Specifications

M
AINTENANCE AND
T
ROUBLESHOOTING
748410-A
August 1999
30
Chemiluminescense Detector Analyzer Module
Rosemount Analytical NGA 2000
4
4.5 O
ZONATOR
Refer to Figure 4-1.To replace the ozonator, remove the two large straps and all tie-wraps,
and disconnect the one electrical connection. Reassemble in reverse order.
4.6 P
RINTED
C
IRCUIT
B
OARDS
All four printed circuit boards can be replaced, if necessary. Refer to Figure 4-1 for location
of the Driver, Power Supply, Signal and Computer Boards.
To remove any PCB (
except
the Computer Board), disassemble the enclosure side first.
Ribbon and other cables are long enough to allow the entire side to be folded out from the
remainder of the components. This makes PCB removal much simpler.
Tag each connector and its location before disconnecting any wiring. This helps in
reassembly.
4.7 D
ETECTOR
D
ISASSEMBLY
Refer to Figure 4-3.
Reaction Chamber Removal
Disconnect the stainless steel tubing lines at the Gyrolok fittings. Remove the (4) nuts
holding the Detector Assembly to the chassis. Disconnect the plug from connector J1 on
the Signal Board and remove the assembly from the chassis.
Care should be taken to avoid getting heatsink compound on optical surfaces.
If this substance is removed during the disassembly process, a
zinc-oxide-filled, silicone grease (e.g., Dow Corning 340 or EG&G Wakefield
Engineering's Series 120 Thermal Joint Compound) be reapplied in the
reassembly of this component.
Although the heater and thermostat can be removed to facilitate handling, contact with the
white heatsink compound can be minimized by leaving these items in place. Remove the (2)
screws holding the top plate of the Detector , and move the plate along the wires and away
from the Detector .
Remove the (2) screws holding the tube assembly in place. Hold the tubing with one hand
while inverting the Detector Housing with the other, allowing the Reaction Chamber O-ring
and window to be removed from below.
NOTE