The PHILCO Phorum
40-180 tube information - Printable Version

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40-180 tube information - mountain man - 02-21-2014

have a 40-180 and the tubes that are in it in some cases do not match the schematic det osc on schematic is 7j7 tube in chassis is cj8g can't find out if thats a sub or not, any suggestiions?

RE: 40-180 tube information - morzh - 02-21-2014

Did you mean 6J8G - this is an octal version of the same tube.

RE: 40-180 tube information - DeckApe - 02-21-2014

The 6J8G is a production modification for the 40-180 (presumably there was a shortage of 7J7 tubes). I believe the connections are slightly different under the chassis owing to a different pin configuration, so draw a picture as to what connects where before you start on that socket.

This information and much more is available from Chuck Schwark and his Philco information service... As a customer, I can tell you it's well worth the $7 to have all the Philco-released info in your hands before you start. Icon_thumbup

RE: 40-180 tube information - murf - 02-21-2014

I'll have to watch this thread.
I will be working on a 40-190 chassis next week. Same chassis other than the added tube on the 190.
Mine has the 6J8 tube in it.
murf

RE: 40-180 tube information - morzh - 02-21-2014

Things being equal I prefer octals to loctals - the oxidation on loctals is a common thing and cleaning it is a b...ch.

RE: 40-180 tube information - Joeztech - 02-25-2014

I agree with Morzh. Octal tubes fit firmly enough in their sockets, but the loctal types are real bears sometimes to remove depending on available space nearby for finger access and maneuvering. When I first encountered the 7xn tube types many years ago I first expected them to have a 7 volt filament until I looked one up in a tube manual and saw that they used 6.3VAC or DC just like many other tubes. Making a sketch of connections to a tube socket before disconnecting anything can be a big help. Alternatively, if you can take a good resolution well focused picture of the area with a digital camera that will suffice too. Be sure to note the orientation of the key-way or indexing key of the tube socket. I find octal tubes much easier to count the pins from the key than loctal types. Loctal sockets are very difficult to determine the position of the key from under the chassis by comparison to octal types.

Joe