Panasonic recorder dvd - no picture on screen?

We have only our dvd and video working, no tv aerial, but are enjoying watching dvds and videos. It has been working great, but suddenly, only the video is working. There is nothing wrong with the Panasonic recorder which is a nearly new one and had little use. It played beautifully a couple of days ago and today, try as I might no picture, just a blue screen, but it is tracking along so is definitely working.

It is a Panasonic dvd recorder Model No. DMR - Eh50. Thankyou.