I'll guess we'll just have to talk to each other

The TV's on the blink.  It's been like this for a couple of days now.

The TV is connected to a DVD recorder, so the signal comes from the aerial, through the DVD and into the TV.  We can still watch programmes we've recorded.  We can also watch anything we've down loaded.  What we can't seem to watch is broadcast TV.  Like we did in the olden days.  

I've done all the things it asks me to do to rectify the problem.  Unplugged everything - plugged it all back in again. Nothing.  I've plugged the TV directly into the aerial.  Again, nothing.  I've even shooed a wood pigeon off the aerial.

I talk to a man in the TV shop.  He tells me to do all things I've just done (he didn't mention wood pigeons, though).  He gives me a number to ring.  "You'll need to have the TV turned when you phone so they can talk you through it"

I get ready to make the call and switch on.   And then as if by magic - it works again.  After four days, the blue screen has gone.

OK Steveng - any ideas?