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Author Topic: Benrus RA850 Oscilloscope. Has anyone ever seen this kind?  (Read 1988 times)
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Opcom
Patrick J. / KD5OEI
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« on: March 31, 2019, 01:32:59 AM »

So this is one of the old scopes I picked up for some $5 or so.

Turns out the RA850 was Manufactured by Benrus Technical Products Division, A subsidiary of Benrus Watch Company, Inc. Information is scarce. Benrus aso made a few other electronic instruments as found in electronics magazines, but no catalog or manuals seem to be online and I have never seen one of these in 50+ years. Benrus seems best known for watches.

It seems to have been part of a test set or analyzer. There are tapped holes around the front as if to panel-mount it, and also three tapped holes in the rear cabinet face for same, and the power and signal input connector is in the rear as well. It appears to be basic, with the X, Y amplifiers and power supplies. The sweep and deflection seem to have come from elsewhere. The power transformer is missing and the markings are gone from the CRT. Not a show stopper but an obstacle for sure.

I know this is dirty/ugly but so are a lot of radios.
Might be a decent mod scope if made to light up.

Has anyone a schematic or information for this or a similar Benrus oscilloscope?


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Radio Candelstein - Flagship Station of the NRK Radio Network.
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« Reply #1 on: March 31, 2019, 09:09:17 AM »

interesting scope...modular vert and horiz amps etc....looks like there is a transformer missing....  good luck
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« Reply #2 on: March 31, 2019, 06:20:20 PM »


Bottom of the graticle says "kHZ"... looks like the display part of another instrument.

What does the power connector/input look like?
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_-_- bear WB2GCR                   http://www.bearlabs.com
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« Reply #3 on: March 31, 2019, 10:55:49 PM »

Vertical axis decibels, horizontal kHz....that is the display for a spectrum analyzer!!
Probably integrated into a system by Watkins-Johnson, CEI, E-Systems or Submarine Signal.  Probably never offered for commercial sale.  The shadow where the power transformer once lived, looks a bit small....perhaps a 400Hz power transformer for airborne application ?

-Chuck K7MCG
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Opcom
Patrick J. / KD5OEI
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« Reply #4 on: April 01, 2019, 11:50:09 PM »

Here's the power and input connector. Nice old style. There is a metal shell which is loose, not shown but typical for this kind of plug.

Could be a missing 400Hz transformer, hard to say. Black face leans toward airborne use, but just speculation. If I had the diagrams, might be fun to see about firing it up. Bypassing the built in amps could yield a nice mod scope. It's like having a fancy glass dorknob. Just need the rest of the house.

Benrus being a watchmaker.. scopeclock comes to mind but there could be better uses. I could get by just knowing the CRT type.


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