Philco Tropic 39-770EZ - Printable Version
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RE: Philco Tropic 39-770EZ - Ron Ramirez - 02-02-2015
Forgot to mention:
I also removed two of the original electrolytic cans today. The third was missing; I have an old electrolytic I can use to replace it with. All three will be restuffed with new electrolytics.
And both IF transformers were also removed today.
I took lots of notes as well. This is going to be a difficult restoration.
RE: Philco Tropic 39-770EZ - Ron Ramirez - 02-02-2015
The mystery of the golden tube sockets has been solved!
I looked them up in the 1941 Philco parts catalog. Those sockets, according to that catalog, have "special moisture-proof insulation".
Well, moisture-proof or not, they are still crap.
I've decided not to try and open up the audio output transformer. It was covered with high temperature wax. Baking it in my old toaster oven did not melt it; but only softened it a bit. I've pulled the transformer from the mounting frame. The 46-1226 output transformer will fit perfectly in the frame.
The wax was likely applied in an attempt to moisture-proof the transformer. But as we know from dealing with Philco coils, the wax usually trapped moisture inside rather than keeping it out. So the wax was probably a contributing factor in the transformer's failure.
RE: Philco Tropic 39-770EZ - Arran - 02-03-2015
Ron;
I have similar problems with the octal sockets used in many Electrohome built sets of the 1940s, but with those the phenolic can take the heat well enough, it's the tie points that like to snap off when you look at them the wrong way. So I am going to be replacing these cheap wafer sockets with some surplus Iron Curtain octal sockets, so these Electrohome sets will have some MIL spec Marxist interlopers installed in their holes.
Regards
Arran
RE: Philco Tropic 39-770EZ - Ron Ramirez - 02-03-2015
It's time to get radical.
[Image: http://www.philcoradio.com/images/phorum/39-770/39770-15.jpg]
As you can see, I went in and removed nearly everything from the IF amp through the audio outputs. I think it will be easier this way. It has to be rewired anyway due to the dried-out, nasty rubber-covered wires.
Arran, I was able to remove everything from the other tube sockets in this area which I want to keep without any other contacts breaking or otherwise coming off from heat. I found that it was easier to remove wiring from contacts when I had a tube plugged into the socket I wanted to keep.
So...as it looks right now, I will only have to replace the 6H6G (2nd detector) and the two 6F6G (audio output) sockets. I'm hoping I can save the det-osc, rectifier, and tuning light tube sockets as well. We shall see. But since I've completely stripped this area, I will concentrate on it first.
RE: Philco Tropic 39-770EZ - sam - 02-03-2015
WOW ron
you go for them really bad ones
I only do 1 wire at a time
I kneel down to you as you are the master
would like to see the trans have not seen one covered in wax yet
RE: Philco Tropic 39-770EZ - Ron Ramirez - 02-03-2015
I appreciate what you are saying, Sam, I really do; but do not kneel down to me, kneel only to God. He is the Master of masters.
I can take a photo of the transformer, but much of the wax has already been removed so I could remove the mounting frame from the core.
RE: Philco Tropic 39-770EZ - Ron Ramirez - 02-03-2015
Okay!
I have replaced five tube sockets.
I have added tube shield bases where this set originally had them.
[Image: http://www.philcoradio.com/images/phorum/39-770/39770-16.jpg]
As I mentioned previously, I like these 1937 tube shield bases much better as they allow you to use any type of tube you wish.
Under-chassis view:
[Image: http://www.philcoradio.com/images/phorum/39-770/39770-17.jpg]
I replaced the IF tube socket for one reason: I wanted to be able to ground pin 1 (metal shell) in case a metal tube ever gets used there. The original socket had no contact at pin 1.
Now comes the fun of rewiring, then installing new resistors and capacitors.
RE: Philco Tropic 39-770EZ - Ron Ramirez - 02-03-2015
For Sam:
Pictures of the original audio output transformer.
[Image: http://www.philcoradio.com/images/phorum/39-770/39770-18.jpg]
[Image: http://www.philcoradio.com/images/phorum/39-770/39770-19.jpg]
Roughly half of the wax has been removed here, and as you can see, the mounting shell has been removed, cleaned, and repainted as the top of the transformer was very rusty.
If you can imagine all of this together, and with twice as much wax over the windings and over part of the mounting shell...that is how it looked when I pulled it from the radio.
RE: Philco Tropic 39-770EZ - KCMike - 02-03-2015
Following along with your restore. Man lot of work on this one. You will win in the end.
RE: Philco Tropic 39-770EZ - Ron Ramirez - 02-04-2015
Let's make the 46-1226 transformer fit the 39-770 frame.
[Image: http://www.philcoradio.com/images/phorum/39-770/39770-20.jpg]
Here is the 46-1226 transformer (left). Its core will be removed from its original mounting frame and installed into the 39-770 mounting frame.
[Image: http://www.philcoradio.com/images/phorum/39-770/39770-21.jpg]
I unsoldered the grounded lead of the audio output secondary from the frame.
Then, I unfolded the "ears" on the bottom which holds the frame in place, and then pried the frame open enough so that the core could be removed. Next, the core was turned sideways to fit in the 39-770 frame, the bottom piece was put in place, and its mounting "ears" were folded back over.
[Image: http://www.philcoradio.com/images/phorum/39-770/39770-22.jpg]
Voila! The core of the 46-1226 transformer is now in the 39-770 frame.
Another view:
[Image: http://www.philcoradio.com/images/phorum/39-770/39770-23.jpg]
I will have to extend the length of the wires by adding wire to each lead. I'll do that later.
RE: Philco Tropic 39-770EZ - Chuck Schwark - 02-04-2015
RE: Philco Tropic 39-770EZ - Ron Ramirez - 02-04-2015
Now, let the rewiring begin:
[Image: http://www.philcoradio.com/images/phorum/39-770/39770-24.jpg]
I have attached filament leads (the new red wires visible in the photo above) to one side of each tube socket, from the 6K7G RF amp through to each of the 6F6G audio output tubes.
One side of the filament line is grounded in this set, so I will get to those later in the process.
RE: Philco Tropic 39-770EZ - Ron Ramirez - 02-04-2015
...a little more rewiring...
[Image: http://www.philcoradio.com/images/phorum/39-770/39770-25.jpg]
I've replaced all of the wires on bandswitch wafer "P". That wasn't easy!
The good news is that I'm nearly ready to start installing new components on the left side.
RE: Philco Tropic 39-770EZ - Arran - 02-05-2015
(02-03-2015, 12:16 PM)Ron Ramirez Wrote: It's time to get radical.
[Image: http://i326.photobucket.com/albums/k420/mrphilco/39-770%20Tropic/39770-15.jpg~original]
As you can see, I went in and removed nearly everything from the IF amp through the audio outputs. I think it will be easier this way. It has to be rewired anyway due to the dried-out, nasty rubber-covered wires.
Arran, I was able to remove everything from the other tube sockets in this area which I want to keep without any other contacts breaking or otherwise coming off from heat. I found that it was easier to remove wiring from contacts when I had a tube plugged into the socket I wanted to keep.
So...as it looks right now, I will only have to replace the 6H6G (2nd detector) and the two 6F6G (audio output) sockets. I'm hoping I can save the det-osc, rectifier, and tuning light tube sockets as well. We shall see. But since I've completely stripped this area, I will concentrate on it first.
Ron;
I will have to keep that trick in mind with regard to octal sockets in Philco sets from that era, but with Electrohome sets it would not help, the terminals have a habit of snapping off right at the slots where they slip between the layers of phenolic. For whatever reason the manufacturer of the octal wafer sockets used in Electrohome sets decided it would be a great idea to stamp a 1/16'' knotch in each edge of a 1/4 inch terminal leaving a weak spot in the brass where it goes between the phenolic, stupid, stupid, stupid. Philco must have used some sort of fixture to prevent the contacts from being torn out of the socket of these gold socket, that or the material was much more resilient when new.
Regards
Arran
RE: Philco Tropic 39-770EZ - Ron Ramirez - 02-05-2015
Well, Arran, when these sets were new, all Philco cared about was getting the thing assembled. They were not concerned with the poor repairman who would have to work on these cheaply made sets down the road.
And yes, from 1939 (mid-1938 ) on, Philco's products became noticeably more cheaply made. Actually, I think the cheapening began in 1937 (mid-1936), with the introduction of those awful RF units; became more pronounced in the 1938 season; and definitely so from the 1939 season onward. It was in the 1939 season that these crappy golden yellow sockets first appeared. Plus rubber-covered wires, which I would guess were probably cheaper than the cloth-covered wires?
I am guessing the same was probably true of Electrohome. Once the bean counters take control, quality goes out the window.