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Loose Radio Part?

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george w View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote george w Quote  Post ReplyReply Direct Link To This Post Posted: Jan/07/2022 at 3:38pm
The green circled parts are the power output transistors of the radio’s internal amplifier that power the speaker.
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JGRANTAMX View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote JGRANTAMX Quote  Post ReplyReply Direct Link To This Post Posted: Jan/08/2022 at 11:18am
There would be two output transistors for one speaker?

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Post Options Post Options   Thanks (0) Thanks(0)   Quote 6PakBee Quote  Post ReplyReply Direct Link To This Post Posted: Jan/08/2022 at 1:12pm
Originally posted by JGRANTAMX JGRANTAMX wrote:

There would be two output transistors for one speaker?

J


Could be a Darlington pair.

https://en.wikipedia.org/wiki/Darlington_transistor
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bigbad69 Quote  Post ReplyReply Direct Link To This Post Posted: Jan/08/2022 at 3:00pm
Could also be a push/pull configuration. Google "Class B amplifier" if you're curious.

BTW, after re-reading the OP more carefully, I realize the question was with regard to AM/FM radios. The picture I posted was of an AM radio. That may also explain the absence of the aforementioned clip in my radio. Apologies for going on a tangent...
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george w View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote george w Quote  Post ReplyReply Direct Link To This Post Posted: Jan/08/2022 at 3:05pm
If there are two transistors then the answer is yes, two transistors for one channel of amplification. This is the more typical and preferred amplifier output stage configuration called “ push-pull “. One transistor handles the positive going portion of the signal and the other transistor handles the negative portion. The transistors may or may not be of the same type or part number. A single transistor ( or tube ) output stage design is called “ single ended “ and was used very early on in solid state design or on very low cost amplifier designs. Push-pull design is the better choice and is always preferred. Early Delco transistorized radios used single ended design.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Steve_P Quote  Post ReplyReply Direct Link To This Post Posted: Jan/09/2022 at 8:44pm
68-70 AM used one transistor mounted on the RH side; AM/FM used two mounted on the front.  FWIW.  The transistors were also date coded.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bigbad69 Quote  Post ReplyReply Direct Link To This Post Posted: Jan/09/2022 at 9:48pm
Originally posted by Steve_P Steve_P wrote:

FWIW.  The transistors were also date coded.
All semiconductors are date coded, was back in the 60s, still is today- usually year and week.
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