Teeny 1938 metal "Mighty-Mite" radio

[decojoe67]

Between 1938 and 1949, Arvin produced a slew of little rugged metal radios. This is the earliest and toughest to find model 40. It's also the only one that sans the Arvin name for "Mighty-Mite" on the escutcheon. It has only two tubes that do the job of 4. When I saw the opportunity to acquire this excellent original ivory example, I went for it.
I put a typical 1960 transistor radio next to it for comparison, so you see just how small this cute set is!:

[Electronic M]

Back in the fall I grabbed it's IIRC 4 tube cousin for $20...they are cute little sets.

I'd imagine a collector with a squaw at war with their collection probably has a few hidden in the couch cushions to get their radio fix.

[decojoe67]

Originally Posted by Electronic M

Back in the fall I grabbed it's IIRC 4 tube cousin for $20...they are cute little sets.

I'd imagine a collector with a squaw at war with their collection probably has a few hidden in the couch cushions to get their radio fix.

LOL - They do have a lot more charm in person than in a photo. The original ivory paint they used back then is so appealing with that almost porcelain finish.
I had gotten my favorite model a while back. The 1940 5-tuber model 502 with the bump-up on the right side top. That was has a great little deco dial with a dial lamp. It's a very good performer too.

[jr_tech]

Beautiful example! I never have seen the 2 tube model... is the 25B8 ok?

jr

[decojoe67]

Originally Posted by jr_tech

Beautiful example! I never have seen the 2 tube model... is the 25B8 ok?

jr

Thanks. The condition is what drew me to this one. It seems the 25B8 is good. I would hate to search for a replacement. It's probably easier to just buy a rough radio that has it.
It's strange only have two tubes and so far is proving to only play adequate. I have a bit of garble in the audio (it's had a full chassis resto) and other than using my AM transmitter, I don't hear much of anything across the dial. The later 4 and 5 tubers, in comparison, are surprisingly good players.

[Jeffhs]

About 40-45+ years ago, I had an Arvin model 540T 4-tube metal cabinet radio. The radio worked amazingly well in my area at the time, a suburb of Cleveland, using only the supplied wire antenna. Unfortunately, the set got lost in a move in 1972, IIRC; the photo of the 1938 Arvin Mighty-Mite attached to your post, however, reminded me of my green metal-cabinet 540T. These sets worked well in very strong to strong (read suburban) signal areas, but due to the simplified circuit (I think mine was the 4-tube model) they wouldn't have worked well or even at all in areas some distance from the nearest local AM stations, such as the village in which I live today (there is only one local AM station here, and that is a 1kW 24-hour talk station in the next town south of me; the local AM stations serving Cleveland are 30+ miles away). The 540T (and probably also your Arvin Tiny-Mite) does have an external antenna terminal, so it would be usable in an AM radio fringe area; however, due to the simplified RF signal circuits in both the 2- and 4-tube versions, I wouldn't expect super DX performance from either. I would also suggest that a lightning arrestor be used with any external AM antenna connected to this or any AC-DC tube radio, for safety reasons.

One thing I did not care for with this radio (the Arvin 540T, although this applies to any AC-DC hot-chassis radio), though, was the hot-chassis design. Depending entirely on which way the AC plug was inserted in the wall socket, the chassis and even the cabinet (the latter depending on the condition of the grommets insulating it from the cabinet), not to mention the external AM antenna terminal, would carry the entire AC line voltage, needless to say causing a shock hazard. Anyone who would put a radio such as this in a kitchen, bathroom or other wet area is, of course, asking for trouble.

IMHO, he best thing to happen to the All-American Five radio (which followed these two-and four-tube Arvins), IMHO, was when these sets were replaced by full-transformer powered AC tube sets and/or battery powered solid-state radios.

I cannot emphasize strongly enough that a kitchen, bathroom or any other place having wet areas is no place whatsoever for an AC-DC tube-powered radio. Too many lives were lost when these sets accidentally fell into or were pulled into sinks, bathtubs, etc. full of water. The home's line fuse for the bathroom, etc. circuit would have (or should have) blown at once as soon as the radio hit the water, but in many cases (such as overrated fuses in the basement fuse box) these fuses blew too late, or if the homeowner replaced the fuse with a copper penny. The latter was a dodge often used in the '20s-'50s when the correct fuse was not available; the circuit was restored, but the circuit was now very dangerous. When the fuse was replaced with the penny, large amounts of electric current would then enter the wiring, causing a fire, since there was now no fuse or breaker to open the circuit. This practice was stopped dead in its tracks when new homes were constructed and wired with circuit breakers, which cannot be bypassed; the only way to restore the circuit is to flip the breaker back to "on". If the breaker trips again, there is a dangerous overload on that circuit which must be corrected.

BTW, I seriously doubt that Arvin, or any other radio manufacturer, was making radios for civilian use between 1941 and 1946, as all civilian production of radios and just about everything else came to a screeching halt starting in '41, at the beginning of World War II; civilian production of these sets, and everything else, would not resume until the war's end in 1946-'47.

[decojoe67]

Originally Posted by Jeffhs

About 40-45+ years ago, I had an Arvin model 540T 4-tube metal cabinet radio. The radio worked amazingly well in my area at the time, a suburb of Cleveland, using only the supplied wire antenna. Unfortunately, the set got lost in a move in 1972, IIRC; the photo of the 1938 Arvin Mighty-Mite attached to your post, however, reminded me of my green metal-cabinet 540T. These sets worked well in very strong to strong (read suburban) signal areas, but due to the simplified circuit (I think mine was the 4-tube model) they wouldn't have worked well or even at all in areas some distance from the nearest local AM stations, such as the village in which I live today (there is only one local AM station here, and that is a 1kW 24-hour talk station in the next town south of me; the local AM stations serving Cleveland are 30+ miles away). The 540T (and probably also your Arvin Tiny-Mite) does have an external antenna terminal, so it would be usable in an AM radio fringe area; however, due to the simplified RF signal circuits in both the 2- and 4-tube versions, I wouldn't expect super DX performance from either. I would also suggest that a lightning arrestor be used with any external AM antenna connected to this or any AC-DC tube radio, for safety reasons.

One thing I did not care for with this radio (the Arvin 540T, although this applies to any AC-DC hot-chassis radio), though, was the hot-chassis design. Depending entirely on which way the AC plug was inserted in the wall socket, the chassis and even the cabinet (the latter depending on the condition of the grommets insulating it from the cabinet), not to mention the external AM antenna terminal, would carry the entire AC line voltage, needless to say causing a shock hazard. Anyone who would put a radio such as this in a kitchen, bathroom or other wet area is, of course, asking for trouble.

IMHO, he best thing to happen to the All-American Five radio (which followed these two-and four-tube Arvins), IMHO, was when these sets were replaced by full-transformer powered AC tube sets and/or battery powered solid-state radios.

I cannot emphasize strongly enough that a kitchen, bathroom or any other place having wet areas is no place whatsoever for an AC-DC tube-powered radio. Too many lives were lost when these sets accidentally fell into or were pulled into sinks, bathtubs, etc. full of water. The home's line fuse for the bathroom, etc. circuit would have (or should have) blown at once as soon as the radio hit the water, but in many cases (such as overrated fuses in the basement fuse box) these fuses blew too late, or if the homeowner replaced the fuse with a copper penny. The latter was a dodge often used in the '20s-'50s when the correct fuse was not available; the circuit was restored, but the circuit was now very dangerous. When the fuse was replaced with the penny, large amounts of electric current would then enter the wiring, causing a fire, since there was now no fuse or breaker to open the circuit. This practice was stopped dead in its tracks when new homes were constructed and wired with circuit breakers, which cannot be bypassed; the only way to restore the circuit is to flip the breaker back to "on". If the breaker trips again, there is a dangerous overload on that circuit which must be corrected.

BTW, I seriously doubt that Arvin, or any other radio manufacturer, was making radios for civilian use between 1941 and 1946, as all civilian production of radios and just about everything else came to a screeching halt starting in '41, at the beginning of World War II; civilian production of these sets, and everything else, would not resume until the war's end in 1946-'47.

Interesting. I didn't realize how dangerous these little sets could be! Likely these were used in kitchens very often. The novice electronics guy I am, I was poking in the chassis like a toy while it was on! eeeek!

[Electronic M]

Originally Posted by Jeffhs

BTW, I seriously doubt that Arvin, or any other radio manufacturer, was making radios for civilian use between 1941 and 1946, as all civilian production of radios and just about everything else came to a screeching halt starting in '41, at the beginning of World War II; civilian production of these sets, and everything else, would not resume until the war's end in 1946-'47.

Philco sold consoles based on car Radios in 42-43 to use up the wearhouses of car Radios left unused when Detroit switched to war production....wood was still readily available for civilian uses then and I guess they could still get sufficient parts to change the power supply. There were also the civilian gray metal cabinet detrola radios sold in 1945-46....the government ordered them as morale radios for opperation downfall (invasion of Japan) but little boy and fat man ended the need for the opperation. The radios were already built when uncle Sam cancelled the order so detrola shaved off the metal handles, painted over the olive drab with silver and sold them to the desperate radio starved masses....there are probably a few other examples especially if you count civilian sets that got beefed up to mil/navy spec (EH Scott is an example).

[init4fun]

Originally Posted by decojoe67

Interesting. I didn't realize how dangerous these little sets could be! Likely these were used in kitchens very often. The novice electronics guy I am, I was poking in the chassis like a toy while it was on! eeeek!

As long as you don't pass the current from one arm to the other (or an arm to a leg , or any other path that puts the current flow across the chest to affect the heart) most 110 volt shocks are harmless . Now if the current path IS arm to arm or any other "heart path" it can take as little as 100 milliamps to kill if someone has a weak heart or an unlucky day . That's the basis of the "one hand in your pocket" rule when working on any energized equipment , avoid the heart path and avoid the date with the grim reaper .

As to the fuses/circuit breakers mentioned by the previous poster ;

Where it takes milliamps to kill , and somewhat over 15 amps to blow a branch circuit fuse( or trip a breaker) , HELL is gonna freeze over and get warm again before any fuse ever blows if someone finds themselves across the line as part of the circuit . Fuses/circuit breakers protect buildings from fires (sometimes) and are NOT there to protect people from their own mistakes with electricity , that's more the realm of things like GFCI and AFCI devices .

PS , whenever servicing any "hot chassis" device the smart technician always employs an "Isolation transformer" to remove the ground referenced neutral line from the circuit . This eliminates any possibility of coming between the difference of potential that may otherwise exist between the hot chassis and any other nearby grounded metal that could be touched .

[MadMan]

Originally Posted by init4fun

As long as you don't pass the current from one arm to the other (or an arm to a leg , or any other path that puts the current flow across the chest to affect the heart) most 110 volt shocks are harmless . Now if the current path IS arm to arm or any other "heart path" it can take as little as 100 milliamps to kill if someone has a weak heart or an unlucky day . That's the basis of the "one hand in your pocket" rule when working on any energized equipment , avoid the heart path and avoid the date with the grim reaper .

Say it takes 100mA to kill, the thing about that is, that 100mA has to go through your heart. Most of the current flows through your skin, not your insides. I've been zapped with 120v arm to arm so many times I couldn't count. Also, time is also a factor. Getting shocked for a second is very different from a scenario where you can't let go and get shocked for a minute or more.

Of course we're also talking about high DC voltages as well as 120VAC... and capacitors that can discharge large amount of current in one go. There's a lot of different factors at play, but of course, the one hand in your pocket rule is always wise.

[Electronic M]

AC disrupts nerve signals making it harder to let go, and also scrambles the heart signal effectively stopping pulse while current is flowing....DC resets the heart beat (like a one shot sync pulse) but doesn't stop heart function (unless you have a heart condition or you have such rediculous current flowing through that it is cooking you alive). Defibrillators basically are a single pulse DC source intended to resync an unstable pulmonary oscillator...

[dieseljeep]

Originally Posted by decojoe67

Interesting. I didn't realize how dangerous these little sets could be! Likely these were used in kitchens very often. The novice electronics guy I am, I was poking in the chassis like a toy while it was on! eeeek!

Actually those sets were designed properly. They used a floating B- line, which is not connected to the metal cabinet. It does use an isolating capacitor from the B- to the cabinet and the antenna coil.
BTW, the two and three tube sets are a TRF, where the four tube is a short superhet, which is a good DX machine with about 100 feet of antenna.

[decojoe67]

Originally Posted by dieseljeep

Actually those sets were designed properly. They used a floating B- line, which is not connected to the metal cabinet. It does use an isolating capacitor from the B- to the cabinet and the antenna coil.
BTW, the two and three tube sets are a TRF, where the four tube is a short superhet, which is a good DX machine with about 100 feet of antenna.

Right now I get a slight garble in the audio and I don't receive anything on the dial except for pumping in a signal from my AM transmitter. I have located the one rare tube and the other common one, so I am excited to see if that's the culprit. I heard the rare one, the 20B8GT, is not uncommon to find weak or dead.

[jr_tech]

Has it been re-capped and resistor checked?

jr

[decojoe67]

Originally Posted by jr_tech

Has it been re-capped and resistor checked?

jr

Yes. I had the members on ARF look at pics and they gave it the okay. My repair thinks it might be the tube/tubes. The rare one isn't known to be a particularly hearty tube. As-is is passable, but I hope The new tubes will step it up a notch.