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#1
10-09-2010, 06:06 PM
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National SW-54
Many years ago, a friend of the family gave my mom this National SW-54.
 At the time, my parents were really into CB radio and our friend, who had served in the air force, had quite a collection of equipment. He said this one didn't work and said that she could have it. Oddly enough, it ended up sitting in the floor somewhere or another. One day, my mom's foot collided with it and she was bent on chunking it out the front door so I convinced her let me have it, instead. I didn't want to see it get thrown away, and while I didn't know anything about it, I knew it was old and that was enough to give it value in my eyes. It's sat on a shelf for several years now, and I've never really thought much about it. Awhile back, someone over at AudioKarma was talking about ham radios and whatnot and I mentioned having this radio and he told me it was a decent entry-level receiver. I looked into it, and sure enough, it was a popular model from the 1950's. It heavy, tube-type, and made during the 50's. That qualifies it as "cool." Since I've been tinkering with vintage electronics lately ( restoring that Zenith television ) I figured I might have a look at it, now that I somewhat know what I'm doing. It was pretty much filthy inside.  It's safe to say that this thing hasn't been serviced in a very long time. Believe it or not, there's a copper-plated chassis under all of that dust.  Despite the copper plating, some pitting has set in. Naval jelly seems to be helping, though. This radio is unique in that the underside of the chassis can be accessed by removing the bottom cover, rather than having to remove the chassis completely. I took it all apart anyways, of course. It's a bit of a mess under there, too. No wonder it didn't work...  All of the original wax capacitors are still present and are long overdue for replacement. There seems to be a crude electrolytic repair where at least one 60MFD from the old can has been left in circuit while a metal multi-section can has been added.  Well no wonder this electrolytic didn't work! It was actually a banana in disguise!   Seriously though, WTF? So, from what I can see, this should be pretty restorable. Phil has an article about this same model of radio on his site and from the looks of it, it shouldn't be too difficult to work on. I don't know too much about this genre of the radio hobby, but if I means I could listen in on some interesting transmissions, I'd be game for giving it a try. The radio would be of much more value restored than it would be in it's current condition, anyways. Best of all, it was free! 
Last edited by RitchieMars; 10-09-2010 at 06:16 PM. 
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#2
10-09-2010, 06:32 PM
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They were made from 1951-57, & were the competitors to Hallicrafters S-38 series. Both of 'em were "Boys' 1st Shortwave" radios, basically glorified AA5s. However, a lot of young people got their starts in SWL/ham radio w/modest sets like these little guys.
__________________
Benevolent Despot
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#3
10-09-2010, 06:44 PM
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Yeah, that was my first thought when I took the back cover off. The layout looked just like a typical AA5, hot chassis and everything.
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#4
10-11-2010, 01:30 PM
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Those are cute little buggers and they work just fine, as long as you understand what they are and don't expect miracles.
If the cabinet has some rust on the outside, Naval Jelly might work. I have used that to treat rust on painted things without harming the paint. There may still be a little gray dot or depression where the rust spot was, but you won't notice that with a hammered gray finish. Follow the directions on the label and try it on an inconspicuous spot before putting it all over the cabinet. Phil Nelson
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#5
10-11-2010, 07:38 PM
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It's funny you mention that, because after reading about the SW-54 you restored on your site, I had already taken your tip about the naval jelly and put it to use. I think I finished it up Saturday night after a few treatments of naval jelly and then giving it a good wax job. Because of the gunmetal color, the bare spots where the rust ate through are hardly noticeable. It looked even better after I cleaned the crud out of the knobs.
 I'll be finishing up my Zenith before I get started recapping this, but it looks like it'll be worth it. Thanks Phil!
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#6
10-12-2010, 11:51 AM
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Hey, that's looking good.
Phil
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#8
10-27-2010, 02:25 PM
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I'm not sure it's a good idea to have the filter capacitor case (- terminal) in direct
contact with the chassis in this AC-DC design. Better check the schematic. By the way, with all due respect to this little machine, I believe this thread is closer to 'antique radio' than 'ham radio'...
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#10
10-28-2010, 09:04 AM
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On side of the line is tied to the chassis, so it doesn't make any difference if the can is contacting the chassis. That set is U/L approved. Chassis is inulated from the case. I personally never like that bandspread arrangement.
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#11
10-28-2010, 04:07 PM
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Quote:
chassis, often the return point of the power supply (= can of the electrolytic capacitor) is insulated from the chassis by a tubular capacitor. That's what I meant.
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#12
10-31-2010, 02:18 AM
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Quote:
Actually, I had considered posting this in the antique radio section because of it's AA5 design. But, since it's a communications receiver, I thought it might be more interesting to hear from folks who might have seen or used one of these before. That and I figured that tinkering with this thing might introduce me to a part of the radio hobby that I haven't explored as of yet. In any case, I had it for years and I was just tired of it sitting around looking miserable. 
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#13
11-01-2010, 10:03 PM
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I found this guy on YouTube who's restoring a SW-54. He's got some pretty good information to refer back to when I get around to fixing up mine.
http://www.youtube.com/watch?v=Xo__b...eature=related
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#14
11-01-2010, 10:34 PM
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Seems like I remember the crew at "Monitoring Times" restoring an SW-54 several years back...They had it spread out over a period of several months' worth of articles..The next one you oughta shoot for would be an NC-98 or even an NC-125...National's "Cadillac" was the HRO series, but they are very anachronistic, having separate coils that you have to change out. Their REAL TOTL-at least more practical- receiver was the NC-183D, which was referred to as "The Bandswitching HRO".
__________________
Benevolent Despot
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#15
11-15-2010, 01:03 PM
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I liked the NC-183 because it had two rf stages, something very few radios had. I never looked closely at the NC-183D. I suspect the frequency stability wasn't exceptional, and certainly the bandspread calibration wasn't fine enough for me. At least, not with Collins having 1 kc per division, and accurate too. By today's standards, even Collins' calibration could be considered a bit sloppy.
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