EEVblog Electronics Community Forum
General => General Technical Chat => Topic started by: Steve Wayne on May 05, 2015, 02:35:40 am
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Just for show & share,, I thought this old (mid 1960's?) Harman Kardon SR-900 receiver was quite amazing to find it with no circuit boards and all through hole, hand soldered components. I'm sure Dave would have enjoyed the smell, but it would cost a small fortune to ship it from the US. Take a look…
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It's called point-to-point wiring and it's the way everything used to be done. And if you think that's a hornet's nest, take a look at a typical TV set:
(http://antiqueradio.org/art/WestinghouseH-181UndersideOriginal.jpg)
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Shame, looks like someone pulled all the (socketed!) RF transistors. Probably 2N3904 would work (unless they were PNP, which might well be the case if they used mesa germanium).
Seems unlikely those perfboards on the top controls are original, kind of curious what history it might have.
And yes, boys and girls, early transistor sets used output transformers to drive the speakers!
Tim
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Some radio amateurs carry on a similar tradition in home construction, they call it 'ugly' construction. Tag strips are now difficult to obtain so if you have a junction suspended in mid air then solder a 1M ohm resistor from the junction to the PCB ground plane, it works just fine.
http://www.k4gc.com/ugly%20things.html (http://www.k4gc.com/ugly%20things.html)
I prefer a technique called 'Manhattan' where small PCB pads are glued down to support parts
http://www.k8iqy.com/qrprigs/2n215/2n215081e.jpg (http://www.k8iqy.com/qrprigs/2n215/2n215081e.jpg)
http://www.k8iqy.com/qrprigs/2n240/2n240216.jpg (http://www.k8iqy.com/qrprigs/2n240/2n240216.jpg)
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Alan Wolke (w2aew on the forum) has some good videos on construction techniques including Manhattan-style and island cutting, particularly this excellent summary:
https://www.youtube.com/watch?v=kH110yjYZ2g#ws (https://www.youtube.com/watch?v=kH110yjYZ2g#ws)
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Some radio amateurs carry on a similar tradition in home construction, they call it 'ugly' construction. Tag strips are now difficult to obtain to if you have a junction suspended in mid air then solder a 1M ohm resistor from the junction to the PCB ground plane, it works just fine.
Standard way of doing it these days is with eyelet or turret boards. I always thought tag strips were turret board's ugly, annoying sister, anyway.
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I prefer a technique called 'Manhattan' where small PCB pads are glued down to support parts
http://www.k8iqy.com/qrprigs/2n215/2n215081e.jpg (http://www.k8iqy.com/qrprigs/2n215/2n215081e.jpg)
http://www.k8iqy.com/qrprigs/2n240/2n240216.jpg (http://www.k8iqy.com/qrprigs/2n240/2n240216.jpg)
This isn't ugly at all. It looks like a work of art. :D I knew there has to be a way to prototype RF.
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Manhattan works very well at RF. There is one amateur who works as an engineer at the VLA in New Mexico and he uses Manhattan PCBs well beyond 1 GHz. The large ground plane means a stable circuit.
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I prefer a technique called 'Manhattan' where small PCB pads are glued down to support parts
http://www.k8iqy.com/qrprigs/2n215/2n215081e.jpg (http://www.k8iqy.com/qrprigs/2n215/2n215081e.jpg)
http://www.k8iqy.com/qrprigs/2n240/2n240216.jpg (http://www.k8iqy.com/qrprigs/2n240/2n240216.jpg)
This isn't ugly at all. It looks like a work of art. :D I knew there has to be a way to prototype RF.
It's also translucent, http://seventransistorlabs.com/Images/Glow.jpg (http://seventransistorlabs.com/Images/Glow.jpg)
Tim