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Clamshell video out
Posted by: tomlee59 on 2009-08-11 12:51:49
I've just acquired a beat-up firewire clamshell -- the screen is cracked, and the rest of the poor thing looks like it was run over by a truck (for all I know, it was). Other than that, I can hear the startup chime upon power-up, so maybe it has some life left in it.

This clamshell has composite video out. I'm curious: Do any of you know offhand if that output is active on boot-up by default? (Yes, I'd eventually try it, but if someone here already knows the answer, then it would potentially save me a little time.)

Thanks in advance, mates!

Posted by: Hrududu on 2009-08-11 15:40:11
I think if you boot it up while connected to an external screen, it will work. Unfortunately, my clamshell's sound/video is completely fried so I can't verify it for sure.

Posted by: Mars478 on 2009-08-11 15:45:13
Yes it will work. You need to make sure you are using an Apple AV Cable, a generic one will not work. I have tried it with my graphite clam, and it just makes a distorted audio output.

Posted by: tomlee59 on 2009-08-11 22:41:47
Yes it will work. You need to make sure you are using an Apple AV Cable, a generic one will not work. I have tried it with my graphite clam, and it just makes a distorted audio output.
I'll likely be wiring up my own cabling directly to the appropriate pins on the jack, so that won't be a problem. I just needed to know if the composite output was always active. If not, that would have presented a bit of a chicken-and-egg problem. I'm happy to hear that I don't need the main display to work in order to get the video output to function. Thanks!

Posted by: Christopher on 2009-08-12 15:48:31
I remember hearing around in the apple discussions that you can use standard a/v to headphone style cable, it's just that the colored composite cables are switched around. For instance, yellow could be left stereo channel, while red could be video.

It's a guessing game, but it's cheaper then buying effectively the same cable.

Posted by: Mars478 on 2009-08-12 15:52:56
Ohhh I am trying that now. Be back with results.

Posted by: coius on 2009-08-12 23:51:11
I seem to recall that when I had one, the AV Cables had a longer mini-jack that had an extra pin. Supposedly to take video output, and then they all had a common ground.

You will most likely need an Apple AV Cable for a reason. Unless you can find a 4-ringed jack, I am afraid you are SOL.

Hope this helps!

Posted by: Mars478 on 2009-08-13 05:11:34
Nope. It does not work. A four ringed Sound jack is avaliable on the iPhone Headset. the iPhone uses an extra one for controls.

Posted by: tomlee59 on 2009-08-14 13:08:00
Since the output consists of two stereo channels and one composite video line, there have to be four connections. A standard stereo headphone connector can't work -- it has to have four contacts (tip, ring, sleeve and ground).

It's risky randomly sticking connectors into things -- grounding an output can kill circuits quickly.

Posted by: luddite on 2009-08-14 14:00:39
I have the Apple AV cable and I can confirm that the plug is slightly longer than normal and has 4 contacts... I'd guess it has to be since the jack on the clamshell supports a standard 1/8" stereo plug for headphones. Presumably the tip of the plug carries the video signal.

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