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avatar: Negotiator
Negotiator
5 posts
Replied to Negotiator's post on February 27th, 2018

First, I want to say that there is a strange sort of creaking/grinding noise when the lid is being released from the lid latch mechanism. I have yet to diagnose this (it may be the motor being too weak to grab hold of the ring or the lid latches are too worn down to grab perfectly). Second and final, if you hold down with some force, the lid will stay down and the centrifuge can be used as normal.

Now that background is established, here is the question: is there a way to adjust the gas spring for this system? I just replaced the gas spring as the lid was not being held open on its own. Looking at the old spring, I do not see a place where one could use an allen key to release pressure from the spring.

Prior to replacement, the lid never had issues of popping back open as it does now. It appears the spring is too stiff relative to the lid latch mechanism to remain closed without some force.

Any ideas?

avatar: WarwickJon
WarwickJon
43 posts
Replied to Negotiator's post on February 28th, 2018

Hi, 

Do not try to adjust the gas strut at all.  This is a sealed unit and it would be dangerous to try and adjust it.

You may need to check the mechanical operation of the lid latch mechanism.  It may need a little lubrication or adjustment.  It's not hard to get at via the removal of the front panel.

Cheers

Jon

avatar: Negotiator
Negotiator
5 posts
Replied to WarwickJon's post on February 28th, 2018

That is sort of what I assumed, but I thought I would ask before playing around with it. Since it is already installed, it is also not worth my time to extract it now anyway.

 

Concerning the removal of the front panel - how do you actually get the top portion (near the buttons and control panel) removed? I took off the two screws at either side and there appears to be an allen key insert between them. I was not going to play with that before confirming its function. Is that the ticket to getting it off? 

Otherwise, it appears to not come off easily at the top.

avatar: Negotiator
Negotiator
5 posts
Replied to Negotiator's post on February 28th, 2018

I think I know how to take off the front panel, but now something else has come up: I am balancing my tubes to the nearest 10 mg or so (I am centrifuging about 45 g worth of material in a 50 mL falcon tube, so this seemed sufficient), but I am now getting imbalance issues sometimes.

I think this has been abused a bit in the past, but I was curious if I might need to take off the rotor perhaps? It is even shaking a bit suggesting that there is an imbalance, but the scales do not agree.

Any ideas?

avatar: WarwickJon
WarwickJon
43 posts
Replied to Negotiator's post on March 1st, 2018

Sounds odd.  Does it run in balance with the rotor in with no samples? If not, i would suggest the rotor is scrap perhaps given your description of it being abused.

Is it a fixed rotor or one with buckets?

Cheers

Jon

avatar: Negotiator
Negotiator
5 posts
Replied to WarwickJon's post on March 2nd, 2018

Yes, it seems to be fine. I went through a couple of trials with other masses and it appears to be...fine. Might have just been a fluke.

One final question as this has never happened to me in previous labs: there is a distinct grinding noise when the latch mechnism disengages when opening the door. I took off the front panel and it appears that the central component that moves vertically to control these latches might be grinding up against the outer housing. Has anyone experienced this? 

I thought it might just be the latches, so I used a mild lubricant and tried again, still grinding. I tried to simply lubricate the central control arm, but still heard the grinding. I noticed some discoloring on the housing. If this is it, any ideas on an actual fix?

I could try filing down the metal that is making contact, but this has never been something I have experienced, but both 5810R centrifuges here make the same (to different degrees) sound upon the latch disengaging to open the lid. Very, very weird things going on with these centrifuges...

Thanks for the help so far, Jon.

avatar: SaharaSimba
SaharaSimba
49 posts
Replied to Negotiator's post on March 5th, 2018

You cannot adjust the Lid Pressure damper, you should just replace it.  Think it is about $80-100 from Eppendorf for the part.  It can be accessed by removing the back panel.  It is just clipped in most instances.  

avatar: Negotiator
Negotiator
5 posts
Replied to SaharaSimba's post on March 13th, 2018

Thanks for all the help. The balancing seems to be functioning perfectly now and no other functional issues have arisen.

However, I just have one matter that I still have yet to solve and it is that both of these centrifuges exhibit a weird grinding sound (metal on metal) only you press the 'open' button and on the initial steps of opening the lid - this does not occur when closing the lid.

What I saw and assumed to be the source of the problem is that the central mechanism that controls the arms appears to grind up against the housing of the centrifuge itself.

Any ideas?

avatar: WarwickJon
WarwickJon
43 posts
Replied to Negotiator's post on March 14th, 2018

Quote Negotiator

Thanks for all the help. The balancing seems to be functioning perfectly now and no other functional issues have arisen.

However, I just have one matter that I still have yet to solve and it is that both of these centrifuges exhibit a weird grinding sound (metal on metal) only you press the 'open' button and on the initial steps of opening the lid - this does not occur when closing the lid.

What I saw and assumed to be the source of the problem is that the central mechanism that controls the arms appears to grind up against the housing of the centrifuge itself.

Any ideas?

Hi,

Cant say I've come across this issue before.  There should be enough clearance between the latching mechanism and the front panel.  Is the main latching shaft bent at all?  I cant imagine how this would bend though.

The latching mechanism hasn't become detached at all has it from its main contact points?

You could try lubing the actual hook and loop part of the latching mechanism lighlty with something like copperslip.  

Without seeing it, its difficult to diagnose.

Cheers, Jon