Rotor removal

That did it.  Got the case open.  No score marks on the solenoid latches, switches are all okay. Everything electrical is functioning. The door hinges have a lot of corrosion on them.  I removed and cleaned them up with some abrasives and WD40.  Ever have issues with the door springs just cycled out (stretched) and needing to be replaced?  I do not think any service was performed on these in the past 4 years. Just curious. 

Thanks for ALL of your help, Don and everybody!

What springs are you referring to?

The springs to the door on top. Close it to spin the rotor.

Sorry Jeff but it has been years since I even set eyes on an M18 so I really didn't remember springs on tge door. Anyway, I never replaced them myself so I can't really comment on actually replacing them but I can't see much use or concern for replacing them as the lid is really not very heavy so no safety issue that I can see.

Don

Don, the reason I ask is this: It appears that when you hit the lid button to open it all solenoids are working, however the lid does not rise and you get the lid error, have to cycle power or use the manual releae to get it open. There was corrosion on the lid hinge, and I cleaned that up, lubricated the hinge shaft, and inspected the springs.  Physically, the lid must be under tension from the springs to rise and disengage when the button is pressed.  However, it will not lift the lid. I would assume that the springs are either installed incorrectly or they are just not holding recommended tension.  They do not appear to be installed incorrectly. Also, when you run a cycle, it does not disengage the the latches automatically, you depress the lid open, and it clicks. Checking the electronics now.

Don, the reason I ask is this: It appears that when you hit the lid button to open it all solenoids are working, however the lid does not rise and you get the lid error, have to cycle power or use the manual release to get it open. There was corrosion on the lid hinge, and I cleaned that up, lubricated the hinge shaft, and inspected the springs.  Physically, the lid must be under tension from the springs to rise and disengage when the button is pressed.  However, it will not lift the lid. I would assume that the springs are either installed incorrectly or they are just not holding recommended tension.  They do not appear to be installed incorrectly. Also, when you run a cycle, it does not disengage the the latches automatically, you depress the lid open, and it clicks. Checking the electronics now.

So you depress the 'lid-latch' button and "it" clicks. Is it the latch clicking? Can you manually lift the lid when it clicks?

I have replaced hinge springs on these for that reason.

That is eactly the issue.  It clicks (Solenoids engage), but does not clear the houseing. You either have to lift it pretty quickly or yout get the lid error.

So order new springs. As I recall they are "relatively" inexpensive. However you may have to wait from Beckman. Try Ozark. They may have 'em. Take a red or green scotchbrite pad to the hinge pins with soapy water. If the hinge pin sockets are plastic change them too.

Jeff, do what the other contributors recommended and order the springs. The M18's that I worked on never got to the point that your centrifuge has so that's why I never had to replace them. I guess that I am starting to forget too many things about what I worked on for over 30 years that it may be tome to hang it up here.