Teledyne API Model 200AH NOX Analyzer Instruction Manual, 06492, Rev. G2
9-49
PSM Diagnostic procedures:
The Linear Power Supply board can be tested by checking the DCPS - TEST function on the
front panel. It should read 2500 mV 200 mV. If the value is outside this range, individual
output voltages can be tested on connector P3, see the schematic in the Appendix for pinouts.
The Switching Power Supply output can be tested by observing the red LED on the TEC control
board attached to the inside of the fan duct on the Sensor Module. If the LED is on, +15 VDC is
being supplied to the cooler. The current draw through the cooler can be measured across TP1
and TP2. The value of the current in amps is 10x the voltage measured, and is typically 1.5 to 2.0
amps at room temperature.
The Switch Board can be tested by observing the diagnostic LEDS along the top edge of the
board. The following Table 9-10 describes the typical operation of each LED.
Table 9-10: Power Supply Module LED Operation
No. Function Description
1. NO/NOx Valve Should switch about every 6 sec. On = NOx mode Off = NO mode.
2. AutoZero Valve Should switch every 2 minutes. On = Azero Off = Sample mode.
3. Ozone Generator
Power Power to ozone generator is off for 30 minutes after turning on an
instrument that has been off for a long time.
If the instrument has been turned off for less than 60 minutes, the
ozone generator is immediately turned on.
4. Block Heater Should cycle ON-OFF every 20 sec to 2 min. On continuously until
up to temp.
5. Conv Heater Should cycle ON-OFF every 20 sec to 2 min. On continuously until
up to temp.
6. Reaction Cell Heater Should cycle ON-OFF every 20 sec to 2 min. On continuously until
up to temp.
9.3.6. Ozone Generator
The ozone generator subsystem consists of a permeation drier, flowmeter, transformer -
generator assembly, and driver board. The location of the components is illustrated in Figure 9-7.
Ozone is generated by drying ambient air, then passing the air between two electrodes that have
a large oscillating electric field generated by a high voltage transformer.
The generator cartridge - transformer assembly is potted to eliminate corona and increase safety.
The module cannot be disassembled.