EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: Steve Wayne on May 09, 2015, 11:49:31 pm
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I picked up this meter recently and can’t identify the make & model. The ID plate has been removed. Anybody know what it is? It's a heavy bastard with tube circuitry. I was told that in it's day, it was extremely accurate.
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Um... just out of curiosity, what are you trying to accomplish by adding "LOOK>" to the end of the subject...?
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I'd guess a VTVM made for military use. It's fairly unusual to see a round meter face on a VTVM.
Take a picture of the insides and post it. You might find a clue inside when you do that.
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I'm guessing military. I believe that face plate was added later. it covers up some of the words on the meter.
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US Military VTVM, model A/N USM-116
Operating and repair manual at http://bama.edebris.com/download/military/an-usm116/usm116.pdf (http://bama.edebris.com/download/military/an-usm116/usm116.pdf)
I should add that in the 1950's and '60's the US Government took the position that it could buy equipment from HP or Tektronix and then put out a bid that (in the US Government's view) permitted other companies to duplicate the HP or Tektronix equipment, without regard for patents held by the original manufacturer. From what I can see, the USM-116 is a US Government contractor knock off of an HP410 VTVM.
Tektronix ultimately sued the US Government and several of the knock-off contractors for millions of dollars in patent claims for this practice and eventually (10 years or so) won.
Please note that in many cases, the cloned knockoffs did not not work nearly as well as the original HP or Tektronix designs because there was a great deal of non-patented and non-obvious design, component specification, calibration procedure, etc., that separated a real HP or Tek instrument from the low bid knockoffs. Some clone manufacturers did much better jobs than others in duplicating the original manufacturer's level of performance.