I allready have an RF converter, PLL. LED display. But very big! Found this:
https://www.ebay.co.uk/itm/Mini-AV-R.../163877599951?
This is probably a small circuit board I could built into the TV itself.
Problem is that I have no idea of the quality of this item. I bought a TV modulator before, but it was a scam as the unit hade a "hobby ciruit inside" and lethal power supply... so maybe better to stay away?