I am working on a ACNR 30 S stand up machine with NYK controls. The controls that are in it are SU50-26 SCR control, with a pb30-10ul card, 3 different colored circuit blocks that are mpb30-55, mpb30-23, mpb30-52, PB80-40f, pb80-30f circuit boards in the speed control, Symptoms are that it will not always run on the speed control. If the high speed contactor is pushed in the motor works either way. Sometimes it starts working again by it's self. I am looking for help and a source for parts so that I can make a more educated guess as to which board would cause this. This lift has worked for me after I have cleaned the cards, connectors, and put everything back. It will then fail later on and sometimes when I arrive, it works fine for me. Thanks in advance for your help.