Hotpoint FFA60 frost free fridge

Question

Hotpoint FFA60 frost free fridge freezer approx 4 years old. Fridge seems fine but freezer is only just about keeping stuff frozen and is not cold enough to freeze fresh stuff properly. There is a small adjusting control to turn that should adjust temperature but this makes no difference. I have had a look inside and it looks if the dial is moving on the circuit panel and all the conexions look ok. Any clues? can I just get a new set of electrics or am I better of scrapping it?