From: sfjssa@nospam.com   
      
   I have a Ballantine 345 VTVM that uses a CVT for the PS.   
   This is a mid sixties, early 70's high accuracy laboratory VTVM, I obtained   
   via surplus vendor.   
      
   Upon power up, the transformer and the tank ckt cap (.8uf 660VAC motor run   
   cap oil) slowly began to heat and the excitation current increased beyond   
   design limits.   
      
   I was unable to source a .8 uf cap, and replaced it with a 1uf cap.   
   I also replace the other electrolytics in the PS.   
      
   I performed the calibration procedures as per the Ballantine instructions   
   and the meter performs all functions within tolerance spec. In fact this is   
   a very accurate device, measuring less than 1 ohm, or say 25 mv AC RMS. A   
   superb instrument in all respects. The meter movement is very steady and   
   locks on with no drift, even with a variation in line current, which I seem   
   to be suffering with here in SE Mass, shifts of +-4 volts are not uncommon   
   on my line, maybe due to the boat yard (heavy current consumption) down the   
   street, at "the end of the line". We are in a beach community with a lot of   
   salt spray.   
      
   The only issue now is it does still slowly get hot, the transformer   
   laminates have reached 145 degrees F after three hours of operation, then I   
   shut it down.   
   I have also noted the positive supply voltage to be 58 vs 62 volts.   
      
   I suspect the cap, but have been unable to source any info concerning   
   formulae for these CVT ferro transformers.   
      
   RDH has NO info at all, neither does any of the 25 or so engineering texts I   
   have address the CVT.   
      
   Is the 1 uf cap in the tank ckt causing an improper loading condition?   
      
   I suspect so, as they are very frequency sensitve, will the .2uf difference   
   be that influential?   
      
   I don't see any initial excitation current upon power up, just a slow   
   increase ratio with temperature.   
      
   TIA for any help, in the mean time I am trying to source an .8 uf 660 VAC   
   cap for the unit.   
      
   Regards,   
      
   Vin   
      
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