Heathkit SB-200 HV Question

Discussion in '"Boat Anchor" & Classic Equipment' started by WB4YVO, Jul 30, 2020.

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  1. WB4YVO

    WB4YVO Ham Member QRZ Page

    AC input 120 Volts measuring draw of 900 Ma. AC.. This is with NO tubes.. I use a Fluke meter with a HV probe..5KV.. The probe and the meter on SB-200 are very close to each other .. Brand new Harbach Cap board.. So the metering resistors should be good..



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  2. WB4YVO

    WB4YVO Ham Member QRZ Page

    AC input 120 Volts measuring draw of 900 Ma. AC.. This is with NO TUBES.. I use a Fluke meter with a HV probe..5KV.. The probe and the meter on SB-200 are very close to each other .. Brand new Harbach Cap board.. So the metering resistors should be good..

    This is a SB-200 NOT a SB-220..

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  3. WA2CWA

    WA2CWA Ham Member QRZ Page

    When you say "recapped" (Harbach), are you really saying you replaced the old power supply board and parts with the Harbach board and parts, or are you saying you just replaced the caps with caps from Harbach?
    What I would do is disconnect the HV line from the rest of the circuit and measure the HV output right on the power supply board. If it's still 2000V, then it's something on the power supply board (bad solder joint, bad cap, bad diode, etc.). Typical HV DC output should be around 2400 volts.
     
  4. WA2CWA

    WA2CWA Ham Member QRZ Page

    I just saw you have the same topic posted in two different discussion groups. Posting the same topic on two different discussion groups on the same web site is never a good thing. Leads to confusion and discontinuity in responses. Let this thread die and just keep the other one going.
     
  5. W1QJ

    W1QJ Ham Member QRZ Page

    Your voltage is down about the same value that would be dropped across one filter cap. So you have a filter cap that could be internally open or way off in value. I had this happen to me once. A brand new cap was bad. No reading whatsoever on it when I measured the capacitance. Check everything carefully as you did build it.
     
    KD2ACO likes this.
  6. N2EY

    N2EY Premium Subscriber QRZ Page

    The SB-200 uses 572B tubes.

    There are only two choices with the SB-200: "120 volts" and "240 volts". Both are nominal voltages. There are no taps to adjust for lower or higher line voltages.

    73 de Jim, N2EY
     
    WQ4G likes this.
  7. WB4YVO

    WB4YVO Ham Member QRZ Page

    OK CLOSED
     
  8. KD2ACO

    KD2ACO Platinum Subscriber Platinum Subscriber Life Member QRZ Page

    Lou W1QJ came up with the most likely explanation in the Amplifers forum, that one of the HV caps is open or very low in capacitance. 400 volts is about the drop on each cap.
     
    N2EY likes this.
  9. N2EY

    N2EY Premium Subscriber QRZ Page

    ????
     
  10. WA2CWA

    WA2CWA Ham Member QRZ Page

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