Last summer I bought a fairly nice straight key. I was using it with a code practice oscillator and didn't notice this problem until I used it with a KX3. It had high key-down resistance, around 10 ohms or higher, and the resistance decreased if I pushed on the key's knob a little harder than usual. This caused a horrible "chirp" in the sidetone. After disassembly, I found the ball bearings were sliding in the trunnion blocks, and there was a setscrew for each bearing. The bearings stopped sliding after I tightened the setscrews. This got the resistance down to 2 ohms or so, but the KX3 still had a slight sidetone "chirp" when I used this key. There was no chirp at all with the Bunnell Triumph. Something was still wrong. I measured 0.5 ohms across the ball bearings and 1.0 ohms from the moving contact (at the end of an adjustment screw on the lever) to the lever itself. I drilled and tapped holes in the lever and base for two 6-32 button head screws and installed a "Kent strap" to jumper around the bearings. This lowered lever to base resistance to almost zero. It is completely invisible from the front and barely visible from the back, if you look between the trunnion blocks. I also ran a 8-32 tap through the hole for the moving contact to remove any possible paint contamination, and this lowered the resistance from contact to lever to almost zero, too. Final key-down resistance measurement after adding the strap and chasing the threads = 0.1 ohms, and the KX3 no longer chirps. I thought I would share this, not as a condemnation of the key, but as an example of how some basic troubleshooting can sometimes solve a problem. Of course, you may have to disassemble the thing. I still send my watches and cameras to a professional repair shop, but this straight key was just a fancy on/off switch.