Rebuilding a Philco Tropic 42-730EZ - Printable Version
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Rebuilding a Philco Tropic 42-730EZ - Ron Ramirez - 10-12-2014
Well, I'm off and running on another radio project. This time, I am going to recap, rewire and recarb a Philco-Tropic 42-730EZ.
[Image: http://philcoradio.com/images/phorum/tropics/1942/42-730T-1.jpg]
Photo courtesy Eddie Haines. I now own this very radio.
You can learn more about the 42-730 here:
http://www.philcoradio.com/gallery2/1942a/#Model_42-730T
http://www.philcoradio.com/phorum/showthread.php?tid=15028 (scroll down to Model 42-730T)
Like most of my Tropic sets, this one has been sitting around for a few years patiently waiting for me to get around to doing something with it.
Here's how the chassis looks outside of the cabinet:
[Image: http://www.philcoradio.com/images/phorum/42-730EZ/Image00007.jpg]
It uses seven tubes and has five tuning bands - the standard AM band (540 to 1720 kc); SW from 2.3 to 7.5 and 7 to 22 mc; a fourth band covering the 31 and 25 meter bands (9.4 to 12 mc), and a fifth band covering the 19 and 16 meter bands (15 to 18 mc).
As usual, I started working on it before I remembered to take a "before" under-chassis shot.
[Image: http://www.philcoradio.com/images/phorum/42-730EZ/Image00006.jpg]
At this point, I have replaced three paper capacitors and four resistors, and also replaced a few rubber-covered wires. Can you tell which capacitors have been replaced?
You can follow along by looking at the schematic here (warning for those of you with slow connections: this file is 633K in size!).
RE: Rebuilding a Philco Tropic 42-730EZ - Ron Ramirez - 10-12-2014
I made the decision when beginning work on this set that I would go to the added trouble of restuffing the original paper capacitors if possible.
Look at the surprise I found when I removed the innards of the first one:
[Image: http://www.philcoradio.com/images/phorum/42-730EZ/Image00001.jpg]
[Image: http://www.philcoradio.com/images/phorum/42-730EZ/Image00005.jpg]
Philco actually stuffed a Cornell-Dubilier Tiger inside a Philco branded sleeve! Notice also how Philco rated this cap at 200 WVDC but the Tiger inside is actually rated at 400 WVDC.
It received a new yellow film cap rated at 630 WVDC.
[Image: http://www.philcoradio.com/images/phorum/42-730EZ/Image00004.jpg]
I sealed each end with hot glue, let it set up, and then reinstalled the new cap in the radio.
I also pulled the old paper cap out of the original C-D sleeve; I may need that sleeve for restuffing later on.
RE: Rebuilding a Philco Tropic 42-730EZ - morzh - 10-12-2014
Ron,
Unless you tell me that you know for a fact that Philco rolled their own caps, I would theorize all their Philm (that is paper) caps were rebranded.
It is cheaper to buy in qty from a component manufacturer than to make your own.
As for can I tell...? the angle of the photo is such that I cannot see the ends. Otherwise I could try
RE: Rebuilding a Philco Tropic 42-730EZ - Ron Ramirez - 10-12-2014
The three largest caps in the middle of the chassis are the ones that have been restuffed (so far). Unlike the two black .05 uF caps, the 0.2 uF cap only had the actual part inside the outer sleeve - not another manufacturer's sleeve. (Although it was probably made by another manufacturer, please read on...)
And, yes, Mike...at one time, Philco did make their own capacitors. All of the caps inside those bakelite blocks that everyone loves to hate were all made by Philco. But after a 1938 strike, Philco began purchasing more and more parts from outside suppliers. You can read about it in the second to last paragraph on this page:
http://www.philcoradio.com/phorum/showthread.php?tid=15057
RE: Rebuilding a Philco Tropic 42-730EZ - klondike98 - 10-12-2014
So...did you stuff the Tiger first and then stuff that into the Philco sleeve?
Lookin' good.
RE: Rebuilding a Philco Tropic 42-730EZ - morzh - 10-12-2014
SO, 111 was the first Philco superhet....glad I got it.
RE: Rebuilding a Philco Tropic 42-730EZ - Ron Ramirez - 10-12-2014
(10-12-2014, 07:03 PM)klondike98 Wrote: So...did you stuff the Tiger first and then stuff that into the Philco sleeve?
Nope...
[Image: http://www.philcoradio.com/images/phorum/42-730EZ/Image00004.jpg]
I only used the Philco outer sleeve. I did save the Tiger sleeve for possible future use.
And, by the way, thanks!
RE: Rebuilding a Philco Tropic 42-730EZ - Ron Ramirez - 10-13-2014
Today's progress:
[Image: http://www.philcoradio.com/images/phorum/42-730EZ/Image00001-1.jpg]
I have replaced some more wires and a few more resistors. I have also replaced a couple mica caps and one more paper cap, with several to go.
Both IF transformers have now been removed so that they may receive new wires.
RE: Rebuilding a Philco Tropic 42-730EZ - Arran - 10-13-2014
Ron;
I have a trick I came up with for restuffing tubular paper caps, I like to hot glue a strip of corrugated cardboard around the outside of the new poly film cap and wedge it in place inside the old cardboard tube, it centers the leads and cuts down on how much hot glue you need to fill the ends. As for finding another brand of capacitor inside a Philco unit, I found that inside the large bypass cap in my Canadian model 78 (46-1201) set, the one with the RF choke mounted on the outside, it too was a Cornell Dubilier brand capacitor, which shows that Philco chose wisely in terms of outside suppliers, Rogers also liked to use Cornell Dubilier brand caps, which may explain why many still have most if not all of the same caps they left the factory with. Another good make of the time was those Solar Sealedtites, with Aerovox somewhere between, but regardless of who made them I would not trust a 60+ year old paper capacitor.
Regards
Arran
RE: Rebuilding a Philco Tropic 42-730EZ - morzh - 10-14-2014
I do a similar thing, I wrap a piece of paper or cardboard around leads and push it inside, then pot with hot glue.
RE: Rebuilding a Philco Tropic 42-730EZ - klondike98 - 10-14-2014
Arran & Mike...thanks for that tip! I've always had trouble keeping the new cap centered without dripping hot glue all over my fingers.
RE: Rebuilding a Philco Tropic 42-730EZ - thirtiesradio - 10-14-2014
Very nice job Ron.
What is the best way to remove the insides from the original tubular paper caps for restuffing?
RE: Rebuilding a Philco Tropic 42-730EZ - Ron Ramirez - 10-14-2014
I'm using my hot air gun to melt the wax and then, carefully holding the body of the cap with a double thickness of paper towel, pulling the insides out with needle nose pliers while the thing is still hot.
I would also like to thank Arran and Mike (morzh) for the tips, good stuff (no pun intended) to know.
RE: Rebuilding a Philco Tropic 42-730EZ - klondike98 - 10-14-2014
Don't know if it's the best way but I hold one lead with pliers, heat the cap with a hair dryer, then pull the other lead with another set of pliers. This "usually" causes one end of the cap's wax plug to pull out. Then I'll hold the cap in a gloved hand and push the cap guts out with a small screw driver. Sometimes I have to chip out some of the remaining wax with a knife blade before pushing out the guts. Then I clean off the outside of the cap with mineral spirits. Key is to get it hot enough to soften the wax. It seems some caps have higher melting point wax than others.
RE: Rebuilding a Philco Tropic 42-730EZ - thirtiesradio - 10-14-2014
Thank you both for the replies
