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Posted by: Adric
« on: July 05, 2018, 10:09:32 am »

One of Mom's more difficult relatives in town had an old and very large radio in a handsome cabinet that had long since quit working.  She just used it as a table for displaying her decorative trinkets, but one day she decided she would give it to me instead.  Dad and I looked it over and of course the first thing we did was take all the tubes to the 7-Eleven to check them out.  There were several bad tubes.  We bought replacement tubes, plugged them in, and the thing worked fine.  It picked up radio broadcasts from all over the world.  I thought it was a great gift.

So Mom bragged to the relative that we fixed it, and guess what?  She wanted it back! :(  That was the last I saw of my radio.  Dad and I were both disappointed.  There is such a thing as too much information (TMI).
Posted by: stevieweeks
« on: June 16, 2018, 09:26:38 am »

Just an aside on safety...

This radio had to have its power supply modified in order to replace the components removed with the speaker.

This entailed adding a small aluminum chassis containing a choke to replace the speaker field coil and a replacement output transformer... at the time,  Stevie added a three wire polarised and grounded power cord as well as a fuse to the A.C. supply; together with the fact that this radio has a transformer power supply (it is not an AC-DC receiver), and all of the failure prone components have been replaced, this radio is pretty safe to operate... nevertheless, Stevie NEVER leaves it playing without close supervision... and he unplugs it when it is not in use and all...

This brings us to a discussion of the All American AC - DC 5 tube radio... (it is most likely that this type of circuit was rarely used in Europe due to the higher line voltage but Stevie may be wrong about that)
 
These radios were the most common type produced between about 1938 and 1968 or so... untold millions were produced... and they have characteristics which render them inherently unsafe... they can be used, but you should be aware of the risks involved with them...

They do not have power transformers... one side of the chassis was directly connected to the house neutral, and that is one of the main dangers... if the two prong plug is inserted the wrong way, the radio will still play perfectly normally, but the chassis will be connected to the live side of the AC power... which obviously presents a severe shock hazard...

If the tubes in the radio have numbers starting with 50 and 35 (50L6, 35Z5, 50C5, 35W4 for example) the radio is an All American AC - DC type... and it most likely is one of these...

By 1940, CSA and UL standards called for protection which was mostly in the form of totally insulating the chassis with non conducting material...

NEVER OPERATE ONE OF THESE RECEIVERS WITH THE METAL PARTS EXPOSED... turning it on by touching the metal shaft of the volume control may well be the last thing you ever do and all...

Stevie actually does work on these out of the cabinets but does so with EXTREME caution... he tests with a meter to ensure that the chassis is not live before touch anything on them...

They are also not equipped with fuses, so there is also the potential for disaster there if something fails catastrophically in the circuit... particularly the large output capacitors...

The design was altered to supposedly be fail safe after the war... but it's probably better not to take a chance and never leave them operating unattended...

By the way, if you do find an old piece of electronics in the attic, please resist the urge to plug it in and see if it works. Apart from any safety issues, the likelihood is great that the filter capacitors will have deformed and will fail catastrophically and cause major damage to the equipment (remember the 'fail safe' requirement?) if power is turned on carelessly... there is a method for safely doing this, but Stevie usually just replaces them unless the radio is of exceptional value... modern electrolytic capacitors are far superior to those of sixty years ago...

If you do want some advice about tube electronics, Stevie will happily oblige... except that he won't give you a definitive answer to 'what is it worth?' since that particular question is a potential minefield and all... he will point you to some resources and advise taking them with a grain of salt...





 
Posted by: Emlyn Morgan
« on: June 16, 2018, 05:19:35 am »

Very nice. Can you get Mrs Dale's Diary on it? (-:
Posted by: Jack
« on: June 16, 2018, 03:48:59 am »

I had forgotten about having to wait for things to warm up.
Posted by: stevieweeks
« on: June 15, 2018, 09:41:21 pm »

It's fascinating to see youngsters react to tube electronics...

They turn them on and announce loudly "It's Broken!!!"...  :o

The concept of waiting for the tubes to warm up is completely foreign to them... they're used to electronics being nearly instantaneous and all...

Posted by: stevieweeks
« on: June 14, 2018, 10:13:33 pm »

Actually, it doesn't sound too bad considering it is an eighty-two year old AM radio; of course, it's not all original since the speaker was removed.

It has a modern 12" speaker and Stevie replaced the output transformer with one he had on hand which is probably much larger and higher quality than the original unit and all, which, along with the necessary changes to the power supply to replace the speaker's field coil, have probably increased the bass response and reduced the distortion levels somewhat...

Stevie.
Posted by: David M. Katz
« on: June 14, 2018, 08:40:38 pm »

Beautiful job!

Posted by: Padraig
« on: June 14, 2018, 06:48:56 pm »

looks great. how does it sound?
Posted by: stevieweeks
« on: June 14, 2018, 02:28:35 pm »

1936 Canadian General Electric Model A58 Console Radio playing AM 740 Zoomer Radio...



No, it's not correct...  those areas of lighter wood should have been stained dark; if this radio had been worth anything, Stevie would not have refinished the cabinet in this manner...

For starters, consoles are not generally worth as much as table models;  this was originally a mass market middle class item very much along the lines of a Pontiac Six, it has no special features beyond the fact that it has shortwave capabilities.

Secondly, it was a basket case when Stevie found it... some moron had removed the speaker not realising that it was an electromagnetic speaker that would not work without the radio's power supply. Stevie had to cobble up a little unit to replace the field coil and the output transformer, which was also mounted on the absent speaker and all.