['LIVEWIRE?']

The fault WAS in the Tuner Box, but it was partly MY fault. I had removed the pulleys and tension spring associated with the tuning drive in order to check components obstructed by them, and, when reassembling the drive had set it incorrectly. Having reset the cores earlier today, the radio now receives all usual stations between 88 & 103 + Mhz at good strength on it's internal aerial(The manual says 87.5 to 100), so I've gained about 3Mhz{should say Mc/s with these old sets!} somehow, but will leave that as it is. All is now fine, the one remaining puzzle being the almost constant crackling until the set has thoughroughly warmed up(abt. 10 minutes) This is barely audible on station, though.