An example of one fix is for the 9200T (9150T and 9300T are similar):
http://www.howtomendit.com/answers.php?id=424453
You have given very little information to help identify what the fault really is.
Humax make a number of different type of recorders in the UK: feeview, feeview with HD, and freesat.
Humax generally have the model number on the front of the unit.
For some of the models the ideal instructions to mend will also depend on the software as well. This is available via the system menu using the remote.
You do not say whether this has always happened or if it was like that from the start. If it was OK then was the box retuned at that point? Was a software update done when it started to go wrong? Was a software update done but the 'default setting' was not selected from the menus afterwards?
To identify the fixes it would also help to state whether there are any other issues as these may help to identify what the cause is and therefore what the fix should be.
NS, January 2012