This question is for those of you who are familiar with servicing many TD 126 Mk III tables in the past: is there a high failure rate of the DC servo motors in this particular model ??? Or are there other known common issues which will result in the motor failing to turn? I ask to get a headsup before I start to troubleshoot my tables. I have 2 of these tts, both of which power on, but whose motors fail to spin.