No clock on Humax PVR9200T?

I have a Humax PVR9200T which was working OK till the digital switchover. Had the freezing, but got over it. Now have a problem in that when I switch it to stand-by the clock doesn't come up - just 4 dashes. I have also noticed that when it is in this state you cannot record anything. I now have to leave the thing on all the time if I want to record. This is driving me crazy as my husband keeps switching it off when I go to bed and even if you switch it on again quickly, you still lose the recordings.
Can anyone help me please??