Aquametrix 2200D Dissolved Oxygen Controller/Analyzer User Manual - Manual (Page 25)

Model 2200D/P91 Page 23
b) The power supply circuit board is fastened to the back of the enclosure by four
screws, remove the screws and the board is free. Reverse the procedure to
mount a replacement board.
c) The microprocessor circuit board is located on the swing-out assembly behind
the door. Swing the assembly out, lift it up to unseat the lower hinge pin (the
upper hinge pin is spring loaded.) The assembly is now free. The circuit board
is fastened to the front panel by three screws. Remove the screws to release
the circuit board.
9.4 Sensor Fault
9.4.1 If the membrane of the sensor cartridge is pierced, the alarm relay contacts will
close and the FAIL LED (For Model 2200D-X-1) and STATUS LED (For Model
2200D-X-2) will be illuminated. However, it may be difficult to see the leakage with
the naked eye. A slight pressure on the membrane with a finger will produce a drop
of liquid. The cartridge must be replaced. See Section 9.4.3.
9.4.2 With operating time silver oxide will build up on the anode (silver wire). When the
anode becomes brown as a result of the deposit, it is time to replace the sensor
cartridge.
9.4.3 To replace the sensor cartridge, unscrew the retaining nut, remove and discard the
spent cartridge and replace with a new cartridge. AquaMetrix Part No. P91-D.
9.5 Relay Replacement
9.5.1 The relays are plugged into the power supply board just above the terminals. Be
sure all the power including independent power to the relay is off. Unplug the relay
in question and replace with a new relay. AquaMetrix Part No. 17-38.