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  1. #1
    300+ Forum Addict jmig's Avatar
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    A lot of noise in Pots

    I replaced the bad potentiometer on my control stick. Now when I try and assign the axes in FSUIPC I have a lot of jitter or noise. The noise is so great that I can get the correct axis to register in FSUIPC when I rescan.

    I am using Bourns 53 series pots which are supposed to be more accurate than standard pots. I am running through an Opencockpits USB Axis card and using shielded wire.

    Any ideas?

    John

    System:
    ASUS P5Q SE/R
    Intel Q9550 O/C to 3.4 GHz
    4 GB 1066 DDR2 RAM
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  2. #2
    300+ Forum Addict phil744's Avatar
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    How long is the wire betwen the POT and the USB card? if it over 2 meters try moving the USB card closer to the pot. That worked for me on another non sim project using pots.

    And obviously adhere to the basic rules like not running low voltage cables with high voltage cables.

    I dont know what the Opencockpits USB cards look like but if they have any electrolytic capacitors on there check for any leakage on the base of the cap or expantion on the top, they really can screw things up. also, if you are using an external PSU to supply the card, swap it for another to see if that helps.

  3. #3
    300+ Forum Addict jmig's Avatar
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    Thanks for the suggestions Phil. I think the problem is from the Axis card. I tried swapping the pitch and yaw connections and regardless of where they are OR, which one o both are connected I get the noise.

    If I disconnect both the noise stops. I will try and connect a couple of new pots by themselves and see what happens. One will be the Bourns the other will be a standard Radio shack pot.

    I wonder if it could be a grounding issue? The is no way to ground the IO card directly to a ground
    John

    System:
    ASUS P5Q SE/R
    Intel Q9550 O/C to 3.4 GHz
    4 GB 1066 DDR2 RAM
    300 GB WD 10,000 RPM Raptor SATA Drive
    GeForce 8800 GT 512 KB RAM
    Matrox TH2Go with three 19" Sumsung 940 BX
    IR Track 4

  4. #4
    300+ Forum Addict Rodney's Avatar
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    You can't piggy back of one of the ground pins? How about the mounting holes? Solder a wire there and ohm it out. I haven't ever seen a pcb that didn't have a ground pin/hole/pad on it. For noise, the shortest wire you can reduces it.
    Rodney -
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  5. #5
    2000+ Poster - Never Leaves the Sim Michael Carter's Avatar
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    Try grounding the case of the pot. If that doesn't work, try floating the ground on the computer or power supply unit to the card.

    It's not generally recommended for safety reasons that I'm sure you're aware of, but if it's otherwise reasonably safe, try it.

    Several components in my recording studio have had to have the grounds floated to eliminate 60Hz hum. Same thing can happen with anything.
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  6. #6
    300+ Forum Addict jmig's Avatar
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    Well, I think I have just blown the card. I connected a separate pot to it to try and see if it was the pots. There are three pins for each pot. 5v, data, GND. I used a three pin connector. I plugged it on backwards. GND and 5 v reversed.

    I got a dialog on the computer screen saying the USB hub had received an over voltage and had shut itself down to protect itself.

    That is when I noticed the plug was backwards. These are naked pins with no alignment male end. I also noticed the red LED was out. I tried moving the USB cable to another series of USB ports then removed the board and tried it on another computer. No joy. It is not recognized by the computer and when I open the game controller applet, the Opencockpit IO card doesn't show.
    John

    System:
    ASUS P5Q SE/R
    Intel Q9550 O/C to 3.4 GHz
    4 GB 1066 DDR2 RAM
    300 GB WD 10,000 RPM Raptor SATA Drive
    GeForce 8800 GT 512 KB RAM
    Matrox TH2Go with three 19" Sumsung 940 BX
    IR Track 4

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