The aerial circuit board must have developed a fault as stations have very bad reception. Have changed the aerial mast with another, problem persists, so that's why I think it's the circuit board, as when I stuck a 3 foot copper pipe touching the top of the mast, brilliant reception. So is there a longer aerial than the 12" mast which will screw in the base without the need to go to huge expenditure at Renault?

roger, November 2016

The radio is receiving a weak signal and the tuner is struggling accordingly. You have shown that the tuner is OK by using a giant aerial to capture a stronger signal - my guess - and it's only a guess - is that there's a problem with the aerial cable that goes between the aerial and the radio itself. I suspect that the shield braid is no longer connected at one end or the other.

When you applied the copper pipe you too were forming part of the aerial circuit - I doubt you will find a long aerial that will easily attach - I doubt that the radio has an internal fault - but you never know.

Amazon will sell you a car aerial for £5.35 post free but it will need to have a hole cut in the bodywork to fit it - RMA305

Good Luck..., November 2016