Patrick1 Report post Posted December 31, 2022 I upgraded my friends CB-3500 with a needle positioner like my Cobra 4. When I added it to my Cobra 4 I purchased the whole kit, motor, box and needle positioner. I had a hunch I would have compatibility problems with the electronics box that my machine came with and sure enough I kept getting errors so all I did was replace the box and it worked great. I also added the Extreme narrow feed dog and stainless flat plate with a Cobra style presser foot. He wanted to see the needle better than you can with the Cowboy supplied foot. Quote Share this post Link to post Share on other sites