Video Plug help please!!

[Jesse]

Hello all,

I have a problem. I have a simple video switcher I purchased. I am using
it with a projector. What I need to do is generate a black video signal I
can connect to one of the switches 4 inputs so it outputs black video to the
projector. I have been told that soldering a 75ohm resistor to a composite
plug(center to ground) and plug it into an input will generate a black
signal. Is this correct? If not, what is the easiest way of accomplishing
this?


Thank you in advance,

Jesse

 

[Ken Taylor]

Hello all,

I have a problem. I have a simple video switcher I purchased. I am using
it with a projector. What I need to do is generate a black video signal I
can connect to one of the switches 4 inputs so it outputs black video to the
projector. I have been told that soldering a 75ohm resistor to a composite
plug(center to ground) and plug it into an input will generate a black
signal. Is this correct? If not, what is the easiest way of accomplishing
this?


Thank you in advance,

Jesse

Assuming that the connector is a BNC (seems most likely) then just go and
buy a 75 Ohm BNC termination from a parts supplier or radio or video store.
Frys Electronics have one which is F-type connector if that's what you have:
http://shop4.outpost.com/product/1525076
otherwise Arrow (www.arrow.com), just for one, have them.

Ken

 

[Jesse]

Thanks Ken

And just to make sure, that will generate a black signal on the screen so
the projector wont say "No Source Detected"

Once again,

Thanks

 

[John Jardine]

Hello all,

I have a problem. I have a simple video switcher I purchased. I am using
it with a projector. What I need to do is generate a black video signal I
can connect to one of the switches 4 inputs so it outputs black video to the
projector. I have been told that soldering a 75ohm resistor to a composite
plug(center to ground) and plug it into an input will generate a black
signal. Is this correct? If not, what is the easiest way of accomplishing
this?


Thank you in advance,

Jesse

Sorry but this isn't much help but shows it's not difficult ...
My monitor prints "NO SYNC" with no video input. I generated a pretend sync
using a CD4093 quad schmitt. Basically just a gated couple of oscillators
and summing resistors, no great precision. The monitor just thinks it's
seeing a Black picture.
(I no longer have the unit or it's circuit. )
regards
john

 

[Rich Grise]

Thanks Ken

And just to make sure, that will generate a black signal on the screen so
the projector wont say "No Source Detected"

No, it won't. It will generate a "No Source Detected". A black signal is not
the same as no signal at all, you see - it would have to have all the sync
pulses, just like a TV picture where you've left the lens cap on the camera.

i.e., to really do it right, you need more than just a terminator. There
used to be sync generator chips, but I don't know if anybody even still
makes them.

Good Luck!

REF ---v

 

[Jim Thompson]

No, it won't. It will generate a "No Source Detected". A black signal is not
the same as no signal at all, you see - it would have to have all the sync
pulses, just like a TV picture where you've left the lens cap on the camera.

i.e., to really do it right, you need more than just a terminator. There
used to be sync generator chips, but I don't know if anybody even still
makes them.

Good Luck!

[snip]

Fairchild 74ACT715 ??

...Jim Thompson

 

[Jesse]

No, it won't. It will generate a "No Source Detected". A black signal is not
the same as no signal at all, you see - it would have to have all the sync
pulses, just like a TV picture where you've left the lens cap on the camera.

i.e., to really do it right, you need more than just a terminator. There
used to be sync generator chips, but I don't know if anybody even still
makes them.

Good Luck!

[snip]

Fairchild 74ACT715 ??

...Jim Thompson

I found the semi-conductor online and it is exactly what i need. Thank you
very much everyone!!!!!

Jesse