homepage › Forums › Thermo Scientific Series 48 CO Gas Analyzer Questions and General Discussion › Erratic Spikes on a 48i-TLE CO Analyzer
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May 31, 2018 at 5:08 pm #1504AmandaMVParticipant
We are finding that there are erratic spikes on the output of our 48i-TLE analyzer. We have also noted an unstable motor voltage on the diagnostic screen for interface voltages. It fluctuates constantly from 17.1V to 21.6V. Would this be related to the spikes we are seeing?
When measuring at the test point for 18.0V motor voltage, the voltage is rock steady at 19.1V. Motor speed is also steady at 100.00%.
What would be the next step in troubleshooting this issue?
Thank you.
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June 5, 2018 at 6:40 pm #1510dpengillyKeymaster
The fluctuating motor voltage from the Diagnostics screen is perfectly normal. If the motor speed is steady at 100% and the analog test point is steady, then there is nothing wrong with your chopper motor.
However, the spiking of the analyzer is not normal. Let’s start investigating at the source, literally. Try peaking the signal strength of the IR source by adjusting the inlet and outlet mirrors. We have posted the instructions on one of our previous posts. If that doesn’t help, try replacing the IR source. Finally, try swapping out the pre-amplifier.
UPDATE: the problem was the pre-amplifier. You can see from their original graph, and at the beginning of the graph below, the trace was noisy, had occasional spikes and the auto-zero was erratic. After replacing the pre-amplifier, everything improved.

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