|Emerson Mod 522 Ebony AM Table Radio ~ c. 1947|
The mid 1940's to early 1950's incorporated a design style known as 'Moderne' and was characterized by modern but somewhat bulbous elements. Examples of Moderne styling were very evident in the look of the 1950 and 1951 Chrysler and General Motors automobiles as well as much of the dark wood furniture of the period. While the Moderne school of design was short-lived (primarily because it was fundamentally ugly), a few successes such as this Loewy inspired radio survived and viewed in retrospect are really quite beautiful and collectible.
The Emerson here was acquired a few months ago and in as-found original condition with the possible exception of the power cord having been replaced. In order to complete the circuit for testing, I also had to replace the burned out pilot light. It is an early model as the chassis uses the older Loctal type tubes. Later 511's and 522's incorporated the miniature tubes.
|The case, front grill and tuning lens|
|Tubular cap upper left|
I have a schematic for this radio, so the next step was to test the tube pin resistances and pin voltages and compare them to the published specs. In addition, I wanted to identify those pins that had anomalies in both resistance and voltage as that would be a great clue as to where in the circuit failed or failing components could be located. Below are my sheets showing the initial readings. Those highlighted in pink were out of spec.
|Initial Resistance Readings|
|Initial Pin Voltage Readings|
+ highlighted are pins with anomalies
in resistance & voltage
The radio was taken apart and the process of evaluating the condition of the cosmetics and the electrical components begun. The original power cord was in good shape but had been improperly spliced into the circuit so I completed the repair to correct that and now it is properly installed.
The above analysis strongly indicated that most of the old paper and wax capacitors were at best in marginal to failed condition and because of that, there was a good chance some of the related resistors had been stressed and were performing outside of spec. I decided to replace all the affected capacitors and those resistors that could potentially fail. Particular attention was paid to the high value resistors as they tend to vary greatly as they age.
Below is a picture of the (almost) completed work on the chassis...one high value resistor has to be changed and I'm waiting for a supplies order to arrive so I can do that.
Below is the Voltage Measurement chart updated to this point. The highlighted numbers are the correlated cap and resistor anomalous readings that should resolve after R21 is replaced.
|Updated Pin Voltages|
While waiting for parts, I turned to the cosmetics. The case was thoroughly cleaned with a very gentle solution of dish washing detergent and soft bristle brush. Bakelite is not like other plastics; you cannot "polish" a dull case as the original shine was baked on and cannot be restored if removed. There are some methods for emulating a bakelite shine, but luckily, I did not have to employ them here. As it turned out, this case is really nice and the shine was preserved as a soft ebony glow which is what you want with unpainted bakelite. After cleaning and removing a couple of old paint spots, I waxed it with a carnuba based automobile wax.
The front metal grill was in pretty good shape and I touched up a couple of places that were stained. The dial lens was a little hazy so I used a plastic cleaning compound to clear it up. The yellow tint is patina and a function of the radio being 77 years old. I don't try to rub out the tint as I think it makes the radio look original and adds to the character. Further, it in no way affects the dial light's ability to individually illuminate the station numbers.
The picture at the beginning of this article is the finished radio.
©2015 David Simons Big River Mercantile