Just to clarify, I have the Logitech Flight Yoke System, which includes the yoke and a throttle quadrant (connected directly to the yoke via PS/2). Everything worked perfectly.

Now, as I'm training for my Multi-Engine rating, I thought about adding a second throttle quadrant to improve the experience. So I bought a used one. But the moment I connected it and slightly moved one of the throttles, everything went crazy. Buttons and controls in the virtual cockpit started activating randomly.

I downloaded the Logitech mapping software, and when I connected the used quadrant, I saw all kinds of input combinations switching rapidly on their own—it was complete chaos. But when I plugged in the original one, everything was fine.

My first thought was that the used one was broken, so I got a refund. Yesterday, I received another used one—and it’s doing exactly the same thing.

Now I’m starting to wonder if the issue is something on my end. But I don’t know… these devices are supposed to be plug and play. I’ve never needed to install any special drivers before. I also purchased a PS/2 to USB and connected the throttle directly to my computer USB, and it's doing the same...

What do you guys think might be happening?

The Logitech looks identical to the Saitek I’ve previously owned.

If you have a spare USB port on the right of the Yoke hub that’s where the second quadrant should be plugged in. Is that where you’ve plugged it in?
 

Don’t worry about the Logitech software. You don’t need it. Go into Control Panel - Game Controllers and see if Windows is correctly recognising each component including the second quadrant.

If it’s second hand it’s possible the potentiometers are worn. If they are the quadrant is useless and you should request a refund as the seller isn’t being honest.

If the software shows spiking when you move the levers that’s definitely worn pots.

https://www.makeuseof.com/test-calibrate-gaming-controller-windows/

53 minutes ago, Ray Proudfoot said:

The Logitech looks identical to the Saitek I’ve previously owned.

If you have a spare USB port on the right of the Yoke hub that’s where the second quadrant should be plugged in. Is that where you’ve plugged it in?
 

Don’t worry about the Logitech software. You don’t need it. Go into Control Panel - Game Controllers and see if Windows is correctly recognising each component including the second quadrant.

If it’s second hand it’s possible the potentiometers are worn. If they are the quadrant is useless and you should request a refund as the seller isn’t being honest.

If the software shows spiking when you move the levers that’s definitely worn pots.

https://www.makeuseof.com/test-calibrate-gaming-controller-windows/

Yes! I have the Saitek, here is the one I have

https://images.mypilotstore.com/hr/5471-highres.jpg

Nice to know I should plug the second throttle quadrant to the yoke, but in any case, both of the times I connected the new Throttle Quadrant directly to the PS/2 on the yoke and it did the same thing... I'm guessing I'm just having bad luck? I was wondering if there could be some weird registry things messing up, but again, these things are Plug and Play... I'll definily try that test to calibrate and see how it goes. I still have a couple days to play with the new one. 

Unplug the Saitek and plug in your second throttle quadrant only. Test it in isolation. That way the yoke cannot interfere unlikely though it is.

If the problem persists it’s definitely faulty.