Murphy A674 intermittent LW reception.

[g4aaw pete]

I’ve been at odds with an annoying fault on a Murphy A674 for some time.
I did all the usual capacitor changes, switch cleaning and valve swapping as is the norm.
However, LW would intermittently disappear despite my various efforts.
During an idle moment this afternoon I peered at the circuit to see what I’d not tried yet.
Sure enough there it was. A phone jack with a pair of switch contacts labelled L.W.
The service data notes state:-

Swiss L.W. socket. This socket is provided so that the receiver can be used in certain areas of Switzerland
to receive special L.W. transmissions over telephone lines. To reduce interference, the internal ferrite rod
aerial is automatically disconnected from the L.W. aerial coil when the input jack plug is connected to this socket.

So there we are. I should have read the circuit notes. A squirt of Servisol through the jack hole was all that was needed!

Regards to all on this invaluable forum
Pete