Model 202 Ozone Monitor Manual Rev. J-4
28
Cell temperature reads
low by several 10’s of
degrees.
Absent or loose connection
of temperature probe cable
to circuit board.
Remove top cover and
reattach connector to circuit
board (see Figure 9-3).
Readings are noisy with
standard deviations
greater than 2.0 ppbv.
Lamp output is weak.
Excessive vibration.
Flow path contaminated.
Remove top cover and
check lamp connection to
circuit board (see Figure 9-
3). Run Lamp Test from
menu. If photodiode
voltage is less than 0.7 V,
replace lamp.
Provide additional vibration
insulation for the instrument
such as a foam pad.
Clean flow path with
methanol according to the
Cleaning Procedure (see
Tech Note 018
).
Analog output is
constant or does not
track front display.
Cable not properly
connected between analog
output BNC and circuit
board.
Wrong scaling factor
selected in Menu.
Remove top cover and
reconnect cable between
analog output and circuit
board (see Figure 9-3).
Check and reset analog
output scaling factor in the
Menu.
Select switch does not
work.
Cable not properly
connected between select
switch and circuit board.
Remove top cover and
reconnect select switch
cable to circuit board (see
Figure 9-3).
Serial port does not
work.
Cable not properly
connected between serial
port 9-pin connector and
circuit board.
Wrong serial cable used.
Remove top cover and
reconnect serial port cable
to circuit board (see Figure
9-3).
A
“straight through” serial
cable is provided. Some
data collection devices
require a ”cross over”
cable in which pins 1 and 3
are exchanged between
the two ends of the cable.
Use a “cross over cable or
additional connector that
switches pins 1 and 3.
