Malfunction on Panasonic DVD Recorder DMR-EZ48VEB?

By switching power to TV; a compatible Panasonic - Viera linked unit; I get a "Hello" message on Recorder followed by messages "U61" and "Self check did not complete. 1. Press OK. Then the unit opens the disc tray and turns to standby. 2. Press power to restart."

I carry out the instruction, but this last message still appears and the whole sequence, as described above, keeps on repeating itself each time. The unit will not respond to any other pressed function.

I should be grateful if anyone, familiar with the Recorder model in question, is able to help and assist in correcting the malfunction described. Many thanks.