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Recent content by Willard

  1. W

    Lab Volt Model 790A will not power up

    Okay, it's official. To everyone who has taken time out of their own lives to help a person that they don't know, well this is for you. YOU GUYS ROCK! It looks to me like this is what I should be seeing. I replaced the oil film capacitors with PP capacitors. These are in the large red...
  2. W

    Lab Volt Model 790A will not power up

    Thanks!
  3. W

    Lab Volt Model 790A will not power up

    Edd. The test of the C18 capacitor failed so I replaced C16, C17, and C18. I then tested C18 again and man what a difference. There was a slight jump on the meter going across the newly replaced R51 resistor and then it zeroed out. I powered down and shorted out the new capacitors and they...
  4. W

    Lab Volt Model 790A will not power up

    Update. I soldered my new carbon film 1/2 watt 100K resistor in place of the toasted R51. I left the lead at A' flying and connected it to A which runs to the HV D5 diode. I then clipped my meter leads across the resistor and powered it up. I got no meter reading at that time so I installed...
  5. W

    Lab Volt Model 790A will not power up

    I just received my 1/2 watt carbon film resistors. I am assuming the new resistors are a lot smaller than the original burnt R51. I purchased the 1/2 Watt carbon film resistors with a 100K ohm rating.
  6. W

    Lab Volt Model 790A will not power up

    I received my 1 and 10 M resistors. They are both withing 5% To recap what I have done earlier. I checked for voltage at C16-17-18. None found. R51 ohm reading is OL or open lead. R51 has no continuity. I unsoldered A prime end of R51 and checked for ohm reading. It is still OL or open lead...
  7. W

    Lab Volt Model 790A will not power up

    Thanks Edd. I'll study this tonight. I have resistors coming in from Digikey on Thursday sometime so I will get back to you then with the appropriate readings. As always your help is appreciated! And seriously I have 12.5 gallons on honey. A diabetic has no use for that much liquid gold.
  8. W

    Lab Volt Model 790A will not power up

    I wish I could go to Radio Shack. That is where I used to get all of my few components when I needed them. Unfortunately the company went out of business and the stores were closed. I have two different kinds of electrical friends. The local guys who work on mains voltages and then the...
  9. W

    Lab Volt Model 790A will not power up

    It looks like I am going to have to order some resistors for the voltage divider. I have gotten on digikey and working on finding an acceptable resistor. My question is what are they made of? I can't tell by looking at the pictures. I am assuming they are either a carbon film or a...
  10. W

    Lab Volt Model 790A will not power up

    Scratch the previous question about reassembly. I went ahead and soldered the board grounds back to the chassis like it was before I entered into this journey. So to reiterate what I have done before. I checked for voltage at C16-17-18. None found. R51 ohm reading is OL or open lead. R51 has...
  11. W

    Lab Volt Model 790A will not power up

    I checked for voltage at C16-17-18. None found. R51 ohm reading is OL or open lead. R51 has no continuity. I unsoldered A prime end of R51 and checked for ohm reading. It is still OL or open lead. I have the blue lead that was connected to the A prime junction unsoldered and am now ready to...
  12. W

    Lab Volt Model 790A will not power up

    Wow! I'm on read through number 5 trying to take all this in. When this is all over I believe I will owe you guys big time. Which is okay if you like honey. I happen to have about 12.5 gallons of the stuff. Message me with your address and I'll get some moving your way if you want. The...
  13. W

    Lab Volt Model 790A will not power up

    Thanks much. I'll check it out and practice tonight. Will
  14. W

    Lab Volt Model 790A will not power up

    Will do. My problems is not knowing that these are polypropylene capacitors rather than electrolytic or some other type. Also Axial termination style. I could get the Volts and the MFDs but I wasn't sure about the capacitance. I am assuming the oil capacitors that are in there aren't made...
  15. W

    Lab Volt Model 790A will not power up

    Would you, by chance, have a suggestion for the blue 1600WV .1 MFD capacitor? I looked up the parts you suggested on Digikey and there are way too many options for me to choose from. I'm simply not well versed enough to know which one is would work.
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