Grundig 2012 intermittent volume.

[pilot mariner]

In post 6 I think I was jumping to conclusions too readily in condemning the EC92, the scanner signal seems constant (but reduced) when pulling valves further down the chain. The fault seems only to occur when all valves are fitted. Maybe the scanner idea is not such a good one after all, as it picks up radiation from the whole IF chain, not just the tuner box as proved above.

Mark