[sdiy] J-Wire keyboards

[Tom Wiltshire]

I don't know about J-wire keyboards in general, but I can tell you  
about the one in my Pro-One.

The Pro-One does use a scanning matrix.

The keyboard keys have a plastic 'spade' underneath them with little  
holes in. The J-wires are short lengths of wire (presumably some  
metal that doesn't tarnish if they had any sense) about 2" long that  
go through the little holes in the spades and stick out a bit beyond  
them. When you press the key down, this wire contacts a buss bar  
underneath. Since the Pro-one uses a scanning matrix, the buss bar is  
broken into short lengths connected with rubber sleeving, rather than  
being one continuous piece. It *looks* like a single buss, but it isn't.
It's a very mechanically simple system, and consequently one of the  
most reliable keyboards I've got. The only problems are that the J- 
wires can get bent, but this can only happen when you've got it  
apart, so be careful when servicing, and that sometimes the buss bar  
or wires need cleaning. I use tape head cleaning solution for this  
which seems to work fine.

HTH,
Tom

On 28 Jan 2010, at 14:37, Ian Smith wrote:

>
> Hey all,
>
> This came up in my previous thread. What is a J-wire keyboard? How  
> does it work? From what little information I can find, it looks  
> like a single buss keyboard not a scanning matrix. Does it work  
> with reed switches like Ray Wilson's single buss keyboard or is it  
> something else entirely?
>
> -Ian (have a keyboard but no guts for it) Smith 		 	   		
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