DISCLAIMER: Please DO NOT perform this modification unless you have adequate experience working on electronics. CRTs can be very dangerous if you do not know what you are doing. I am also not responsible for any damage you may do to your television while attempting this mod.
Here’s a quick tutorial of how I was able to add RCA AV inputs to my Bentley portable television. I also installed an internal AC-DC12V power supply in the battery compartment so that it can be plugged directly into the wall.
To open the television, go ahead and remove the two black screws on each side near the face, and the screws inside the battery compartment. You should then be able to lift the top cover off. Once inside the television turn your attention to the small audio board. We will tap into this board for our audio input. I recommend adding a good length of wire to the input point and then cutting it down at the end when you’re ready to attach them to your RCA jacks.
After you finish modding the sound board you can move on to the composite video mod. The connections we have to make are on the bottom of the board. You will need to remove all the screws holding the board down and also the two screws holding the face of the television down on each side. The board and TV face should pull out together.
Now that you have the composite video input done you can re-install the board into the body. Don’t forget to attach the little side plate that goes over the adjustment knob and external antenna jack before screwing the board down–otherwise you won’t be able to get it on. Now you will have to figure out how you’re going to route your wires to your RCA jacks. I cut a slot in the battery compartment and ran the wires through to the back. You may decide to do it another way.
When you are wiring your RCA jacks make sure to add a 75ohm resistor on the video input. The picture will be too bright if you don’t add it. You can either run the resistor in-line with the input wire, or attach it straight to ground on the jack like I did. I chose to ground my RCA jacks to the shielded box pictured on the right.
After you’ve completed the modifications, your Bentley portable TV will now have its tuner disabled and will essentially be a monitor. You can add a switch to break the ground of the two pins to re-enable the tuner, but in this day and age I don’t see the point in doing that. Enjoy!