02-02-2015, 06:57 PM
The beginnings of a long, slow process...
[Image: http://www.philcoradio.com/images/phorum...770-09.jpg]
Here you see the 6K7G RF tube socket which is about to be replaced with a genuine Philco tube socket - brown phenolic, not the goldish-yellow crappy socket which, unfortunately, this set is full of.
[Image: http://www.philcoradio.com/images/phorum...770-10.jpg]
Zoomed out a bit, to show the 6J8G socket to the left of the 6K7G socket. As you can see, the 6J8G is the crappy yellow type.
[Image: http://www.philcoradio.com/images/phorum...770-11.jpg]
After unsoldering some wires, the ill-fitting socket was removed...
[Image: http://www.philcoradio.com/images/phorum...770-12.jpg]
Here is the replacement socket - a used Philco socket pulled from a dead chassis. To the left is a 1937 Philco tube shield base. Philco should have kept using these after 1937. But instead, beginning in the 1938 season, Philco went back to the 1936 style tube shield base - to prevent anything but the use of ST style tubes. Only the ST tubes (the "G" types) will fit through the hole in the bases used from 1938-1942. With the 1937 style tube shield bases, one may use any tube he or she wishes - ST (G), GT, and (shudder!) metal.
I am using a 1937 style shield base for two reasons: one, for the versatility as mentioned above; and two, these are the only shield bases I have on hand.
[Image: http://www.philcoradio.com/images/phorum...770-13.jpg]
A look at the newly replaced socket from the top of the chassis, with the 1937 type shield base in place.
[Image: http://www.philcoradio.com/images/phorum...770-14.jpg]
...and how it looks from under the chassis.
-----
I removed the audio output transformer today. Did I mention that I hate those crappy yellow tube sockets Philco sometimes used? A tube socket contact came off each of the two 6F6G sockets when I attempted to unsolder the audio transformer leads. So there are two more sockets I will have to replace in addition to the cracked 6H6G socket and probably the 6K7G IF tube socket.
I will not be surprised if I end up replacing all eleven of them, but I hope I don't have to go that far. These sockets are so fragile...it is so easy to ruin one, even when using a low-wattage soldering iron instead of the flamethrower Weller D550. The brown wafer sockets are much tougher...I really wonder why Philco used the yellow sockets...I used to think that perhaps this was some sort of low-loss material because I normally only see these used for the det-osc tube. But as I said earlier, this 39-770 has eleven of them.
Well, I should say had eleven of them...now it has ten.
[Image: http://www.philcoradio.com/images/phorum...770-09.jpg]
Here you see the 6K7G RF tube socket which is about to be replaced with a genuine Philco tube socket - brown phenolic, not the goldish-yellow crappy socket which, unfortunately, this set is full of.
[Image: http://www.philcoradio.com/images/phorum...770-10.jpg]
Zoomed out a bit, to show the 6J8G socket to the left of the 6K7G socket. As you can see, the 6J8G is the crappy yellow type.
[Image: http://www.philcoradio.com/images/phorum...770-11.jpg]
After unsoldering some wires, the ill-fitting socket was removed...
[Image: http://www.philcoradio.com/images/phorum...770-12.jpg]
Here is the replacement socket - a used Philco socket pulled from a dead chassis. To the left is a 1937 Philco tube shield base. Philco should have kept using these after 1937. But instead, beginning in the 1938 season, Philco went back to the 1936 style tube shield base - to prevent anything but the use of ST style tubes. Only the ST tubes (the "G" types) will fit through the hole in the bases used from 1938-1942. With the 1937 style tube shield bases, one may use any tube he or she wishes - ST (G), GT, and (shudder!) metal.
I am using a 1937 style shield base for two reasons: one, for the versatility as mentioned above; and two, these are the only shield bases I have on hand.
[Image: http://www.philcoradio.com/images/phorum...770-13.jpg]
A look at the newly replaced socket from the top of the chassis, with the 1937 type shield base in place.
[Image: http://www.philcoradio.com/images/phorum...770-14.jpg]
...and how it looks from under the chassis.
-----
I removed the audio output transformer today. Did I mention that I hate those crappy yellow tube sockets Philco sometimes used? A tube socket contact came off each of the two 6F6G sockets when I attempted to unsolder the audio transformer leads. So there are two more sockets I will have to replace in addition to the cracked 6H6G socket and probably the 6K7G IF tube socket.
I will not be surprised if I end up replacing all eleven of them, but I hope I don't have to go that far. These sockets are so fragile...it is so easy to ruin one, even when using a low-wattage soldering iron instead of the flamethrower Weller D550. The brown wafer sockets are much tougher...I really wonder why Philco used the yellow sockets...I used to think that perhaps this was some sort of low-loss material because I normally only see these used for the det-osc tube. But as I said earlier, this 39-770 has eleven of them.
Well, I should say had eleven of them...now it has ten.
--
Ron Ramirez
Ferdinand IN
