[time-nuts] Wenzel Oscillator Repair (plus Tektronix CG551/CG5001/DC509/DC5009)

[Mark Sims]

Interesting...  I just fixed a couple of Tek CG551 and 5001 calibration generators that had the same problem.  Tek uses a DC isolated shift register chain to drive the internal control signals.  The clock and  data lines run through toroidal pulse transformers that are mounted on small plastic carriers.  Turns out that the where the toroid leads are attached to the carrier leads they were broken.  The toroids are not pookied down to the carrier.  

And,   by the way,  if you have a DC509 or DC5009 counter that is displaying error 320,  the problem is most likely a ruptured Q1401 transistor on the gate line.  I fixed half a dozen of these things (all from different sources)  with the exact same problem...  magic smoke got out of the package...

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The problem with the oscillator turned out to be even easier to fix than 
I could have hoped for.  There's a ferrite transformer on the output - 
possibly a balun.  The wire is about the thickness of a hair.  The 
ferrite isn't tied down - it's just held by the leads. 
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