matt freeman Posted November 5, 2006 Share Posted November 5, 2006 in an attempt to plug both a VCR and a DVD player into one projector, it seemed a perfectly good idea to create a very simple change over switch, (DPDT) with 2 inputs, the switch and one output. (yes just plugging the other one into the wall box would be simpler, but we are dealing with possibly incompetent teachers) having built the switch, they work fine with just running a current through (as a test, I wired it up to 2 LED's and used it to switch between the two, which checked that it was indeed switching between the two) however when actually connected to a video source, it doesn't do anything at all. I'm assuming I must need a "video quality" switch or something like that. but I couldn't find one on rapid electronics website. anyone point me in the right direction for the switches? Matt Link to comment Share on other sites More sharing options...
paulears Posted November 5, 2006 Share Posted November 5, 2006 nope - something is adrift. a dpdt style toggle will switch video - they are not constant impedance devices so they are not really suitable, but they work ok on most shorter runs - as proof, you can buy a scart to phono adapter with a switch to select input or output - this uses a very crude dpdt slide switch. In your case, have you made certain the switch is actually functioning - the current required for led testing may not be representative of allowing a 1v p-p video signal to pass. a straight resistance test would be better. If there is dc continuity all should be well. One thing could be if you have shared the video grounds - and just switched the centre conductor. It shouldn't make a diference, but worth checking in case the issue is some kind of floating level issue? Link to comment Share on other sites More sharing options...
broadcast_techie Posted November 5, 2006 Share Posted November 5, 2006 I have made a nice simple 'opt out' switcher using wafer switches and standard equipment cable.... attempted to use coax, but was more trouble than worth, and box worked fine... easy solution: http://www.maplin.co.uk/Module.aspx?Module...ch&doy=5m11 Kris Link to comment Share on other sites More sharing options...
matt freeman Posted November 5, 2006 Author Share Posted November 5, 2006 thanks for that, ill check the continuety of teh switchs tomorrow. if they dont work, ill try some better dpdt switchs. broatcast technician: dont talk to me about coax being more trouble than its worth, I spent ages finding coax that would work for a green room feed, after long testing, almsot every peice we had had continuety between the cores (this was met by alot of rude language, and a fair ammount of panic.........but dispite the cores being connected, the cable still worked. Link to comment Share on other sites More sharing options...
jayselway Posted November 6, 2006 Share Posted November 6, 2006 I had a similar problem with a Scart switcher - Manual with the push buttons to select the required input. It was ok with 2 cam's running, and flicking between the two, but the DVD player wouldn't show up through it. Link to comment Share on other sites More sharing options...
matt freeman Posted November 12, 2006 Author Share Posted November 12, 2006 it works! woo, im so good.(after a large ammount of multimeter testing, and realisation of alot of really stupid faults) oh well, learn's from mistakes, and goes to sit in a corner to suffer the abuse for such incapable soldering. Link to comment Share on other sites More sharing options...
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