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October 4, 2005
I discovered this in a local antique store a few months ago, but the $129 price tag put me
off. The other day I returned, and saw it again. The owner noticed me looking at it, and offered
to sell it to me for $75. So, like a fool, I agreed. Today I picked it up, and here it is.
This is not the natural color or grille cloth for this set. Somebody made an art project of it, unfortunately. The cabinet was "antiqued" with streaky tan paint. Yuck.
Good news when I fired it up on the dim-bulb tester. It works. Bandswitch is filthy (so is everything else) and it hums and plays weakly, but it's good to know there aren't any obvious major component failures. I checked the tubes. All but the 6H6G, 6L7 (a metal tube, not original) and 5Y3GT were middling-to-weak. And the latter two are two tubes that are not staying in the set. They'll be replaced by 6L7G and 5Y3G. So I get to replace 10 of the 11 tubes in the set. Lucky me.
There are a lot of paper caps in there. I counted 26, which is a very large number for an 11-tube set. This ought to deplete my stock of new mylar caps rather quickly. Oh well. It'll be worth it when it's done.
The Silvertone 4587A's tube lineup includes:
| 6K7G | RF amplifier |
| 6L7G | Converter-Mixer |
| 6C5G | Oscillator |
| 6J7G | AFC Control |
| 6K7G | IF amplifier |
| 6H6G | Detector, AVC, AFC |
| 6Q7G | 1st audio |
| 6C5G | Phase inverter |
| 6N6G | Power amplifier |
| 6N6G | Power amplifier |
| 5Y3G | Rectifier |
October 13
First order of business is to replace the three electrolytic caps in the power supply. Replacing these will kill the hum and make the power supply work correctly.
I notice that the three can caps here are not original. They're Mallory brand caps, probably installed in the '50s. I suspect that the originals had terminals on the bottom for other wires to connect to. These have leads poking out the bottom. The result is that this whole area is filled with flying junctions (connections made in midair instead of being tied at a terminal.) One was insulated with a tight roll of electrician's tape; another (carrying high voltage!) is bare. Yikes.
I found a nearby hole in the chassis and used a machine screw and nut to bolt a terminal strip down to the chassis. Then I cut all the flying junctions apart with my trusty small diagonal cutters and mounted three new filter caps correctly to the terminals along with all the wires that connect to them. Small dikes are nice in a chassis like this where working space is rather tight. The results:
While I was in there I spritzed the bandswitch with cleaner. Let it dry, then I turned the chassis back over, attached the speaker and fired it up. There is some nerve-rattling crackling and popping coming from somewhere underchassis. I shut it off, turned it over again and turned it back on upside down. The popping was coming from somewhere around the bandswitch. Probably needs another cleaning.
Nonetheless I let the set run, and shortly thereafter was rewarded with a local station booming in on the American band. For fun I flipped it up to the foreign band and immediately picked up stations in the 31 meter band. I was really pleased by that. There were stations at the low end of the Police band, where domestic stations above 1500 kHz are now. So all three bands work. Nice. It's a really good sounding set too, even with weak tubes and the speaker out of the cabinet. Speaker is kind of rattly though. There's one tear, and the voice coil probably needs recentering. Oh well. Can't wait to hear it fully done.
I just hope I don't break the flash tuning mechanism before then. See the big toothy half circle on the chassis? It's part of the flash tuning. When a contact that moves with the dial pointer touches a bent-up tooth on that wheel, a light lights up that shows you where a station is tuned in. Unfortunately that wheel is really in the way when turning the chassis is upside down - it wants to rest on the wheel and bend it. So I've had to improvise a chassis jig for now, something I haven't needed to do before. Maybe someday I'll make or buy a real chassis jig. Sure could use it now though.
October 14
A reasonably productive day. I pulled out the compressor and gave the chassis and speaker a thorough blast of air to clear the dust - then had a coughing fit. Wow, there was a lot of dust.
Good news was, that fixed all the popping on startup. I think now it was coming from the tuning cap and the dust was causing it to short a little.
Also pulled the dust cap off the speaker cone and blasted out the voice coil with air, blew the rest of the dust out of the speaker, and fixed a tear in the cone. I sprayed 3M Super 77 spray glue on the rip, then laid an appropriately sized piece of coffee filter onto it when it got tacky. This worked great. Now the annoying speaker rattle is gone.
Also replaced four caps. That's it for the day, but the set is working nice for the moment.
October 15
Recapping continues unabated. This is a difficult set to work on, because of the tight spaces. I only got nine more paper caps replaced, along with the last electrolytic. Much of the time was spent figuring out a wiring difference between the actual set and the schematic. There were five wires shown on the schematic as being connected at the RF coil, and all went through a .05 cap to ground. Instead, only two of the wires had the cap to ground, and the other three were soldered together in a flying junction and had their own .05 cap to ground. I tried connecting it as per the schematic, but the set never worked right that way. So finally I gave in and installed a terminal strip in the set, then mounting the floating connection to it. It works. Whatever.
The replacement of paper caps is half done. Thirteen down, thirteen to go. I have the entire right side of the underside of the chassis done. It looks like this:
The whole left side remains. When I get time I'll try to finish it up, and hope that it goes easier than the part I've done. I'm also still getting an occasional pop and spark on startup. I don't like that, but haven't found the cause yet.
October 17
I finally found my heat gun and scraper. Accordingly, I think I will shift my focus to the cabinet for awhile to see if I can get it stripped and refinished before the weather gets too cold to spray. I stripped the paint off half the top tonight. The finish underneath looks okay but will need a couple new coats of lacquer to look nice. It's darker than I expected, and disappointingly there doesn't seem to be much of a grain pattern. But other Silvertones like this look pretty much the same, so I guess it's all right. I'll keep at this and see how it goes; it's rather slow work.
October 18
A while ago I noticed that the address and phone number of the first owner of this radio is written on the guarantee tag attached to the speaker. This was a local set; the address was in a neighborhood that was middle class in 1937 but unfortunately has declined badly in recent decades and is now one of the poorest neighborhoods in the city of Milwaukee. For fun early this morning since I was headed through the area on my way to work I thought I'd drive over and see what the house looked like.
So I approached the address, which was a block off a main drag. Then I found that the street I needed to turn onto was no longer there. Three square blocks had been torn down 15 years ago to put up a steel refinishing factory, and this house was on one of them. Too bad.
Anyway, tonight I used the heat gun to strip the top and half the left side. I haven't used this technique before so the results are fair to middling at best. It's nice I'm not removing the old lacquer, which will provide a nice base for the new coats that will be necessary. The top shoulders are solid cheap construction wood with unattractive grain that will have to be heavily toned to look good. The bottom rear of the left side is badly delaminated and will need gluing after the cabinet is stripped. It's really ugly now, so no pictures. Just know that it's ugly. Nonetheless, work will continue as time permits.
October 19
This was stripped, sanded lightly to get rid of the residue and washed off with mineral spirits. If I spray new lacquer on top, it should look like this. Not too bad. Gives me incentive to finish.
October 20
Yet more stripping. Yawn. But it's going faster. The right side and front are done and the trim is maybe a third complete, which means paint removal should be done in another hour or so of work. The cabinet is returning to its original dark walnut shade. The bad news is the condition of the finish underneath. The heat is not doing the lacquer underneath any good. It appears I'll have to wash the cabinet with acetone and lacquer thinner and refinish it. It's really a mess with paint residue and paint scraper marks caused by my own clumsiness. Trying to sand off some of the residue with a mineral spirit-soaked pad caused me to cut right through the toner in some places, leaving light spots. Panels with this problem will definitely have to be stripped and redone. I swear, I don't know why I make these jobs so much harder for myself.
October 21
All that's left to strip are the base and grille. This is the most complicated part of the cabinet. Not looking forward to doing it.
Took the grille cloth off the board. It was attached with about a million tiny little tacks. The quality of work was actually pretty good. It's a stiff cloth and was attached nice and tight. The old cloth was thoroughly removed too. The glue that held it on is still evident, but all that's left of the cloth is a few tiny threads. It's just hard to fathom. Why did they do it? If only the radio could talk...
October 22
Well, the misery is finally over; I've finished stripping the paint off the cabinet. My guess of an hour was a bit optimistic, but no matter. It's done. And the cabinet looks bad, with residue, melted lacquer, scrapes and oversanded light spots. I think the only advantage for my using the heat gun instead of paint stripper is that the mess that needs cleaning up is nice little dry paint chips that can be vacuumed up instead of a disgusting toxic slime of melted paint and methylene chloride.
Also, I have a pretty good guess at how the underlying finish should be colored. The attractively veneered sides that wrap around to the front should be a medium walnut, while the rest of the cabinet should be dark walnut. The original ad for this radio mentions its two-tone finish. I guess those would be the two tones. I've seen another photo of this radio on the Internet that is shown colored this way, and it looks nice. That's what I'm going to aim for.
Next order of business is to strip the lacquer off, sand where it needs sanding, repair the delaminations on the bottom, and refinish. Hope I get to this all next week as the weather improves slightly.
October 26
This is the cabinet after the first go-around stripping with acetone and lacquer thinner. I did the whole cabinet. I could have kept the original finish nice if I had been more careful with the heat gun. But with both sides showing veneer damage, and a big water stain in the finish on top from a decades-ago plant, I would have been tempted to refinish the thing anyway. Maybe that's why it was painted years ago. Oh well.
After I took the picture I cleaned the rest of the old lacquer off, and I also glued the big delaminations on the left and right sides. I also called RadioDaze for a piece of similar-to-original diamond-patterned grille cloth and a few new 0.1uF caps to refresh my stock. Recapping this chassis pretty much cleaned me out.
Next up: Fix a number of small chips in the veneer, and some much larger ones at the bottom of both sides where the veneer delaminated and some long, thin pieces chipped away. Light sanding of the solid-wood trim to eliminate chips and jagged cuts. One more wash with 0000 steel wool soaked in clean lacquer thinner, and a wash with 0000 steel wool soaked in mineral spirits to make the wood nice and smooth. Already it's so smooth I can see and feel that I will not have to apply paste grain filler, which is a nice bonus. After washing with mineral spirits I'll be able to mask off the veneer and start coloring the trim with dark walnut spray toner this weekend. I hope....
October 27
I did the repairs using walnut wood putty and the final scrubdowns (and final picking of bits of paint out of the corners and crevasses. Sheesh. I'm never working on a painted cabinet again...)
This weekend I will be finishing the cabinet. First I had to tape off all of the veneered area, and it looks like this.
The trim will be toned very dark. You see how blotchy it is. This is normal after stripping. You cannot stain this. It has be colored with toning lacquer. And I'm out of dark walnut toner, so I'll have to stop at Rockler tomorrow and get some. After this is sufficiently dark, I take the mask off the front and top and give that a spritz or two; enough to make it match colors but hopefully not enough to hide the grain.
After that, then the mask comes off the sides and these are toned with a coat or two of medium walnut. I do it in this order because this way, if I overspray onto already-toned parts of the cabinet, it can't be seen.
Next update Saturday, if all goes well.....
October 29, 2005
It's all good.
I finished the cabinet completely. First was the toning, following the plan above. Then some touchups with alcohol stain and magic markers. After this, I had time and weather on my side, so I pulled the gloss lacquer off the shelf and applied six coats. Two at a time, with a break in between.
The cabinet looked great afterwards. I let it dry thoroughly, then took the rottenstone and a bottle of mineral oil and rubbed out the finish. And this is how it turned out.
Since the picture was taken I reattached the escutcheon. And I'm annoyed with myself, because I dropped one of the screws and can't find it. I'll have to look for a replacement. And I wish I had ordered my grille cloth earlier, because I was hoping it would arrive today but it didn't. I'll have to wait until it does to attach it to the speaker mounting board, then screw that back into the cabinet. Then as soon as I finish the chassis I can install it and this set will be done. Probably within a week, I'll get to enjoy the fruits of my labor.
October 30
Replaced all thirteen remaining caps tonight. And the radio still works!
Works better than ever, actually. Very sensitive, very selective, great sound. Time for burn-in. This is where it's on all the time for several days, just to make sure nothing goes wrong. If not, it's going back into the cabinet and this puppy is done. For now, it's off to take care of the finger I burned on the soldering iron, and bed.
Chassis notes:
1. There are two deviations from the schematic in the RF stage. The first at the grid of the 6L7G tube. The schematic shows the grid cap tied directly to the trimmer and bandswitch. In this set, the grid cap is connected to a small resistor and mica cap mounted on top of the tuning capacitor. The location of this assembly is critical; moving it will detune the radio. From there, the cap is connected to the trimmer while the resistor is connected to the lower point referenced immediately below.
The second change is that the link circled in the schematic section below does not exist. The lower point has its own .05uF cap to ground which is not shown in this schematic. Also connected to this point is the resistor that sits on top of the tuning cap, connected to the 6L7G grid as mentioned above.
2. The tube lineup with which this set will go into use has been determined. As found, this set had the following lineup: 6K7GT RF, metal 6L7 converter, 6C5GT oscillator, 6J7G AFC, 6K7GT IF, 6H6G detector, 6Q7G 1st audio, 6C5G phase inverter, 2x 6N6G audio output, 5Y3GT rectifier. Many of these tubes were weak, and I was not pleased with the look at the back of the chassis. The original tall 6K7G shields had been replaced with little short shields appropriate for a GT sized tube, and there was no shield at all on the 6L7. I only had one spare tall shield. So I installed a 6L7G and put my tall shield over it, and swapped the shields on the 6H6 and 6K7 IF tubes. The 6H6G was replaced with a metal 6H6, which is hard to see near the front of the chassis. A good metal 6K7 was installed in place of the weak 6K7GT RF tube. Both 6C5s were replaced with 6J5Gs, and the 6J7G and 6Q7G were replaced with identical good tubes. A good 6K7G was installed in the IF position and a good 5Y3G in the rectifier socket. I haven't done anything about the 6N6Gs yet. At any rate, this puts tall G style tubes in the obvious positions on the chassis and hides the two short tubes near the front where they're hard to see, presenting a more original "back of the chassis" look.
October 31, 2005
The grille cloth arrived today. So I installed it, assembled the radio, and that's it. After nineteen days in the shop the radio is, for all my intents and purposes, done. It's not perfect. Maybe you don't call it restored. Refurbished, perhaps. It looks nice and works reliably. I'm satisfied.
Here's the chassis, all recapped:
And here's the radio all assembled.
I hope to enjoy this one for years to come.
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