Discussion Category: Centrifuge
Door will not release all the time and start button will not activate machine. Pressing down hard on the lid usually solves the problem. I suspect the micro switches are faulty. Where might I obtain these switches?
I just had a sticky right side solenoid and was able to correct the issue. There are five screws (metric 3 mm allen) for the lower front panel. Two on the left, two on the right, one on the bottom middle. I removed those five screws.
The top panel has two tabs (left/right) coming down from the front side of the panel and held in place by one philips head screw on each side. I removed both philips head screws.
I was able to lift the top panel enough to remove the black gasket from around the rotor chamber. This allows the top panel to be shifted up enough to access the screws for the door latch assemblies.
There are two screws for each latch assembly (3 mm allen). Remove the two screws being careful to not let the screw or washer fall into the electronics. Once the latch assembly is free, you can lift the top cover up enough so that the latch assemblies can also be lifted and clear the mounting panel.
I used an alcohol prep pad to clean the solenoid plunger. This was enough to prevent the solenoid plunger from sticking. I also applied a tiny bit of lithium grease.
Replaced more latches for bad switches than I can remember. When you work for a big company, they got on our case for replacing switches when just slamming a new latch into it would be the quick fix. It got to the point where they wouldn't allow us to even order switches so unless we purchased them ourselves we just did what we were told. And then there was justifying the purchase of service parts on our expenses. Not worth the hassle. Time IS money to a big company. Also, I would be very careful about filing anything but if it is your instrument then do whatever you want. I also found an old door latch while looking for my old service manuals and it did not have any grease on it so if they are greasing them now there must have been a reason why but I would definitely remove it and throughly clean the grease from the inside of the solenoid and the plunger. Beckman used many solenoids over the years but we never lubricated them. We did clean them up but that is all. One other thing, it may say Beckman Coulter on it but the Microfuge 18 and 22R are NOT made by Beckman. They come from Sigma in Germany.
22r latch question response
The latch mechanism gets sticky and should be disassembled and cleaned if there is any grease. Also I found that rounding out f the sharp points on the top cam with some judicious filing ,where it contacts the lower cam helps alot. I've never seen a microswitch go bad.
Thank you for your prompt reply. I'm sorry for the confusion. It is actually a thermistor from the board of Microfuge 18. The numbers on the thermistor are SL12 15004. I was trying to attach the picture of it but this window would not let me. If you provide me with your email I'll email you the picture.
OK, you posted a Microfuge 18 question on the Microfuge 22 section so which centrifuge are we talking about? If it is a Microfuge 18 then I would be surprised because the last Microfuge 18 I worked on was not refrigerated so it would not have a thermistor. If it is a 22R then I am really surprised because it is a static component in a very low voltage circuit. Get back to me.
Ive just replaced a burned out thermistor on my Beckman 18 but soon after it burned out agian. Any idea what might be causing it?
It sounds as if you have a door latch issue which if yoy read all of the posts about the Microfuge 18 and Microfuge 22R will give you some direction as to how to proceed.
I have a Beckman Microfuge 18. The "Door Open" indicator in on even when the door is shut and the rotor will not spin. What do you think the problem is?
Thank you in advance.