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Dentron GLA1000b meter shunt resistor.

Discussion in 'Amateur Radio Amplifiers' started by W1UWC, Feb 12, 2019.

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  1. W1UWC

    W1UWC Ham Member QRZ Page

    Am restoring a Dentron GLA1000b have gotten new power supply board from FarCircuits. Have most of the components but R2. In the manual it gives all the values, except for R2 the meter shunt resistor. Anyone know what the value is? Appreciate any help. Have tried the Dentron group, but it appears the group is not active, have sent several request to site owner and no response. So hoping someone here can help out.
    Dan W1UWC
     
  2. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    Why not use the original resistor as it was factory selected to work with that meter?

    Is it "missing" or something?
     
  3. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page

    The manual shows R-7 as the meter shunt.

    Is there a notation on the meter showing the full scale? Usually, there will be something like "f.s. 50 uA" or something similar. If so, then it would be easy to calculate the meter shunt value.

    You can measure the internal resistance of the meter using a 1.5-volt battery and a couple of variable resistors and then, if you know the full scale of the meter, you can calculate the value of the shunt to get what the meter is supposed to read.

    Glen, K9STH
     
  4. W1UWC

    W1UWC Ham Member QRZ Page

    Yes it t didn't come with it the board was butchered badly
     
  5. W1UWC

    W1UWC Ham Member QRZ Page

    Yes your right it is R7
     
  6. W1QJ

    W1QJ Ham Member QRZ Page

    No problem, isolate the meter and measure the resistance of it with an ohm meter. Start on a high scale and drop down until you can get an accurate reading without pinning the meter. Most likely the meter is a 1 ma movement. That can be verified by checking the series resistors on the HV string and comparing to the FS reading. Once you know the resistance and the FS current you can calculate the FS voltage. Once you know that you can figure out your shunt value. If you don't know how to do that, report the values here and we will do it for you.
     
  7. W1UWC

    W1UWC Ham Member QRZ Page

    Thanks to all who provided information it is much appreciated a friend contacted me and provided the value I need. So thank you everyone.
    Dan W1UWC
     

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