Replied to rogerwagner79_5227's post on June 26th, 2017


I recently replaced a couple of blown capacitors on the interface board and now the unit fails to maintain a low vacuum.

The rotor will achieve around 40,000rpm and then display drive error. Using S604 on the interface board it displays the vacuum going down to zero then the vacuum pump will switch off and it will rise up again and cause issues.

Is there a way to adjust the vacuum guage? Is there a service manual available?

avatar: bberg7794
15 posts
Replied to rogerwagner79_5227's post on July 7th, 2017

Are you sure you aren't actually experiencing a "drive" problem, like a broken shock mount or bad speed sensor?

If I remember correctly from our machine, once a "drive" error is triggered, it shuts down the vacuum.  From your description, your machine may be operating correctly.

See posts from February 1st, 2016 and September 29th, 2016 on this forum regarding my issues with a "drive" error.


avatar: dpkleessr
1122 posts
Replied to rogerwagner79_5227's post on July 7th, 2017

There is a profound difference between "DRIVE" errors and a "VACUUM" problem and NO, the vacuum is NOT released when a drive diagnostic occurs and there is a rotor spinning in the chamber. That action is specifically prohibited in EVERY ultracentrifuge that Beckman ever manufactured. Vacuum issues on the TL100 series of centrifuges were fairly common ranging from problems with the metal vacuum tubing going into the side of the chamber, vacuum hose issues, and especially problems with the connector pins on the vacuum sensor cable. I would first just try turning on the centrifuge with the door closed and slowly back off the connector from the sensor while wiggling it slowly. If you see a sudden drop in the vacuum then you have found your problem. You can take the connector off the sensor and CAREFULLY insert a small screwdriver to move the pins inside of the connector slightly together. Do not push them so far that they touch each other but tightening them up fixed many vacuum issues during my 33 years with Beckman.


Replied to rogerwagner79_5227's post on July 7th, 2017
Thanks for the replies. I may not have described the behaviour thoroughly. The unit is coming up with drive and vac errors. After reading the previous posts, checking the led's, the drive is unable to control the speed, which I suspect is due to a lack of vacuum. When I monitor the vacuum it fluctuates from zero to around 500 with the vacuum pump switching on and off. I suspect that a value of zero should be impossible, and I am not sure if the vacuum pump should switch on and off during operation.
avatar: johnpudel
1 posts
Replied to dpkleessr's post on November 28th, 2018

Hi Don, I am working with a VAC problem also. Turn it on and after about 1 min the VAC light goes out. The problem is after 35-40 mins the VAC pops back on. went through all your advice as in bellows mounts o-rings diffuser oil rebuilt pump and new hoses and filter on the pump. The centrifuge operates normally for that first 35-40 mins until the VAC pops back on. I'm lost, sorry if I'm adding to this thread but I'm new to this group. thanks