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Boater Sam · 5th Dec 2017, 1:37 am

L18 has nothing to do with the 4v heater supply to the UU6, it is the smoothing choke on the HT.

I am confused as to why you have no heater voltage on the underside of the valve socket at pins 1 and 8 yet the transformer has the correct voltage.
Either you selected the wrong pins or the wire/s between the transformer and the socket are open circuit.
I would suggest that it is likely that it is the valve socket failing to make contact with the heater pins. Inspect the actual metal sockets in the holder, they may be broken or have no spring left. Try gently closing them up. If as a last resort you have to change the socket, it is a Mazda-Octal socket not an Octal, a bit harder to find. Depending on the type of socket fitted you should be able to pinch one or more of the 4 or 5 unused contacts from the socket and refit them in place of the duff ones. Straighten the solder tag underneath and they should push up and out.
Great work saving that valve, how is the 6P25 original?
Its really good to hear that the set is working.

5th Dec 2017, 1:37 am	#44
Boater Sam Banned Join Date: Dec 2013 Location: Middlewich, Cheshire, UK. & Winter in the Philippines. Posts: 3,897	Re: Murphy A188C repair. L18 has nothing to do with the 4v heater supply to the UU6, it is the smoothing choke on the HT. I am confused as to why you have no heater voltage on the underside of the valve socket at pins 1 and 8 yet the transformer has the correct voltage. Either you selected the wrong pins or the wire/s between the transformer and the socket are open circuit. I would suggest that it is likely that it is the valve socket failing to make contact with the heater pins. Inspect the actual metal sockets in the holder, they may be broken or have no spring left. Try gently closing them up. If as a last resort you have to change the socket, it is a Mazda-Octal socket not an Octal, a bit harder to find. Depending on the type of socket fitted you should be able to pinch one or more of the 4 or 5 unused contacts from the socket and refit them in place of the duff ones. Straighten the solder tag underneath and they should push up and out. Great work saving that valve, how is the 6P25 original? Its really good to hear that the set is working.