VGA signal to LCD Problem

[kpratap]

Hello

I am converting VGA signal to CAT5 cable compatible for transmission over longer length and converting back to VGA near LCD monitor. When I connect VGA out of my laptop direct to the LCD monitor at 1280x768 @ 60Hz, picture is displayed properly on LCD. But when I connect the same video out to my device and connect LCD monitor to my receiver's output. The video is displayed properly only for 10seconds and some times even less and the screen blacks out for 1 or 2 seconds and then the picture correctly comes back again. I checked all the sync signals and timings. Everything looks correct to me.

Can anyone tell me why LCD monitor blacks out for 1- 2 seconds... Or could there be any problem with my boards??

Your help is appreciated.

 

[RetroTechie]

Welcome here kpratap! :smile:

There's a big difference between the use/type of signal that usually goes over a CAT5 cable, and raw VGA. So it might help to know what that conversion entails, what kind of technique you're using / what circuit(s) you have on both ends of the cable.

Also: please define "longer length", as far as I know there's VGA cables up to 10 metres, possibly longer. Are we talking 20m? 50m? 100m? More? Why you have VGA signal source & monitor so far apart?

 

[kpratap]

Welcome here kpratap! :smile:

There's a big difference between the use/type of signal that usually goes over a CAT5 cable, and raw VGA. So it might help to know what that conversion entails, what kind of technique you're using / what circuit(s) you have on both ends of the cable.

Also: please define "longer length", as far as I know there's VGA cables up to 10 metres, possibly longer. Are we talking 20m? 50m? 100m? More? Why you have VGA signal source & monitor so far apart?

Thank You RetroTechie. :smile:

My circuit is based on the principles in the following link

**broken link removed**

But for testing for now, my CAT5 cable is not longer than 5ft.

This device can be used to distribute video from a computer to multiple screens at different locations. I have 4 outputs. I am testing only one for now.

I could not see any difference in signals between the input VGA at my PCB (from my laptop) and the output of my CAT5 receiver PCB. But the LCD monitor behaves as I stated in the above post.

If I can at least know the reasons why monitors behave like that, then it would help me in troubleshooting.

Thank you for your help.