There is a complete KN6500 display module available Here :

http://www.ebay.co.uk/itm/LCD-Display-Assembly-Panel-Fr-Technics-KN6500-KN-6500-Music-Keyboard-Synthesizer-/331102260937?hash=item4d173b8ec9:g:kbUAAOxyUrZSy79u

This is the UK eBay website but I can see the same item on the US eBay website...

http://www.ebay.com/itm/LCD-Display-Assembly-Panel-Fr-Technics-KN6500-KN-6500-Music-Keyboard-Synthesizer-/331102260937?hash=item4d173b8ec9:g:kbUAAOxyUrZSy79u

The item is in the US... Bit Pricy.....

I believe the KN7000 was the first to add a Video Output connection, and it doesn't produce very good results... See thread ref. KN7000 faulty screen....