My Hyundai DVD player plays DVD's in Black and White or in a greenish tinit. Freeview, videos all okay. Any ideas?

It sounds like you are using a bad mixture of older technology. So you have;

A 24" (tiny) Sharp television with built in DVD Player.
A Freeview Decoder.
A Digital Box of some sort.

Freeview has a list of approved products

https://freeviewnz.tv/get-freeview/approved-products/

..

My DVD player only plays in black and white - TOSHIBA FORUMS

forums.toshiba.com/.../My-DVD-player...plays-in-black-and-white/.../47...

39L1350U) and am trying to hook up the DVD player. ... My DVD player only plays in black and white ... My DVD player is an old Sony. .... Was using and S-Video connecting cable to the TV. ... suggested to use VIDEO instead of COLOR STREAM, I changed that in the TV menu, plug the red and while at the back of TV where ...

No Color When My DVD Player Is Hooked Up - Community ...

community.insigniaproducts.com/...DVD-Players/...Color...My-DVD-Pla...

Jul 14, 2014 - I hooked up my DVD player and I have no color. ... you need to use the connections on the left side of the TV or on connections on the back. .... is turned on, which can cause this black and white image issue you're having. ... If the Player shows correctly on a different TV with the same hook up, and different ...

The picture from a disc player displays on the TV in black ...

some Blu-Ray Players have to be reprogramed through the telephone line look in manel

Consult the owner manual for the player (and or try it on another set) as many players have settings that can cause B&W or a single color display for the image.

my dvd player only plays movies back in black and white...not color. why?

Check the av channel on the tv,the av is normaly av2,if it say`s any different then press the av button on the tv r/c until it plays in colour

there is a circuit in the color section to put the tv to black and white if the color subcarrier is missing from the broadcast signal.
it is called a color killer and needs to be adjusted.
it is for a technician to do.
it operates off the 3.58mhz color subcarrier.

Check if the tv has different types of AV settings, as this affects whether the wii plays in black and white or colour.

try removing ac power and plug in power again sometimes helps

sounds like the video processors on the input are bad