Remove the attenuator. Most modern equipment does not need them. Try rescanning for new channels. It could be the power supply going faulty. This is the most common cause of Thomson freeview box problems (about 90%). They are on Ebay for between £10 - £25. Or take it to a tv engineer for testing/repair. Have you had your aerial checked to see if its suitable for digital? The new aerials are wide band more suitable for the digital frequencies used.
thomson fan
June 2012