[EdHolland]

Well something isn't right, there's a lot of crackling, particularly on AM, but it seems also to affect FM to an extent. It is most noticable when tuned into a station, and only just discernable when tuned to a quiet spot. It sounds like the descriptions I have read of silver mica disease - static crashes - and it seems to get worse as the set is run for longer periods.

I'll have to pull one of the IF cans and take a look. Meanwhile I'm thinking about the best way to track down which of the transformers is causing the problem, presuming for the moment that it is just one of them misbehaving - I'd like to get that one first, just to be sure I'm on the right track, and to minimise the risk of causing damage.

One thought is to inject 455 kHz starting at the detector and then working back up the IF chain. If necessary, the upstream stages could be disconnected to prevent noise coming through.

Any thoughts from the experts would be welcome at this point - this is not something I've encountered previously.