Adding a composite input on a tv set

[avz]

Hi
I have an old portable tv set. it is not equipped with a composite (RCA) input and I would like to add it. could you please help me by telling me where should I connect it?
Thanx.

 

[kroni]

one possible solution would be using a hf-modulator to convert the composite / line signal(s) to hf and feed that into the hf-input. But maybe you can take a closer look on the boards in the tv set, chances are that signal connectors are named on the pcb... YMMV

 

[HiTech]

Usually you can tap in after the last video demod/buffer stage but I agree with the above reply that using a AV modulator is far easier and safer.

 

[mneary]

Televisions sometimes aren't isolated from the AC line. In that case, connecting directly could be deadly.

What's the model? A schematic would almost be mandatory.

 

[avz]

Hi guys and thanx for the replies. let me please share my thoughts with you. as per Krony's and Hi-tech's suggestion- apparently its a conventional way but isn't that a little bit odd to modulate the AV on the rf instead of connecting it directly to the point that is capable to interface with the signal? to my humble opinion what it thakes is only a break in the original circuit and a simple switch that will select between the two sources. as per mneary's reply - I wish I had the schematic diagram of it. I've searched the web and posted a request here on the forum, but to no avail. anyhow, it is quite an old Panasonic TC492EU (14" ?) tv set.
thanx again.

 

[kroni]

you could experiment a little with a signal generator or a protected source of video signal, and try to "inject" a video signal, where you think could be a possibility to insert the signals... but take care, crt's operate at around 25kV, and can even maintain its charge when being disconnected for days. a good strategy would be to use an "insulating transformer", to keep away from line potentials against ground.

good luck on your hunt, and stay on the safe side!

 

[mneary]

If you do this without the necessary skills or at least a well understood schematic, train a family member in CPR and keep a fire extinguisher handy.

 

[HiTech]

Precisely why I suggested that he simply buy or build an RF modulator and input A/V to it. No need then to remove the back cover and risk electrical shock.