From: noone@nospam.com   
      
   On 21/4/2017 1:56 μμ, Diesel wrote:   
   > Tzortzakakis Dimitrios    
   > news:oc88v5$8p2$1@dont-email.me Fri, 07 Apr 2017 14:53:06 GMT in   
   > alt.engineering.electrical, wrote:   
   >   
   >> A client left a faulty microwave oven at my friend's shop, I   
   >> opened it up and first thing I checked was, of course the HV fuse.   
   >> It was open so a new one. Nothing. Checked with my HV probe, at   
   >> the transformator secondary 3.5 kV(AC). At the magnetron nothing,   
   >> no DC at all. Thought it was the HV capacitor or the HV diode.Took   
   >> them home, measured the capacitor with my capacitance meter, 1 μF   
   >> ok. Checked with my insulation tester that can put up to 1000   
   >> volts, the diode, forward bias 0 Ω, reverse bias >10 ΜΩ ok.Of   
   >> course I didn't do anything as when you repair household   
   >> appliances you must be absolutely sure you'll repair it, there's   
   >> no room for experiments.Anyone with a brainwave? Again, the trafo   
   >> AC ok, DC nothing-something wrong with the magnetron?   
   >   
   > What is the make/model of the meter you've mated the HV probe with to   
   > test the voltage coming off the transformer?   
   >   
   >   
   It's the Benning MM-1. A very good one, I think. I think I followed the   
   correct procedure or I wouldn't be here talking to you:-) The HV probe's   
   division factor is 1000, that means that 3.5 kV will appear in the   
   multimeter as 3.5 volts. The probe's manual says never to choose auto   
   range, and make sure that the input impendance of the multimeter must be   
   at least 10 MΩ. If the input impendance is 1 MΩ, then it's 2000.That   
   means 1 kV becomes 0.5 volts. I don't know the input impendance of my   
   multimeter, I did a google search obviously which turned out nothing. I   
   have tested the HV probe measuring line voltage 0.22 kV ok.   
      
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