EEVblog Electronics Community Forum
General => General Technical Chat => Topic started by: williefleete on February 14, 2011, 06:11:24 am
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a while ago when i was going through a phase of collecting boxes of random stuff off trademe i have picked up one or two bits of old test gear
the most interesting of which is a 70's era transistor tester from BK precision using in itself transistors, 74 series logic and a few op amps.
originally it ran off 117 volts AC, however i had swapped the transformer out for a 240 volt one and more recently modified it to operate from 6 double A batteries replacing the neon with an LED, as it needs split rail each side needing ~4.5 - 5 volts. its handy for determining the pinouts of a particular transistor and whether said transistor is functional, using the rotary switch under the meter will measure leakage current and identify whether its germanium or silicon (i actually had a germanium transistor floating around and it did indeed identify it as a PNP germanium and the leakage current was within the germanium signal realms of the meter too) most modern transistors measured on the unit identify as silicon and have almost zero leakage unless a damaged one is put in then it just pegs the meter. with a functional transistor it emits a tone and lights the LED indicating which type of transistor it is.
by the looks of things you can get banana probes for in circuit measurement however when i got the unit they werent supplied
(http://img843.imageshack.us/img843/7092/aut5358.jpg)
(http://img703.imageshack.us/img703/9166/aut5359.jpg)
(http://img69.imageshack.us/img69/9954/aut5360.jpg)
(http://img195.imageshack.us/img195/2820/aut5361.jpg)
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This is one of my great finds...a telco network analyzer at Goodwill (a thrift store) for $8. Man, I wish I'd known about these sooner! It's essentially a sine wave generator and wideband AC voltmeter reading out in dB in the same box. Set the frequency and level on the output side, flip the switch and read the results on the input side. Awesome for characterizing a filter shape or seeing the effects on signal conditioning on your analog data.
I think it was so cheap because it's designed for field use and the power cord tucks away behind a false back panel. They probably couldn't find the power cord so they couldn't even get it to light up. Works perfectly and agrees with my Fluke benchtop meter for frequency response and dB levels, although I'm not certain just what the 0 dB reference point corresponds to.
(http://digital-diy.com/forum/download/file.php?id=939)
(http://digital-diy.com/forum/download/file.php?id=940)
(http://digital-diy.com/forum/download/file.php?id=941)
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Here is a piece of history. This is how you would measure milli-amperes before electronic meters were born.
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Here is the specs for the above instrument for those interested.
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Here's an old piece of test equipment i've used on occasion.
A magnetic current meter, you just position the cable you want to measure in the channel on the back and it reads the current from the magnetic field in the cable.
(http://psi.abcom.co.nz/magneticcurrent.jpg)
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Nice gear. One day I hope to have a lab full of this old type of gear to fulfil the whole crazy scientist look.
Modern gear is so boring looking.
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I've got a lot of old stuff, but this is probably the oldest.
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And then there's my favorite DMM. <grin>
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I've posted Weston Engineering Notes from 1946 and 1947 (http://www.clever4hire.com/throwawaypic/home/weston-engineering-notes). I have another year and a half to scan. I'm not sure if John's meter is pictured anywhere in the collection but a lot of similar meters are.
As far as I have been able to determine, Weston Instruments went though a series of mergers and acquisitions in the 70s and has disappeared in the process.
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And then there's my favorite DMM. <grin>
I had one of those when I was in college (early 70's). Got it at a place that got scrap from Western Electric. It was not the fastest, but worked great, until I sold it.
Paul
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And then there's my favorite DMM. <grin>
i'll bet. its got NIXIES!!!
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Just some stuff I have:
Tektronix 547
(http://i185.photobucket.com/albums/x5/excavatoree/Old%20Test%20Equipment/Tek547.jpg)
Simpson Roto Ranger (multiple scales rotate into place behind pointer)
(http://i185.photobucket.com/albums/x5/excavatoree/Old%20Test%20Equipment/RotoRangerVOM.jpg)
A "tube testing" version
(http://i185.photobucket.com/albums/x5/excavatoree/Old%20Test%20Equipment/RotoRangerTube.jpg)
Old Weston in wooden case (Needs cleaning!)
(http://i185.photobucket.com/albums/x5/excavatoree/Old%20Test%20Equipment/OldWeston.jpg)
Hickok 539C Tube Tester (So called "engineer's model, but the "FAA" tester is supposedly better.)
(http://i185.photobucket.com/albums/x5/excavatoree/Old%20Test%20Equipment/Hickok539C.jpg)
Hickok (I think it's a 501)
(http://i185.photobucket.com/albums/x5/excavatoree/Old%20Test%20Equipment/Hickok501.jpg)
Cornell Dubilier Capacitor Checker with "magic eye" tube
(http://i185.photobucket.com/albums/x5/excavatoree/Old%20Test%20Equipment/CD-CapChecker.jpg)
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:o :o
Simpson Roto Ranger (multiple scales rotate into place behind pointer)
(http://i185.photobucket.com/albums/x5/excavatoree/Old%20Test%20Equipment/RotoRangerVOM.jpg)
Old Weston in wooden case (Needs cleaning!)
(http://i185.photobucket.com/albums/x5/excavatoree/Old%20Test%20Equipment/OldWeston.jpg)
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i saw tons (literally) of that stuff at hamfest orlando & skycraft this past weekend. i should have snapped some photos, but i fail. :-\
-sj
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Here are some shots from my shop.
One of my Weston meters:
My Tek 547 was my first "real" scope. Still works and I used it regularly until a few years ago:
Here are a some additional Tek plug-ins for the 547:
Paul
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This meter has up to a 240 volt input.
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This meter can measure up to 600V DC to 135Hz. Note the mirror behind the indicator, this is to prevent parallax error when reading the scale.
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A pic of an interesting LCR meter, now where is the LCD!!.
John
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(https://gcna3g-bn1306.files.1drv.com/y3mIdWFTPf-MG6JrpWem0GSKfanBqn1kN6aPyuaPO3mPE4GWNIKD9IK1ewrFmAbYam_FKbsrZNL5h7paxa98sIvRQwCb_v0MxbBJuGqaL9gMVPcoZaSckATpnt8vtUq-JBqYGVc2WKA7anVtAmJ4l0eoeh7VXkFI_-ZG6KIlnWj_us?width=593&height=660&cropmode=none)
(https://gsna3g-bn1306.files.1drv.com/y3mZVeoh431h3S24n8_1iRmZUUZTpUFtIIjD4QY-qBl02pvnyHntGBtYhfJozo1iRWhrKE8O0Kx3U02mPyFUNO4y0pRrujgWVkg-FR-cFJ7pnymY6T-xWfPepTSWylJ_JhgnV3yHOBeTynE8X7gYZ28UyoMJI1efwAR-ouddliScZo?width=449&height=660&cropmode=none)
(https://hina3g-bn1306.files.1drv.com/y3mK0zB4-y9v5V3EMjRwFJMqXSMhKTOTffBHogEJAWpMgc-acoPOmTm9ZPKbLlw0lMF3EXBCZBCkd6HX-u0mlHF6w_lgH-HVvjoZvqtpH0i5d4OfU-kR0C4B5sYcOM1AIy2O2OudCyJqpI4dFqi5cYUXQLAnuzQgx7AaotcOC1Gvzo?width=1848&height=660&cropmode=none)