The PHILCO Phorum
National NC-60-Special - Printable Version

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National NC-60-Special - mikethedruid - 11-10-2021

Back in October I bought this National NC-60-Special. It is a glorified All American 5 circuit, and a successor to the National SW-54. It was made to compete with the Hallicrafters S-38E. If you look at the circuit you will see the striking similarity, right down to the "gimmick" used to provide feedback in the IF stage. Here is the schematic, I pieced the two halves together since they are on two different pages in the manual...

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Here is what the radio looked like before I began any work...

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I have ordered a number of condensers for the radio, and will have to wait for them to arrive. Other than that I have begun work by removing the chassis, doing some cleaning of the topside, removing the tubes for testing, and replacing the speaker which was pretty bad. I happened to have one of the right size and resistance in stock, which made it easy...

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RE: National NC-60-Special - PhilcoMike - 11-11-2021

Man Mike it sure does look like they copied the Hallicrafters for sure.

Mike

RE: National NC-60-Special - mikethedruid - 11-11-2021

I continued to work on the NC-60-special. All the tubes tested good, which was a pleasant surprise. I spent a great deal of time loosening up the tuning condensers, both the main and bandspread, as well as both the dial slide mechanisms. This radio must have sat in a damp place for some years. It took a lot of working back and forth with my oil mixture on the bearing points of the condensers and sandpapering the slides and pointer slider insides, and lightly lubricating the slides. Finally have the tuning working nicely. I also replaced all the paper and ceramic disc condensers. I am waiting on 200 volt 40 MFD condensers to finish up the under chassis work, then there will only be the alignment.

Here is the underside of the chassis at the beginning of work. I had only removed the rivet holding the multi section "firecracker."
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This is after all the work so far. I'm just waiting for the 3 40 MFD 200 volt electrolytics to finish. They will go on the terminal strip on the right side.
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RE: National NC-60-Special - PhilcoMike - 11-12-2021

Nice work Mike!

RE: National NC-60-Special - tbone - 11-14-2021

I had one of these a few years ago, and I finally sold it. When I got it the CW didn’t work. I found the 12BA6 cathode resistor was 1.5K and not 150 ohms! It was original and left the factory that way. I liked listening to it and it wasn’t bad for an AA5!

RE: National NC-60-Special - mikethedruid - 11-15-2021

Playing with this NC-60 I was reminded of the Knight Kit Star Roamer I built many years ago, so I looked at the schematic...

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It really is a much better radio. As a kit, it cost less than the NC-60. No wonder it sold like hot cakes and was so popular in its day. How many of you built the Star Roamer when you were young? I already know several folks who did. I still have mine, actually my second. I gave my first to a friend, who came from England, back during the Falkland Islands War, so he could listen to the BBC. You could still get the kit in those days, although Radio Shack, which had bought out Allied, was closing them out. As I remember, the kit was on sale for $39.95.
Here's the NC-60 schematic again for comparison...
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RE: National NC-60-Special - Eliot Ness - 11-15-2021

My older brother gave me a Star Roamer kit for Christmas when I was young. I guess that was my first kit build, but at some point many years later I sold it. Having regretted doing that in later years I bought another one on my last trip to the Estes auction.

462ron - 462ron - 11-15-2021

Mike, yes sir, built the Star Roamer probably 50 years ago and still have it. I remember there being a lot more to listen to back then. I dug it out about 5 years ago and tried it and it had the expected hum so I installed a terminal strip and mounted the 3 or 4 electrolytics on it and gave it a quick alignment since I didn’t have the signal generator or knowledge to do it way back then. Today I use my Zenith TO mostly!

Ron

RE: National NC-60-Special - Radioroslyn - 11-15-2021

I built one in '67 or '68. It was not so great. Liked my BC-454 a whole lot better.

RE: National NC-60-Special - mikethedruid - 11-15-2021

If all you were interested in hearing lay between 3 MC and 6 MC, then I'm sure the BC-454, being a military surplus receiver was quite good, especially since it had 6 tubes and an RF stage before the mixer oscillator, and 2 IF stages. What did you do about the power supply?
     As for the Star Roamer, it is a 5 band, general coverage receiver with longwave from 200 kc to 400 kc, BCB from 550 kc to 1800 kc, and shortwave from 1.8 MC to 30 MC. It only uses 4 tubes, although one IS a 9 pin double tube, and the rectifier is solid state. It has no RF stage, and only one IF stage; yet, considering all that, it is actually a good performer throughout its coverage. If you were disappointed by it, perhaps it was the quality of the construction. Mine works very well for a glorified All American 5, and so did all the other ones I have known.

RE: National NC-60-Special - mikethedruid - 11-15-2021

The 40 MFD filter condensers arrived today, so I have finished all the under chassis work on the National NC-60-Special. I have done a basic alignment, during which time I found the band switch was VERY scratchy, so that got a good cleaning and is now drying before I continue later tonight with final alignment. It is working pretty well on all bands, and I look forward to checking it out on my outside antenna once all the bench work is done. Here is what the under chassis looks like with the filter condensers installed. They are on the right, attached to the long terminal strip, near the speaker.

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RE: National NC-60-Special - Radioroslyn - 11-15-2021

The power supply was a father/son project. The receiver came from one of my dad's buddies that he knew thru the fire department. Dad was a volunteer and his friend a photographer for the local newspaper. He was a ham also. One day Dad needed to pickup some pictures from him so I went along for the ride. When we got there he was on his 75mtrs hb rack mount tx and Collins 75A* rx. He invited to the mic I said a few words to the fella up in NY (I was living in MD back then). The P/S was mounted down in the bottom of the 6'rack. It used a pair 866A that flickered when I spoke into mic.
By the end of the visit I was given the BC-454/ with the tuning knob and a Surplus Conversion manual which has all the info to get it to work.

When we got the parts together we started in on the p/s. Aluminum chassis, 2 long blue selenium rectifiers, an used power transformer, a couple of 6v filament transformers (needs 24v for the heaters. 24v transformer weren't all that common back then) and a 40mfd 450v capacitor.

Wired up the 5v & 6v to get 11.3 then the other two 6v transformers which make 23.9v for the heaters. The hv ended up at abt 200v using the 40mfd brute force filter. It still had some hum so later on I fitted a choke and a 2nd cap. It got rid of the hum.

Next was the control panel. BFO switch, 1/4' headjack and rf/IF gain control all onto a rather small piece of aluminum. Then I was ready to go...
Later on I also retuned in to cover 3.5-7.5mc so I could get both 80 and the 40mtr ham bands. Over the years I've had all of the lw/hf receivers and most of the hf tx's.

de N3GTE

RE: National NC-60-Special - mikethedruid - 11-15-2021

Did final tweaking of the alignment tonight. I am rather pleased with this radio. It definitely outperforms both my Philco 66 and my 38-10. It is also a noticeable improvement over the SW-54. The BFO works very well, and I had no problem listening to hams on SSB on the 40 meter band. I could pick up WWV on both 5 and 10 MC. I could pick up lots of regular shortwave stations too in the international bands between 5 and 7 MC and the ones between 9 and 10 MC and 11 and 12 MC. Despite a lot of hash from the power lines I could pick up several stations on band 2 between 3.5 MC and the top of the band. The regular BCB was very good. WSM 650, Nashville, came in quite clear despite the hash, and above that where the hash fades out I picked up 700 WLW from Cincinnati, 710 WOR from New York City, and even 740 CFZM, Zoomer Radio in Toronto Canada ! Things continued just as well right on up the dial, 1510 WLAC, Nashville and 1530 WCKY in Cincinnati both came in very clear. I'm quite happy with the results. Now I just have to put the radio back in its cabinet, put back the fiberboard back, and it will be all done for another half century or more. It is actually so good I may use it for a daily driver for a while.

RE: National NC-60-Special - radiorich - 11-15-2021

Hello mike,
What great looking radio and I have a Hallicrafters S-38 waiting to restore maybe if I get time this winter.
Sincerely Richard

RE: National NC-60-Special - mikethedruid - 11-18-2021

The NC-60-Special is DONE ! I re-painted the cabinet, which was looking tired and had a few spors beginning to show rust stains. Cleaned it well with mineral spirits, then sanded it with 400 grit, and cleaned it with mineral spirits again. Then painted it with flat grey spray enamel, let it dry overnight, then baked it in a 200 F oven for about an hour to harden the paint. When it had cooked well I masked it with masking tape and newspaper, and shot the flat black. Then I let it sit overnight again, and baked it again. Meanwhile I took all 4 knobs and carefully scrubbed them with mineral spirits and a toothbrush to remove the brown staining on them. When everything was done, I reassembled the radio; put the guts back in the cabinet, and did final testing. It works and looks like new !

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