Panasonic TR-5041P B/W 5" Portable - help

[demy1942]

I have this small tv and hooked it up to the converter box and then connecting to the external port using a 3.5mm plug attached to the coaxial cable. When I push the plug all the way in, doesn't really work, if I touch the outside of the port with the tip of the plug, it works better.

Any suggestion on making a stronger attachment to the back?
Other way to attach plug?
Different kind of plug?

Thanks for looking and great site, glad I found it

the plug works much better on my Casio 970