier one too, part number 8L0 951 605. Is that interchangeable with 8L0 951 605A and, if so, what's the difference?

Mine is totally 'gubbed' though - all sorts of battery gubbins over the circuit board. Photos to follow.

It's interchangeable, I had an earlier one on my car originally which was changed twice, once for another cube shaped one and now I've got the later shape on there like your pic

[HPsauce]

Originally Posted by The_Laird

what's the difference?

Minimal I reckon, just a bit smaller and probably different batteries. "Plug compatible"
If my original was totally shot (it isn't) I'd probably buy a cheap used "A" on the basis that I'd cut it open and replace the batteries anyway. If it was corroded inside I'd just send it back for a refund.

[HPsauce]

Originally Posted by HPsauce

I'm off to Goodwood tomorrow for the breakfast meet

No interesting Audis there, but I did see this unique Humber Pullman (my crappy photo attached). Only 4 ever built and this is the only survivor.
See also: https://www.flickr.com/photos/61766673@N00/8206286706/

[HPsauce]

Originally Posted by David's8

The batteries (from reading the TT Forum thread) can be obtained from Maplin and soldered in removing the present battery holders and spring contacts.

I've been looking at this in a bit more detail, and the types of batteries available.
The actual space (with holders/contacts removed) is ideal for the typical 9V "PP3" battery and NiMh versions of these are readily available and the clips (with trailing wires) to fit the terminals are just over a quid from Maplin.

So would a 9V battery work? I've also seen 7.2V versions of a PP3 but they look to be very rare - used in radio control models I think.
Here's one in the USA: http://www.tnrbattery.com/varta-powe...lock-iec-6f22/

[HPsauce]

Originally Posted by HPsauce

I've also seen 7.2V versions of a PP3 but they look to be very rare

On the other hand this looks eminently useable, though only 150mah:
http://uk.farnell.com/varta/55615306...mah/dp/1879370

[The_Laird]

So, as mine (8L0 951 605) is gubbed (see piccies),and so is Brian's we discovered yesterday, and the later alarm siren (8L0 951 605A) can be fitted in place of the ealier 'square' one, can other similar sirens be used as well, such as 1K0 951 605C? It looks the same, comes from the VAG stable and has the same 3 pin fitting, but I don't really understand what the prefix and suffix numbers/letters mean.

We (me, Brian & David) were also wondering what on earth all that stuff on the PCB actually does, as all the other alarm functions seem to work fine without the siren. Anyone know?

[HPsauce]

That's a lot worse than mine, which was of course still working after a fashion.

I have an electronics designer as a neighbour who has offered to look at mine and advise on an appropriate battery solution, so I'll ask him what it does.

I guess the lesson is, regularly check it works and check for low voltage codes as well. At the first hint, get it out!

[The_Laird]

Brian's was even worse!

Can you ask your neighbour if he thinks similar sirens would work just the same? I'm thinking of getting a similar siren from a later car if they're interchangeable.

[HPsauce]

I'll ask, but doubt he'll know.
They clearly have "some" sort of signalling mechanism to enable the low voltage to be detected. If that's onboard later ones could have other cleverer stuff in them too.
Seems unlikely and pointless though.....

[The_Laird]

The whole box of tricks seems pointless to me. Something triggers the hazard lights to flash (without them having a PCB), so why not just trigger a simple horn? And does it really need a battery back-up?