Normally Code 23 is a hard fault, and is an open in the transistor circuit. You will normally have to check Q1, and it's related circuit, which is the drive motor, the parts on the heat sink where you find Q1 (Rec1, maybe rec2, c-1 and r-1), and the power card. Normally you will find that Q1 is blown, and the power card is faulted. Q-1 comes witha new rec1 as a kit, change it as well.. Sometimes you will find a lead burnt off of the motor. Good luck

If it's an intermitent fault let us know and we can walk you through the rest of the checks.. It helps to have the complete model and serial #. Do you have the superword as well?