This sounds like a problem I experienced with a different EA, and which had a very simple solution. In my case, the key point was that the temperature sensor in the oxidation oven is not as stable as it should be. If you're using tin capsules, the oxidation is exothermic enough to cause a flash of heat that can be sensed outside the heating column. If the tip of the thermocouple is too close to this flash, then it registers the increase in heat and the electronic logic then tries to adjust the heat to reach the set point. Until the microprocessor sorts out the right current to apply and temperatures become stable (which can take > 6 minutes), you don't get a "Ready" signal because temperatures haven't been stable for long enough.
The solution, recommended from the manufacturer, was to slide the thermocouple down 1 cm or so, to a height where the flash of heat from the tin oxidation wasn't felt so intensely. The repair took 30 seconds, and the instrument behaved normally almost instantly. You might have to loosen a screw a bit to reposition the thermocouple, and then retighten enough to make sure it doesn't slide by itself.
Good luck, and let us know what fixes your problem.
From: Stable Isotope Geochemistry [[log in to unmask]] on behalf of Turner, Ben [[log in to unmask]]
Sent: 20 May 2011 15:38
To: [log in to unmask]
Subject: [ISOGEOCHEM] Flash 1112 problem
I have a problem with a Flash 1112 that I wonder if anyone has experienced before.
The instrument will run the first sample in a sequence, but then does not begin the next sample. The status reads 'waiting for analyzer readiness'. This is because both the 'Ready' light on the front of the analyzer and the 'Temperature Ready' light on the EA Status window switch off during analysis of the first sample, even though all the temperature readings are and remain correct. Sometimes the machine goes to ready after a few minutes, sometimes not.
I expect the solution is straightforward, but I haven't been able to figure it out so far. I will welcome any suggestions!
Smithsonian Tropical Research Institute
Republic of Panama
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