Discussion Category:  Centrifuge

"Lid" Error Message

Hey all,

I just got my machine running a few minutes ago after a minor circuit breaker repair. For some reason I keep getting the LID error after running the machine at 3200RPM for a couple minutes. The lid is well secured as far as I can tell. 

Any ideas what the reason might be for this message?

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Asked by

mrwright
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avatar placemarkReply by
medphysteo

The lid may be mechanically latched but you might have an issue with the switch(es?) in the latch assembly, or possibly a loose connection to the circuit board (since you had it fully dismantled, it might be good to double-check). At the top of this page you'll see "View Thermo Scientific IEC Centra GP8 product details" under your post's title. Click on that link, then on the Documents tab where you'll find a service manual. 

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avatar placemarkReply by
mrwright

When you say the switche(es), are you referring to a component in the latch or on the circuit board? I see no loose connections on the circuit board. 

Thanks again

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avatar placemarkReply by
medphysteo

Inside the latch assemblies. Each latch unit has two switches (according to my paper manual; according to the manual on the site, one each). All switches have to be fully and securely closed for a run. You may have a mechanical or connection issue inside a latch unit, or maybe your lid isn't quite square/level after reassembling. If it was working before I'd check the lid first.

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avatar placemarkReply by
mrwright

I'm faily certain that I found the issue. Does anyone know where I can find the wire connector that attaches to J1 on the circuit board? What are those things called?

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avatar placemarkReply by
medphysteo

It's an older version of an AMP Universal Mate-N-Lok single row 5-position wire-to-wire connector. Current versions are 926299, 770016, and 770019, all of which may be followed by a -1 or -3. 

http://www.te.com/usa-en/plp/rectangular-connector-housings/Y30mo.html?q=&d=58312%20125101%2043350%2028886%2022651%2083253%2060331%2091339&type=products

You've probably got an electronics supply place locally that can supply or source them for you. Or you can get them on line from Allied, Mouser, or Digi-Key.

 

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avatar placemarkReply by
mrwright

Thanks for your responses thus far. The notes have been extremely useful.

The service manual suggests testing the resistance between pins 2 and 6 on each of the interlock switches to determine if they're working properly. I can't get a reading at all, with the lid up or down which is concerning. I have a feeling that these interlock switches might need to be replaced. A quick google search turned up a few sources for replacement interlock assemblies but they are seriously expensive. Is it possible to replace only the switches as opposed to the entire assembly?

I can't seem to find a replacement part # for the switches. medphysteo, you seem to have more experience than most with this machine. Any suggestions?

This machine is headed for the dumpster if I can't come up with less expensive fix. 

 

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avatar placemarkReply by
medphysteo

It's been over 10 years since I had a latch issue with my machines so I can't remember every step of the process I had to take then, but ultimately I did have to replace a latch assembly. The switches in the latch are made by Marquardt, and I ordered some p/n 1117.0201's but I don't remember if that was an original or a sub. I'm also looking at p/n 1116.0105, which doesn't come up on their website. You could contact them if you have something different.

It's strange you can't get a meter reading when it will work up to a certain speed. Are all the connector pins tight at the latch connectors and the circuit board? I've seen the socket pins spread open and need to be squeezed back together. You can also clean them with a needle file to ensure a good contact.

Do you have the latches open? Are the mechanisms moving properly? Are the switches clicking over when actuated? The switches themselves can be taken apart by carefully separating the shell with a small flat blade screwdriver, and the contacts acan be burnished. Take it slow and mind the spring on the 1117's - they're a bit tricky going back together but a 6" steel machinist's ruler helps to hold everything in place while you set the other half back in place.

When you close the lid are both interlocks engaged equally and simultaneously? Are the lid eyebolts adjusted equally?

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avatar placemarkReply by
medphysteo

And before you throw it out, try ThermoFisher tech support or Ozark Biomedical. They'll both have more experience than me.

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avatar placemarkReply by
mrwright

The connector pins appear tight at the latch connectors as well as the circuit board. Latch mechanisms are working well. The switch attached to the solenoid makes a noticible "click" when pressed. The switch attached to the connectors - do not make a noticble "click" at all. The interlocks are engaged equally when the lid id closed and the eyebolts are currently at equal length. 

I just got off the phone with the folks at Ozark. Nice people. They did some quick troubleshooting with me and determined that the issue is most likely stemming from the interlock switches. A have a pair on their way. We'll see how this plays out. 

Thanks again!

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avatar placemarkReply by
medphysteo

You're welcome. Let me know how it goes.

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