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geekhack Community => Keyboards => Topic started by: reset on Mon, 23 December 2013, 14:29:25

Title: Unicomp "attached cable" compatibilty
Post by: reset on Mon, 23 December 2013, 14:29:25
Hi everyone.

I recently acquired a Model M with a frayed, non-detachable cable, and I ordered a replacement "attached cable" from Unicomp. Are these compatible? I have a limited knowledge of electronics, so I thought I'd ask you guys before I fry something.

As you can see in the pics, the wires on the Model M run (from left to right) black, red, white, yellow, while the ones on the replacement cable run red, yellow, black, and white. I apologize in advance if this has been covered. I searched, but couldn't find the exact info I need. Thanks for your input!
Title: Re: Unicomp "attached cable" compatibilty
Post by: tgujay on Mon, 23 December 2013, 14:31:33
Hi everyone.

I recently acquired a Model M with a frayed, non-detachable cable, and I ordered a replacement "attached cable" from Unicomp. Are these compatible? I have a limited knowledge of electronics, so I thought I'd ask you guys before I fry something.

As you can see in the pics, the wires on the Model M run (from left to right) black, red, white, yellow, while the ones on the replacement cable run red, yellow, black, and white. I apologize in advance if this has been covered. I searched, but couldn't find the exact info I need. Thanks for your input!

PS/2 had no standard for wire colors unfortunately, makes swapping cables a *****.  If it is from Unicomp I would suspect it is a direct swap, worst case scenario just use a multimeter to identify each wire.
Title: Re: Unicomp "attached cable" compatibilty
Post by: reset on Mon, 23 December 2013, 15:18:34
Thanks, tgujay! I swapped the cables & everything seems to be functioning normally.
Title: Re: Unicomp "attached cable" compatibilty
Post by: rowdy on Mon, 23 December 2013, 16:17:12
A bit late to the party, but I went through this while fabricating a replacement cable for one of my Model M.

http://geekhack.org/index.php?topic=45962.msg966400#msg966400
Title: Re: Unicomp "attached cable" compatibilty
Post by: reset on Mon, 23 December 2013, 16:38:46
Very useful, rowdy. Thanks for the link. If you didn't have a soldering gun, would simply twisting the wires together and covering with electrical tape work? Or is that too amateurish for long-term use?
Title: Re: Unicomp "attached cable" compatibilty
Post by: fohat.digs on Mon, 23 December 2013, 17:14:31
If you didn't have a soldering gun, would simply twisting the wires together and covering with electrical tape work?

That will work fine. As long as there is permanent metal-to-metal contact, you will have electrons flowing.
Title: Re: Unicomp "attached cable" compatibilty
Post by: reset on Mon, 23 December 2013, 17:53:41
Excellent, fohat. Thank you.
Title: Re: Unicomp "attached cable" compatibilty
Post by: rowdy on Mon, 23 December 2013, 20:31:22
The only other thing to consider with just twisting the wires is whether the cable will be under any stress.

I noticed that the original cable had the gromit permanently attached, like it was all part of the cable's rubber coating, or perhaps had been glued onto the cable (although the colour and material seemed exactly the same).  I had to forcibly cut the gromit off of the old cable, and the new cable is just sitting in it, a bit looser than I would like, but there is a bit extra cable inside the keyboard in case the cable gets yanked.

A soldered cable would better withstand the cable being pulled, if it is not otherwise held in place.