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Echophone EC-1 Beginnings

If you saw my previous posts Echophone EC-1 and The Echophone EC-1 Unboxing you will know that I put off the restoration of this little gem of a radio until such time as I was able to spend some more time on it. As often happens with these tasks, it never really is about the time, but more about finding the headspace to allocate and finding the motivation.

A great deal of organisation and pre-work goes in to any such restoration, even if the final result is not to have it look exactly like it came out of the factory yesterday. So it is that I find, despite having many other things on the go, including moving house, a very busy career, commitments in music and cycling, I have somehow found the motivation to begin.

For those of you who have never undertaken such a task as restoring old radio equipment, I will be pleased to document the process here and via Youtube. The EC-1 is a very simple radio- a variant of the All American 5 chassis. This design is quite simple and therefore very common in earlier radios, but is is not particularly safe- it requires some modifications to make it safer. Restoring valve radios often means dealing with lethal voltages, so if you undertake a restoration yourself, you do so at your own risk. I am not an qualified technician, just a holder of an Advanced Amateur Operators Certificate of Proficiency (AOCP), the highest licence category for amateur radio operators in Australia. I am certainly not an expert. In fact when it comes to radio repair, I am entirely self-taught. If you wish to see someone far more skilled than me restore the same radio model, you can go to the video below.

Screen Shot 2017-07-29 at 8.25.19 PM

The first steps for me after obtaining the radio and inspecting it are now underway.

  • obtain circuit diagram (done)
  • if possible obtain alignment procedure (done)
  • Make a list of components to replace- all capacitors other than silver mica and possibly some resistors depending on how they test
  • construct several pieces of test circuits such as impedance matching circuits for connecting test equipment to the radio

As I work my way through the process of restoring this radio, I will post updates here.

WARNING STATEMENT

As they are wired from the factory, these radios are deadly dangerous and you shouldn’t even plug them in until they have been made safe.  These radios have what is called a “hot chassis,” and that makes them very dangerous to work on or even to plug in.  Do not attempt to test or repair them until you or a skilled technician have rewired them as I will describe below.  I can not emphasise too strongly how important it is that you follow my advice because over the years, many people have been killed by “hot chassis” radios and many others have received painful shocks.  The fact is, the modifications I shall describe are not only very effective, but are quite easy to do and will cost you less than $10, so there is no excuse for not doing the work.

Why are these radios so dangerous?  Depending on which way their original unpolarized plug is plugged into the wall socket, the chassis of these sets have a 50/50 chance of being “hot” if turned on and a 50/50 chance of being “hot” if simply turned off.  On or off, the chassis will be hot at some point and you will get a bad shock if you simply touch the insides of the radio.  To make matters really deadly, if the grommets that insulate the chassis from the outside case are in bad shape, you will get electrocuted just touching the radio.

How did Hallicrafters and other manufacturers of  “hot chassis” radios get UL approval to manufacture and sell such dangerous radios?  Back when these radios were new, there were no polarized wall sockets and power plugs so radio manufacturers made them safe by insulating the case from the chassis with rubber grommets or by putting the chassis in wooden/plastic cases.  All these radios had Masonite rear covers that prevented probing fingers from touching the chassis and they all had bold warning labels telling you NOT TO TOUCH THE CHASSIS OR CHANGE THE TUBES WITH THE BACK OFF AND THE SET PLUGGED IN. The warning labels said that the set was to be worked on only by a Trained Radio Technician (who knew what a “hot chassis” was).

We can’t trust the old safety devices anymore because the insulating grommets have deteriorated with age and the Masonite backs of most of these old radios are now missing.  Even if they were still there, the warnings that were printed on the backs of these radios are equally useless because The Trained Radio Technician profession has been extinct for decades.  Today we have to be our own “Trained Radio Technician” and the truth is, most of us aren’t “trained” and most of us don’t even know what a “hot chassis” is.  The whole idea of this essay is to give you the training you need to make your radio safe before you try to fix it or use it.

73 de VK2KMI
Kimberly

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