Speaker cable for power

T

timetrap

Weaksauce
Joined
Aug 28, 2004
Messages
64
Hi guys,

I'm curious to know what kind of wire I should use to extend the current length of the existing cable on an LCD mod I'm doing. I've heard that thick speaker wire works just fine for this purpose, but I'm curious if this is accurate. The load on the wire will be somewhere around 24 VAC and under an amp. Anyone have suggestions, or can someone correct me if I'm hazardously wrong? it would also be helpful if anyone knew the limitations of speaker cable, or exactly the minimum awg I would need.

TIA.
 
It depends on how long you are planning on extending the cable. Regular wire like the kind coming from your PSU should be fine. <runs to check spare wire> It's 18AWG.
 
yea, it'll work just fine, exspecially for short distances.
 
About anything 24 guage or larger will work. Depending on length, ventilation and such you could probably even go as small as 30, but I don't receomend it unless you really need small wire as it's usually best to derate a bit.
 
Thanks for the help guys.

If you could help me with one other thing - the whole point of this is that I picked up a 4" LCD TV for $25, and it's got a connector for power but didn't come with a power supply. It takes 24VAC at a little under 500mA, so today I bought an adapter at a local store for $3 that has those specifications. I snipped the end off and am going to attach a new connector so that the power input on the LCD and it can connect nicely. Since I'm an idiot at electronics, I have a question. When I cut the end off, I saw that there were three cables - one red, one black, and one white. I know the red is the positive, the black is the negative, and I'm assuming the white is a ground. Afterall, the connector on the end of the AC adapter is three pronged and has the ground, so that makes sense. The only issue is that there are only two wires coming out of the LCD, and no ground. Do I need to use this white wire or can I simply heatshrink it off and be done with it?

Once again thanks for all the help.
 
Are you posisitve that the power input for the LCD is AC? I've never seen one with an AC power input, only DC.

And if the Adapter you have does in fact have an AC power output, there will not be a positive nor negative wire, because the whole point of AC is it changes polarity. Plug your adapter in and start measuring voltages between wires in AC and DC mode to figure out what the wire colors mean. But your guess about what the wire colors means sounds right to me.

Is there any metal case of the LCD exposed? If so, you would attach a ground to that. If not, it doesn't need grouding.
 
Thanks for the reply. Yes I'm positive that the unit takes AC, I thought it was wierd as well but that's what it takes. This isn't a normal LCD - it was designed to be used inside slot machines at casinos in Japan according to the salesperson. I especially like what it says on the front - "Please enjoy your fun time as much as you like with your own way." Not exactly the best English, hehe. The guy at the store had a couple identical units on display and they were running off a 24VAC 500mA adapter, so I plugged mine in to see if it would work okay. It worked beautifully, the TV is of great quality and it goes all the way up to 120 channels on cable. I then went out and bought a similar adapter, as you can see in the pictures below. Thought they might help you get an idea of what I'm talking about.

lcdtv.jpg


info.jpg


backlcd.jpg


adapter.jpg


As you can see in the pictures, the power cable from the unit is 16AWG or thereabouts and since there's only two, I should be able to attach the white wire from the adapter to the metal of the case, then. Sound right? My multimeter is broken so I can't test out the voltages unfortunately. What should I see if everything is okay assuming I can borrow a friend's multimeter?
 
Very Interesting unit. Sounds like a lot of cool things you can do with one and pretty cheap too... Have fun, looks like you sorted things out...
 
Of the three wires, one should have 24VAC between itself and both of the other wires. That is going on the monitor's input. One wire will have continuity with the ground pin on the wall plug, That wire goes to the metal casing. The last wire is the other one going into the monitor input.

For the two wires going to the monitor's power input, they can be in any order.
 
Thanks for the help guys. Ignore my hack job on the saudering.


solder.jpg


overheadview.jpg


success.jpg


Now I can finally finish my mod. :D
 
lol, I just noticed that. Perhaps not the smartest thing. I was actually doing the work in the kitchen and a couple plugs are shot there, so to test it out the first time I brought it into the bathroom where I knew that the plugs worked. :)
 
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