There a number of different causes that would result in this. Unfortunately you do not give very much information and therefore this cannot be narrowed further.
At what point does the Humax fail to record? Does it let you set timers?
Did it suddenly stop recording all together or just sometimes?
If it is just sometimes then are certain channels worse than others?
Can you still play old recordings?
While watching a recording live does pressing 'record' on the remote start a recording? If it does then is the recording playable afterwards?
Have any of your old recordings started disappearing from the record list?
Is there still a record option on the menu list?
Did the epg always fill up OK after a few hours?
What software version is it on? (To look this up: MENU > System > Status)?
Did the recording fault only start to occur after someone re-tuned it?
Do all the channels seam to appear in the correct order on the epg?
Do you have any duplicate channels?
When you manually retuned it did you do it in a way that you would only receive channels from one transmitter.
Can you think of any other possible symptoms?
Is there anything that you have posted that you could expand on to make it easier for others to understand what you are experiencing?
Anon
December 2011