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How to revive a first generation Olympic 447 portable transistor radio

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**this instructable assumes that you have basic electronics knowledge, you can solder, and you have the ability to use basic hand tools.**

in this instructable we'll be covering the basic rebuild of an early portable transistor radio. these big transistor radios where called "lunchbox radios" and were how folks took their entertainment outdoors 50+ years ago. some folks called them camp radios.

portable radios were not a new idea but transistor technology meant your batteries could now last a year or so instead of a few hours like they did with tube portables. eventually the big lunchbox sized AM only radios fell out of favor and were replaced by shirt pocket AM radios that weren't much bigger than our current cellphones.

when it comes to first generation transistor radios, the olympic 447 is in a league all it's own. let's say your a radio manufacturer in the 1950's but not one of the big boys. you're anxious to get on the transistor radio bandwagon but don't have the R&D budget that the big boys have. what to do?

you take one of your current vacuum tube radios, have your engineers redesign the circuit, and shove the transistor leads right down the same sockets the tubes used to plug into! that's what the 1956 olympic 447 is all about.

using only 4 transistors in a circuit that used to be setup for 4 tubes, this early transistor radio performs quite well despite it's low transistor count. the big ferrite antenna helps it pull in stations much better than the 4 transistor sylvania reflex radio i have in a different instructable. power was furnished by (2) 9V brick style batteries. in a radio like this, batteries of that size would easily last over a year with daily use.

ok, enough history, let's see whats inside.

 
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longwinters7 months ago
If you find a "weird" battery save it, they almost always are thrown out, it's quite hard to find old ones for display, obviously they are quite dead, if you don't believe me try finding old batteries in junk and antique shops
Great instructable btw
janbeee210 months ago
I will likely never do this instructable, but I appreciate so much the knowledge gained from reading it. Thanks!
terryatsbe10 months ago

So good to see a technically correct article on the internet... from an
EE perspective I see so much junk tech! Excellent photography, too.
I also have a 447, along with a lot of other period transistor radios. Most
have issues related to age, particularly IF transformers. My 447, after
"repairs" rather than restoration, performed as well as any 4 transistor set
I ever had. This an excellent design, not at all a "tube design altered for
transistors and hurried into production. Jeeese, but such an ugly cabinet.
[reasonable people may reasonably disagree :>) ] I also use the radios I accumulate, mostly for baseball games in the summer.
Last time I used the 447, alas, it became noisy, volume jumping around,
then "local stations only" Usually old IF transformer disease. Often the pressure
contact mica resonating capacitors get intermittent. Luckily, the IF cans in
these are large enough so repairs may be possible.

Keep up the great work!

Terry
CYberUg10 months ago
kewl
Pro

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