[Automated-sequencing] Re: DNA SEQ: 3730 Tray on Deck errors

Phillip SanMiguel pmiguel at purdue.edu
Tue Sep 5 20:41:57 EST 2006


> Date: Tue, 5 Sep 2006 14:30:26 -0400
> From: Robert Lyons <boblyons at umich.edu>
> To: ABRF Discussion List <ABRF at list.abrf.org>
> Subject: Re: DNA SEQ: 3730 Tray on Deck errors
> 
> On Sep 5, 2006, at 12:24 PM, Phillip San Miguel wrote:
> 
>> The FSE will almost universally warn us that sensors can be damaged  
>> by liquids being spilled on them. But then just as universally note  
>> that there was no evidence that this had occurred with our sensors.  
>> (The sensors are dry and have no buffer residue on them.)
>> <...>
>>     Has anyone else been seeing sensor issues in their 3730's?
> 
> 
> Hi, Phillip -
> 
> We, too, have often encountered bad sensors. For a while there it was  
> so frequent that we kept a stock of them in-hand and installed them  
> ourselves when directed by the FSE. (Of course, that may have been  
> over-kill, and I suspect some sensors were replaced when they didn't  
> in fact need replacing. It also may be against company policy, but  
> that FSE has left the company for greener pastures and can't get in  
> trouble for this now. :-)
> 
> We don't run 384-well plates, but otherwise the description sounds  
> like what we kept seeing. Especially your talk about fluid spills -  
> we were often warned about spilling fluid on the sensors, yet often  
> the blown sensors whould show no evidence of fluid spill.
> 
> Here's a long-shot: the last time we had some sensors replaced, our  
> FSE noticed that the ground wire on the gripper was broken. It's  
> possible that this exposed the sensors to some voltage spikes that  
> ordinarily would have been dissipated by the ground wire. Certain  
> electronic components are exquisitely sensitive to static  
> electricity, which is omnipresent unless properly grounded. The  
> ground wire is a small (~18 Ga) white wire on the left side of the  
> gripper, visible when you remove the buffer tray. In our case, that  
> wire appeared to be connected, but had in fact flexed and was not  
> electrically connected.
> 
> Good luck, sir!
> 
> - Bob

Thanks Bob,

	Interesting you should mention that your FSE gave you sensors to 
install yourself, should the need arise. Just recently that happened to 
us as well. Our DNA sequencing manager swapped the gripper sensors 
(plate type sensors) this weekend after we got a plate-type mismatch 
error. Alas, this just resulted in a new type of error. Now upon reboot, 
the machine generates an error indicating that no communication with the 
AutoSampler is occurring (something about "Autosampler serial port 
communication failed"). Same with the pump.
	Anyway, will definitely have the grounding wire checked.
	
-- 
Phillip



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