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
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
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
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
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
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
The switcher may well be boosting the signal. Feed in a 1V peak to peak sine and measure the output.
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
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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