Knight:5810R centrifuge

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This centrifuge can spin 225mL tubes, 50mL conical tubes and 14mL culture tubes in the swinging bucket rotor. The fixed angle rotor can accept 50mL conical tubes and possible 14mL culture tubes with the right adaptor.


Maximum centrifugal force

50mL polypropylene tubes can take 9400 RCF.

15mL polypropylene tubes can take 8400 RCF.

Known issues

Recognizing the wrong rotor

On 5/18/2005, the centrifuge kept indicating an imbalance with the fixed angle rotor even in the absence of samples. The swinging bucket rotor seemed to work fine. Cleaning the rotor, power cycling the centrifuge, swapping rotors in and out, unplugging the centrifuge all failed to solve the problem. Later in the day, Tom played with the temperature, speed and timer settings and the centrifuge started working again. The centrifuge appeared to be recognizing the rotor incorrectly. The max RPM setting was correct but the max RCF setting was wrong indicating that the centrifuge thought a rotor of different diameter was in there. Eppendorf technical support was baffled by this result but think there might be a problem with the EPROM.

Below is a copy of the correspondence with them. It is included not because it is particularly interesting but to save others the trouble of corresponding with Eppendorf about the problem.


We have an Eppendorf 5810R centrifuge. Whenever we place our 36-6-38 fixed angle rotor in it (empty of all tubes and without a lid) and start the centrifuge, within a few seconds, it says that there is an imbalance and stops.

We tried the following

1) power cycling the centrifuge 2) unplugging and replugging in the centrifuge 3) cleaning the rotor and the centrifuge itself (and reapplying vaseline spray) 4) reseating the rotor to make sure it is sitting properly

The centrifuge does recognize the rotor when you put it in, spin the rotor counter-clockwise and hold the start button. The centrifuge recognizes and runs when we put in our swinging bucket rotor.

Do you know what the problem might be? Do we just need a new rotor? Is this a common problem?

Thank you for your time.

It is possible that your centrifuge is having a problem with the EPROM and the rotor you want to use is blocked out for some reason. It is also possible that the rotor itself is at fault and can't be run. I can't say for sure which is the actual issue here. I can say that the imbalance values in the controller are functioning ok since you are able to run other rotors. If the imbalance values are bad or the sensor itself was bad then you would not be able to run any rotors. I recommend service for this unit just in case it does turn out to be a controller issue with the EPROM. The rotor you're trying to run is a common rotor so there should be no problem there. I've listed contact information to schedule service.
To schedule service or check warranty status please call our Repair Administration dept. at 1-800-645-3050 ext.2404. Please let them know that you have been in contact with myself through this email.
One of the people at Brinkmann mentioned something about recalibrating the rotor. She said "you have to go into the service part of the program on the centrifuge and while spinning certain weights they enter values into the program." Is this the same thing as having a problem with the EPROM. Is it something that we have to call a service rep in to do or can we do it ourselves?
Actually, you can't calibrate a rotor, you can only calibrate the imbalance to the unit itself. The imbalance value can be ok while the EPROM can have a problem or just can't run that rotor for some reason. It is this reason why I recommended service. You don't really want to try doing a few things just in case it makes things worse. As of right now you can at least run other rotors. I definitely recommend having a field service tech come in to check the unit out. I've relisted The # to call for service.
To schedule service or check warranty status please call our Repair Administration dept. at 1-800-645-3050 ext.2404. Please let them know that you have been in contact with myself through this email.
I have one final question. Suddenly the centrifuge started working again. Another person in the lab played with the temp, speed and timer settings and it started working again. Based on his playing around, he thinks the centrifuge wasn't recognizing the rotor properly. The centrifuge got the max RPM for the rotor right (which is why we originally thought the rotor was being recognized correctly) but he thinks it got the rotor diameter incorrect because it did not have the correct max RCF setting as he played around with it. Now it appears to recognize the rotor properly with the correct max RPM and RCF settings.
Does this information give you any more insight into what the problem might be? Have you seen this before?
Wow, sometimes these things just can't be explained. Playing around with the settings should not have made a difference because the rotor information is stored in the EPROM. When you put a rotor on to run the EPROM will let the controller know how fast it should go and all that. In this case it looks like something just came around or just woke up. I don't know how to explain this. I've never come across this either. Sometimes electronics can play weird games. I'd say to just keep running the unit as long as you can. Hopefully the situation will not come back but if it does then place a service call. I still think the issue was an EPROM problem but somehow it cleared itself. Let me know if things change.