Subsystem Checkout; Ac Mains Configuration - Teledyne 300E Instruction Manual

TROUBLESHOOTING & REPAIR PROCEDURES
2. Detector failure – caused by failure of the hermetic seal or over-temperature
due to poor heat sinking of the detector can to the optical bench. In addition
to increased noise due to poor signal-to-noise ratio, another indicator of
detector failure is a drop in the signal levels of the CO Measure signal and CO
Reference signal.
3. Sync/Demod Board failure. There are many delicate, high impedance parts on
this board. Check the CO MEAS and CO REF Test Functions via the Front
Panel Display.
4. The detector cooler control circuit can fail for reasons similar to the detector
itself failing. Symptoms would be a change in MR RATIO Test Function when
zero air is being sampled.
Also check the SIGNAL I/O parameter PHT DRIVE. After warm-up, and at
o
25 C ambient, if PHT DRIVE < 2500 mV, the cooler is working properly. If
PHT DRIVE is > 2500 mV there is a malfunction.
5. The +5 and ±15 VDC voltages in the M300E are provided by switching power
supplies. Switch mode supplies create DC outputs by switching the input AC
waveform at high frequencies. As the components in the switcher age and
degrade, the main problem observed is increased noise on the DC outputs. If
a noisy switcher power supply is suspected, attach an oscilloscope to the DC
output test points located on the top right hand edge of the Relay board. Look
for short period spikes > 100 mV p-p on the DC output.

11.5. Subsystem Checkout

The preceding sections of this manual discussed a variety of methods for identifying
possible sources of failures or performance problems within the analyzer. In most
cases this included a list of possible causes. This section describes how to
determine individually determine if a certain component or subsystem is actually
the cause of the problem being investigated.

11.5.1. AC Mains Configuration

The analyzer is correctly configured for the AC mains voltage in use if:
The Sample Pump is running.
§
The GFC wheel motor is spinning (a slight vibration should be apparent to the
§
touch).
If incorrect power is suspected, check that the correct voltage and frequency is
present at the line input on the rear panel.
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Model 300E Carbon Monoxide Analyzer
Instruction Manual
P/N 04288 Rev: A