Panasonic TH-65LFE7E shuts down after few seconds standby led blinks on a 5 second interval.

Hi
 
I am having trouble finding any information regarding this product.
 
The unit powers up and the output is displayed on the screen for between 0 and ten seconds, the unit then powers down, the red standby LED on the front of the unit blinks then remains off for 5 seconds then blinks again.
This cycle continues until the power is disconnected, if the power is reconnected the unit goes back in to stand by (red led steady) it will then power on again.
Also in the error mode (red led blinking) and the power button on the back of the unit is pressed twice it will power up but this does not happen if the remote is used.
 
I have tested various capacitors and diodes but all seems well, I have also replaced the power supply with a reconditioned unit but this has not helped.
I have been unable to obtain any service information for this product.
 
So any input would be most helpful.
 
Thank you
 
Stephen Fry