CDE Controller Rebuild

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by WE9N, Nov 15, 2021.

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  1. WE9N

    WE9N XML Subscriber QRZ Page

    Hello,
    My CDE Rotor Controller unit took a dive and I found that the diode (1N4002) failed. I replaced it, along with the old paper electrolytic capacitor and resistors and have an issue with meter indication. The meter will peg way past the 180 degree mark on the right hand side of the meter, causing the indication to be about 40 degrees off. Using the calibration pot does nothing because the value is so narrow. The pot is working, but I’m thinking in order to get the meter indication to back to normal I need a larger value pot. Does anyone have any recommendations or input on what I could be missing?

    Thank you-WE9N
     

    Attached Files:

  2. W9IQ

    W9IQ Ham Member QRZ Page

    You didn't mention the model number of the rotor but it sounds like the zener diode that regulates the meter circuit is bad. Have you measured the meter circuit voltage?

    - Glenn W9IQ
     
  3. WE9N

    WE9N XML Subscriber QRZ Page

    Hello Glenn, the model is Ham II, and I now have 13 volts DC to the metering circuit after replacing the zener diode (1N4002) and the other components. Replacing the components have caused this issue now.

    I should clarify that the controller is working, and the meter does move but the indication is off 40+ degrees. Before the repair, I had no meter indication but it was moving the rotor.
     
  4. W9IQ

    W9IQ Ham Member QRZ Page

    The 1N4002 is not the zener. The zener diode is the one next to the transformer in the picture.

    - Glenn W9IQ
     
  5. WE9N

    WE9N XML Subscriber QRZ Page

    Ok thank you, it tested good on the multi-meter when I purchased the new components. Looks like I will order a new one and see if that helps. Do you happen to know the value?
     
  6. W9IQ

    W9IQ Ham Member QRZ Page

    It is a 12.7 volt zener. Did you already replace the zener and you just misspoke regarding the part number? 13 VDC is about the nominal voltage for the supply when it is properly regulating.

    Also check that the fixed resistor that is series with the meter is 10k ohms.

    - Glenn W9IQ
     
    Last edited: Nov 15, 2021
  7. WE9N

    WE9N XML Subscriber QRZ Page

    I replaced D-2 according to this schematic. D1 is the Zener.

    I am getting 12.7 - 12.5 volts to the metering circuit now...I think I may need to reevaluate the resistors going from the fuse to the meter. Old resistors were 10k ohms and I replaced them as such. However, this schematic shows only one 10k resistor.
     

    Attached Files:

  8. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    There is supposed to be a 10K resistor between the fuse and the + terminal of the meter.

    Per your photo, somebody changed that and it looks to me like there's now a pair of 1/4W resistors in parallel there, and the value of each resistor seems to read 10 Ohms.

    That will never let you calibrate the meter. I'd remove what's there and install a 10K Ohm resistor like it's supposed to be.

    Oops I cross-posted this with your last post. Maybe the image is confusing for those resistors. But if they're really 10K each (doesn't look like it, but maybe), two in parallel is still wrong. Use just ONE 10K Ohm resistor. Make sure it's really 10K not 10 Ohms.
     
  9. WE9N

    WE9N XML Subscriber QRZ Page

    Thank you everyone for your help. I removed one resistor and it still was giving me issues. I always wanted to convert the controller to computer control and bought the EZ-Rotor kit. I’ll update the thread with my results from the kit late next week (I’m planning on installing it over the thanksgiving holiday).
     
  10. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Removing one resistor won't help anything if it's the wrong value resistor remaining.

    Did you try a real 10K resistor, like it should be?
     

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