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City: Sneedville, TN
I have been continuing work on the radio slowly but surely. I noticed that the 3 wires in the speaker harness were becoming frayed and worse for wear, bare in fact in one place from handling and moving around as I have worked on the chassis, so I replaced them I had suitable white, green, and green with white tracer wire hanging around, albeit with plastic rather than cloth insulation, but I wound up a harness of it and replaced the 3 original wires of the speaker harness. I have also begun to replace parts on the terminal strip side of the chassis I checked all the resistors, and have found they are all within 10%, well better than their 20%
ratings, so I left them. I replaced the 2 paper condensers, and one grid cap wire, and that was all I needed to do.
[Image: http://41.media.tumblr.com/547163d6adec2...1_1280.jpg]
[Image: http://40.media.tumblr.com/15c2f993bf473...2_1280.jpg]
So, now I still have to buy some SPT2 18/2 and replace the power cord, re-install the tuning section, wire the speaker back up, and I can begin testing and see where I have screwed things up, LOL.
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I didn't like the look fo that plastic wire I had made the speaker harness from, so I ordered #20 cloth over plastic in white, and, with the help of some green acrylic paint, colored one wire green, and left white stripes on another, and the third all white, so they basically match the colors listed on the schematic. I then installed them. I also made a little piece of micarta board using inch and a half square pieces of calligraphy parchment and 2 part, 5 minute epoxy. It is easy enough. On a piece of scrap paper mix up the epoxy. Then on a piece of wax paper place a piece of parchment. spread epoxy on the top, and stack on another piece. Carefully press out any bubbles and spread again, and put on another piece of parchment. Keep stacking to the desired thickness, but don't spread epoxy on the last sheet. Let it dry well, overnight at least. I used this to make the insulator to rebuild the dial lamp. First I traced the lamp socket, and carefully nipped down the micarta until it was just outside the line. Then using the point of my Exacto knife, I drilled a little hole right in the center of the little circle, working from each side alternately, just big enough to slide through the conductor of the wire I was going to use. Once the wire was through I looped the end tightly and flat against the insulator, and soldered it into a little blob. this is how it came out.
[Image: http://41.media.tumblr.com/e9518bb565b39...1_1280.jpg]
so, I have progressed to the point where I can begin testing. First I connected the speaker back up. Then I tested things with only the dial lamp and 6 volt tubes installed. No explosions, no "hot" smells, and the light burned nicely. Next I installed the 5Y4G. No sound from the speaker. I look at the speaker and see one of the voice coil wires has come loose from the little connection for it at the bottom of the output transformer. I correct that, and try again. This time I have some hissing from the speaker, which changes in sound when I touch various grid caps, and rises and falls nicely with the volume control, and varies in tone with the tone control. It seems things in the amp are basically working. I have B+. Nothing is drastically wrong under there. Tomorrow I shall continue, but I am quite happy so far. Here are a couple more pics, one of the whole underside of the chassis as it stands now, and the other of the chassis and speaker on my bench turned on.
[Image: http://40.media.tumblr.com/8b950cb601923...2_1280.jpg]
[Image: http://40.media.tumblr.com/1115100c9d04e...3_1280.jpg]
I am still using the old dial until I get to the final stages of alignment. Don't want to crack or scratch the new one ! So, that's how it stands tonight, tune in again for further adventures...
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I couldn't keep away.... The news continues to improve. I set up my sig gen and frequency counter, and began to see where the signals were going. Right off to bat, with the output at 470 KC I heard the 1000 cycle tone coming through. I hardly had to adjust the IF stages to get a VERY good signal coming through with the 470 KC injected on the red antenna terminal. So, the IF stages are now set, and the audio stages seem to be working a treat. The tone control works fine, as does the volume control. no Rice Krispies. I tried to see if it would pick up 700 KC, but could not get it to, so I will continue tomorrow and see where things are going wrong.
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I couldn't sleep. It was just SOOOOO close I had to keep working. With the sig gen found that by injecting a 1000 KC signal at the 6A8 grid I was able to pick it up fine at 1470 on the dial. Hmmm, oscillator problems. I then rechecked the obvious and found that I had missed reconnecting the connections that come from under the chassis to the front section of the variable condenser frame. I reconnected that, and fired the radio up again. BINGO !! I was able to pick up about 7 fairly local stations on the AM band, and one station clearly on the shortwave band with no antenna at all connected, and in my basement ! The sound of the re-coned speaker is good, no distortions at all, but is crisper on the highs than the originals I think. All the controls work beautifully. Tomorrow I will check the alignment of the dial, but, having changed absolutely none of the frequency critical parts or adjustments in the tuning section, I am hoping it will be very close already. The AM band seems to be. So, with that little victory, I hope I can now manage to sleep. Tune in again for more of this adventure.
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State, Province, Country: OR
Posts: 1,824
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Joined: Jul 2014
City: Sneedville, TN
My signal generator crapped out on me before I could get farther with the alignment. It has been flakey above 2 MC for a while, and it finally just crapped out. Serves me right for buying cheap. I bought a better one and it arrived much faster than I expected so I continued with the final alignment. I found, as I expected, that everything was already in almost the perfect position, and only the slightest tweaking was needed to bring things up to their peak performance. Also, the frequencies were aligned well across the dial. I hoped for this, since I had not had to do anything to the mica caps or coils or other frequency critical components, and the radio itself seemed to be relatively unmolested, and was not disappointed. So now I have to be patient until Spring, since my house is too cold to do the cabinet work. Hmmmm.... Maybe I'll find a safe corner to stash the chassis, etc. from the 37-61, and get to work on the next 48-482.... or maybe the 37-665 I have my eye on, if I can buy it cheap enough to justify the high shipping cost... I am SUCH an addict ! I am quite fond of 37 Philcos though, one of my first Philcos was a 37 console, a 620 I believe, which I gave to a buddy's family when I went in the Navy.
(This post was last modified: 01-01-2016, 12:54 AM by mikethedruid.
Edit Reason: spelling
)
Posts: 1,824
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Joined: Jul 2014
City: Sneedville, TN
I have continued to tweak the alignment of the 37-61, and it is now dead on on both bands, and is surprisingly sensitive and selective. Even with only about 6 feet of wire attached to the antenna terminal, no ground, on the workbench in my cellar I am able to pick up WWV on both 10 MC and 15 MC, faint but clear, which speaks well for the set since WWV is kind of hard to pick up here because of a big hill just to my west. The AM band is excellent too. On the same antenna I am able to pick up both WOR 710 in New York, and 740 Zoomer radio out of Toronto, Canada, both of which I kind of use as a benchmark. I am now satisfied that the radio is performing about as well as it can. Now I just have to wait until the weather warms up and I can continue work on the cabinet, the adventure of which I am chronicling in the cabinet section.
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Good job Mike. Hang in there it will be warm before you know it. I have three cabinets waiting on warm weather as I have nowhere inside to spray.
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