Snipping USB and VGA cables. Go on, dare me...

demonboy

demonboy

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I'd like to eliminate some annoying bulky connections on my extension cables, one of which is male/female USB and the other is male/female VGA. What's to stop me cutting the ends off and just wiring the bare ends to their respective cable?

I seem to remember reading somewhere that it's not that simple when it comes to USB, yet all I can see on my transparent USB is five colour-coded wires. Four are pins and the fifth is the outter casing.

Looks pretty straight forward to me, but then the last time I said that.......
 
Don't see any problem. USB is just serial data with max 5volts (or so) on the wires; and VGA is video level signals. Just make a decent job of the "screen" if there is one.

Go for it!!

Alan.
 
Hi Demonboy,

certain cable that require bandwidth i.e. data cables etc are if I recall impedance matched, perhaps which if wrong length like an antenna may reduce the actual data transfer rate. I would keep a service loop in it and hide if you can. Cant remember the exact terminology.
Hope this is of some use.
 
You can cut USB and VGA cables with no problems. How are you going to terminate them? If splicing, then you need to cut back the insulation to expose about 5cm of braid on each side. Thread a bit of 8mm heatshrink over the whole cable. Pull back the braid, and thread a bit of 2mm heatshrink on each core. Then solder each core, and shrink over. Finally, pull back the braid from each end so they overlap (a bit of solder can be used), then shrink over.
 
That's what I was thinking of doing, Nigel.

Impedence matched cables is a fair point but negated by the fact I'm terminating each end to what was a matching cable set anyway. It might explain why, however, my radar didn't work (trying to match new cables with old).

Got my sparky coming over later so will chat to him about it too. Thank you for the replies. I'll let you know how I get on.
 
I think you'll find this won't affect the impedance. This is determined by the cable construction, diameter e.t.c.

The length of the cable will affect the loss and the delay; this could be important for a radar cable where the delay may form part of the calibration.

A bad connection may give you a poor VSWR but for USB and VGA we are talking about low data rates and low power ............. so I don't see the problem.

Alan.
 
Here we go with impedance matching again!

The only cables on a boat that are impedance matched are to transmitting antennae. Even then, they can be cut as required because the cable itself has the same impedance no matter what the length.

Problems can only occur if a cable is not the correct impedance, and is part of a tuned circuit.
 
Yeah, and that's my radar problem. Trying to connect a new cable to an old one.

The VGA and USB cables are a separate project, nothing to do with the radar. I was dubious about snipping the cables because they are attached to a unit that I can't replace here in Turkey if it all goes tits up.

Now another question about the colour coding of a USB and VGA cable - basically, are they colour coded? Are the black, green, white and red cables the four inner cables in a USB plug, with the silver one being attached to the casing? Is this standard? Same question with VGA?
 
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