Here in 2023 the field of electronics covers a breathtaking variety of devices and applications, but if we were to go back in time far enough we’d enter an age in which computers were few and far between, and any automated control systems would have been electromechanical at best. Back in the 1950s the semiconductor industry was in relative infancy, and at the consumer end electronics were largely synonymous with radio. [Shango066] brings us a transistor radio from that era, a Jewel TR1 from about 1958, that despite its four-transistor simplicity to our eyes would have been a rare and expensive device when new.
As you’d expect, a transistor radio heading toward its 70th birthday requires a little care to return to its former glory, and while this one is very quiet it does at least work after a fashion. The video below the break is a long one that you might wish to watch at double speed, but it takes us through the now-rare skill of fault-finding and aligning an AM radio receiver. First up are a set of very tired electrolytic capacitors whose replacement restores the volume, and then it’s clear from the lack of stations that the set has a problem at the RF end. We’re treated to the full process of aligning a superhet receiver through the relatively forgiving low-frequency medium of a medium-wave radio. Along the way, he damages one of the IF transformers and has to replace it with a modern equivalent, which we would have concealed under the can from the original.
The video may be long, but it’s worth a look for the vintage parts if not for the quality of radio stations on the air today in California. For many readers, AM broadcast is becoming a thing of the past, so we’re not sure we’ll see this very often.
I love Shango’s videos, especially the TV resurrections. I highly recommend watching a few, if you have any interest in real diagnosis and repair.
I agree, he really seems to know what he’s doing with the old stuff.
Transistor radios are hard to find these days. Only found a couple Sony AM/FM radios in recent years. Still an AM listener since the 70’s. Good to see someone giving them new life instead of tossing them in the trash.
I’m surprised the germanium transistors haven’t gone leaky by now. I have on old Transoceanic with plug-in transistors, some are soft. Also a leather clad Zenith AM only low volume, on only locals.
This radio is so first gen with transformers both in output but inter-stage as well. Single ended output no less.
I remember looking at portable radios at our local e-store in ’67 or ’68 and the salesman explaining from behind the glass counter “that all the best radios have genuine leather cases”. It was still a thing 10 years later, only then did plastic win.
Careful with those matches, close cover first with those front strikers.
“Leaking” is not really a problem with transistors (but with capacitors, of course). Some transistors were just filled with air, others with a kind of gel. Leaking or not, they keeped on working. But some of them are prone to the notorious tin whiskers:
https://nepp.nasa.gov/whisker/anecdote/af114-transistor/index.html
+1
I was going to say that. These growing “hairs” are what made those ‘ancient German(ium)s’ do fail here.
Interestingly, these defects do not necessarily break their DC operation entirely. So if inserted in a transistor tester, they may appear to be working still. However, they no longer work for RF.
Some half-broken capacitors can act similar, I think. They may seem to be okay at first, but fail in RF applications.
Btw, it’s possible to temporarily fix these Germanium transistors by “shocking” them (metal can types). Doing so burns away these fine “hairs”. Unfortunately, they may grow back over time.
It was one of the first instructions given to me as a radio apprentice….tap the transistor metal case to see if the radio burst into life!
I have done a few restorations of some old transistor radios…the last one being one of the first BUSH portable transistor radios produced in the UK. Several transistors had developed short circuits inside their metal cans due to the “spurs” that grow inside. I discovered how to clean the tuning capacitor using the dish washer on a short cycle and then re lube ing the bearings.
Here in Central Europe “the lack of stations” has a simpler cause: the lack of stations ;-) AM / SW now pretty much is how we imagined the day after a nuclear war, back in the ’70s: blank radio bands, just hiss and white noise.
“Central Europe”.. Is that what used to be called “Western Europe” during cold war (up to the 90s)? You know, France, Germany, Belgium, Swiss, Austria etc..
Transistor radios used to be almost universally marketed based upon the number of transistors they had, based upon the impression that more was better. I spent my career at a large U.S. semiconductor company, and in the early 70’s we had a LOT of Chinese radio manufacturers buying our test rejects (opens, shorts) to stuff their radios to bump up the transistor count. We literally sold them by the pound, although eventually we got religion and stopped selling known rejects. I imagine that troubleshooting some of those radios could be initially confusing.
That’s cool! My father once told me about the existence of transistor “sockets”. Similar like to tube sockets, because transistors were very pricey in the beginning. So they weren’t soldered in, but stuck in a socket..
part of the transistor socket ‘plague’ resulted from the claim that soldering heat would unsolder the ‘bonding wires’ inside the can.
On some transistor radios it was easy to spot the fakes, all three leads were soldered into the same hole.
Or 3 xsistors glued side by side to the PCB.
You like that, you should see Mr. Carlson’s Lab. https://www.youtube.com/@MrCarlsonsLab
Germanium transistors can’t stand temperatures as high as silicon can. It needn’t melt for the heat of soldering to alter the doping profile.
Your article reminds me back in time, I remember during those days of my curiosity on radios especially tuning those trimmers and padders,the ift’s and the oscillators just to find the clearest and best receptions ,only to find out that there’s a procedure for these adjustment s, 😕😕
Once you replace all the loe quslitu electrolytics with wualitu chinrse capscitors anf replace the rubbush af117 transistors you will have a radio that id soon to be udeless junk ad the nedium and longwave transmitters are closeing down a lot if vintage radio sets tobe sent to tje tip soon