New member, longtime forum browser. I have a 1999-2000ish okuma mv4020 w/ u10m controller that I acquired a few months ago, and recently have started having issues with the tool change stalling out on sequence 4. Under diagnostics it will show the "15711 switching to TS axis is not complete". I can power off the controller and back on, then I hear a click of what i assume is the pin locking the magazine wheel back. Then it will change tools again, and might run a program a few times before stalling out again with the same error. It is always cleared with restarting the controller, but will happen randomly. It seems to be where the tool changer is supposed to swing the pot down vertically where it stops. Thanks for any advice. I'm about to take delivery on another older okuma machine need to figure out how to work on these, the manuals seem of have 1000's of pages, but no troubleshooting.