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Barry H Bennett
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Post subject: A Small Doodad Whatizzit Posted: Sep Sun 15, 2019 3:14 pm |
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Joined: Nov Wed 30, 2016 7:35 pm Posts: 9323 Location: Sunbury, Ohio 43074
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Found this little home brew box in a pile of stuff. I understand the BNC to binding post adapter, and the hot to ground reversal switch. I don't understand the 330K resistor... anyone venture a guess as to what the builder intended here ?? I suppose maybe a high to low impedance converter (or the reverse) of sorts... but as crude as this implementation of such a device as this one is ... what was it supposed to be used for ? Attachment:
fullsizeoutput_890.jpeg [ 106.34 KiB | Viewed 1632 times ]
_________________ Preserving the hist. of electronics, one boat anchor at a time! :) https://www.bbtvtestequipment.com
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Conrad Hoffman
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Post subject: Re: A Small Doodad Whatizzit Posted: Sep Sun 15, 2019 3:21 pm |
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Joined: Jun Sun 23, 2013 9:03 pm Posts: 493 Location: Canandaigua, NY
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It's the sort of thing you might use with a sensitive galvo or other detector to eliminate polarity errors, but there's never a way to short out the 330k for full sensitivity. Something audio for getting minimum hum, but again, the 330k seems high.
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wazz
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Post subject: Re: A Small Doodad Whatizzit Posted: Sep Sun 15, 2019 6:35 pm |
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Joined: Jun Wed 08, 2011 2:33 am Posts: 11521 Location: Ohio 45177
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With no context and no labels, it is an inscrutable mystery. What other sorts of things were associated with it in the group, if anything?
_________________ Reddy Kilowatt says; You smell smoke? Sorry about that!
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bob91343
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Post subject: Re: A Small Doodad Whatizzit Posted: Sep Sun 15, 2019 6:42 pm |
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Joined: Jan Tue 10, 2012 8:39 am Posts: 2103
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No telling if the binding posts were the output or the input, likewise the BNC. And the unused binding post was grounded.
It's also possible that the builder was trying out an idea that turned out not to work.
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majoco
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Post subject: Re: A Small Doodad Whatizzit Posted: Sep Sun 15, 2019 9:20 pm |
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Joined: Mar Mon 17, 2008 5:05 am Posts: 5494 Location: Ashhurst, New Zealand
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Quote: It's also possible that the builder was trying out an idea that turned out not to work. I've got some of those too..... 
_________________ Cheers - Martin ZL2MC
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Barry H Bennett
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Post subject: Re: A Small Doodad Whatizzit Posted: Sep Mon 16, 2019 11:15 am |
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Joined: Nov Wed 30, 2016 7:35 pm Posts: 9323 Location: Sunbury, Ohio 43074
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[quote]What other sorts of things were associated with it in the group, if anything?/quote] It was in an auction flat with "other things"  I'm afraid it's true purpose shall be forever lost to history. I may just remove the resistor and use it as a BNC to banana converter. It's in a nice little shielded box about 1"x1/2"x1/2"
_________________ Preserving the hist. of electronics, one boat anchor at a time! :) https://www.bbtvtestequipment.com
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Chas
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Post subject: Re: A Small Doodad Whatizzit Posted: Sep Mon 16, 2019 2:54 pm |
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Joined: Jan Thu 01, 1970 1:00 am Posts: 15529 Location: S. Dartmouth MA 02748-1225 USA
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An input adapter, where the coax (signal) is in/out to an instrument/radio or RF source is parallel. I made such a device for a Hammarlund SP-110x radio to "flip" the antenna which was coax to either side of the two terminal antenna input for the radio. The antenna was only partially resonant so the shield of the coax was ,on certain bands, picking up signal. I would not know the signal was there unless I flipped the switch. My circuit was deLux  I also included a ground selector switch. Crazy? No, it worked and it is still attached to the radio via the terminal screws, I don't like permanent mods to a boatanchor. It was my first experiment with printed circuit. I had a pal that worked at the local printed circuit factory, I got scrap board and some etchant. Mil spec fiber glass, tough as nails board too... Chas
_________________ List' & I will Enchant Thine Ear
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wazz
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Post subject: Re: A Small Doodad Whatizzit Posted: Sep Mon 16, 2019 3:05 pm |
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Joined: Jun Wed 08, 2011 2:33 am Posts: 11521 Location: Ohio 45177
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We locally manufactured some stuff like that at work. Without any labels or context they would be a total mystery to anyone and so specialized that even if you knew you could not use it for much else. They are for parts, or what you can make of them.
_________________ Reddy Kilowatt says; You smell smoke? Sorry about that!
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flyboy71
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Post subject: Re: A Small Doodad Whatizzit Posted: Sep Mon 16, 2019 3:13 pm |
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Joined: Mar Wed 11, 2015 1:46 am Posts: 1369 Location: Boiling Springs, PA
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VolkerK
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Post subject: Re: A Small Doodad Whatizzit Posted: Sep Mon 16, 2019 5:41 pm |
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Joined: Dec Sat 17, 2011 5:53 pm Posts: 92 Location: Lee, MA 01238
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My best guess about the resistor... It prevents a short in case the switch makes contact between 1 and 2 when switching position. I would check for a short between 1 and 2 when switching before removing the resistor. Why 330k? No idea.
_________________ Wer misst, misst Mist. http://www.oscilloscopemuseum.com
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Barry H Bennett
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Post subject: Re: A Small Doodad Whatizzit Posted: Sep Mon 16, 2019 10:26 pm |
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Joined: Nov Wed 30, 2016 7:35 pm Posts: 9323 Location: Sunbury, Ohio 43074
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flyboy71 wrote: It appears to be an early component from a Turbo Encabulator That's a relief. I was thinking it might have been a DiLithium Crystal Degenerator .........
_________________ Preserving the hist. of electronics, one boat anchor at a time! :) https://www.bbtvtestequipment.com
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W8ZV
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Post subject: Re: A Small Doodad Whatizzit Posted: Sep Mon 23, 2019 1:11 pm |
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Joined: Feb Mon 04, 2008 3:20 am Posts: 1204 Location: Coopersville, MI 49404-9643
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flyboy71 wrote: It appears to be an early component from a Turbo Encabulator Personally I think that it's the input network for a Heisenberg compensater.
_________________ Kim Herron
W8ZV
kim.herron@sbcglobal.net
616-677-3706
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radiotechnician
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Post subject: Re: A Small Doodad Whatizzit Posted: Sep Wed 25, 2019 9:47 am |
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Joined: Sep Thu 23, 2010 6:37 am Posts: 12437 Location: Powell River BC Canada
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For testing a stereo amp. Feed signal to left input with right channel input grounded.
Then the other way.
_________________ de VE7ASO VE7ZSO Amateur Radio Literacy Club. May we help you read better. Steve Dow ve7aso@rac.ca
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[ 13 posts ] |
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