j2-21 won't start, interlock problem

What makes you believe that there is an interlock problem?

The primary interlock that creates a no-start condition is one of the two door lock solenoids.  Can you open and close the door with the power off?  Do you hear any noises indicating that the door has latched when you push  the start button?  Is the drive belt still in place between the drive and the spindle pulleys?  If it is not, then the drive will not start.  Those are the quick and dirty things to check.  Get back to me after answering these questions and we'll go from there.

Don

Thanks Don,  I got it fixed by checking inside the door latch mechanism, you were right probably the solenoid wire connection was not well contact i didn't here it clicking before and it did not move in to block the release lever to open the lid.  TheSTART button is now lid and runs but i still need to replace the on/off switch because it only turn on when holding it at 1/2 way position,  i did cleaned it with alcohol and it worked for 1 day only.  i think it getting old, i ordered it on master electronic for $76.75.  Thanks for all your help and support.

Happy to help you get the centrifuge up and running.  The J2-21 series may not be the newest and best centrifuge around but it always has been a workhorse for many customers.  It's a good thing that you didn't try to order it from Beckman becuase I'm sure that you would have paid a lot more for the breaker than $76.75.  They just raised their prices again to absolutely ridiculous levels.  Their greed creates their need and they wonder why they're losing service agreement customers.

Don