SVR-HDT500 no signal/invalid format

[rebellion15]

I have an svr-hdt500 freeview recorder had it for about 2 weeks. Watched about 3 hours of recordings/tv last night then suddenly the screen went black and a message appeared no signal / invalid format and now when i turn the box on it stays on for between 5 and 10 seconds then i get the no signal message again then after about 20 seconds the pictures returns and it all happens again.. while the picture is there i can change channel and have managed to check signal strength which is about 60% and quality at 100%. Any ideas

[SPARTAKEV]

I'm having the same problem. Had the box for just under a yera, and has been working perfectly. But for the last couple of weeks, when I turn it on I get a blank screen and the invalid format message. I have found that switching off at the mains for a while helps sometimes, but not always, but is driving me mad and is virtually unusable. Help!