Picked this virtually new unit up from my mother last week. All working fine. But now no video. Sound is fine. It responds to the remote (well, I can change channels and hear the sound change so guess it is responding). Checked the SCART connection..seems plugged in OK. The guide mentions SOURCE possibly being set to the wrong one so toggled that a few times with the remote (what does Source do exactly?). So run out of ideas. Any suggestions welcome.