| SRMcGee |
Folks:
Please forgive the newbie stupidity, but I have a wierd problem.
I have a television that has inputs for only 1 separate source device (the imputs are R & L channel audio and Video In. This set is not hooked up to any cable inputs. I have 3 devices that I'd like to plug into the TV -- a DVD player, a VHS player (yes, the kids still use it) and a Gamecube. I built a small switchbox with a 4p4t rotary switch that switches between the 3 devices (and one null setting). Ground is also switched -- all 3 grounds (R, L & Video) for each device are tied together and are connected to the output grounds when that input is selected. I have checked all of the connections using a multimeter and get the expected results (no resistance between the selected inputs and outputs).
Here's the problem: there is no video signal. I know that video is going into the box and is being routed appropriately, but nothing comes out. Audio works fine, regardless of which of the 3 inputs for each device I select.
Is there a reason why video cannot be switched in the same manner as audio?
Thanks,
Scott |
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| Frank Berry |
You should be able to switch video as easily as audio.
Perhaps there is a short-to-shield on your video output cable or connector.
Temporaily use one of the audio paths to carry video.
If the video is good, you'll know there is a problem with the video cable or the wiring.
Frank |
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| SRMcGee |
Frank:
A good suggestion, but it didn't work. The two audio channels work regardless of which of the 3 RCAs allocated to each device that I use. Video seems to fail no matter what.
Any other thoughts?
Regards,
Scott |
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| pinkmouse |
| The switcher may well be boosting the signal. Feed in a 1V peak to peak sine and measure the output. |
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| moamps |
Hi Scott,
The main difference between the audio and video signal is a much bigger frequency bandwith of the video signal (up to 5MHz). From your earlier posts, I'd say your switcbox is a passive type and audio is routed correctly. The video signal may be internally routed with an unappropriate cable or/and cables may be too long, thus causing significant video signal loss.
If you can, please post some pictures of the inside of the switchbox.
Regards,
Milan |
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