Input and Output Wiring
7/99 9782 Series Conductivity/Resistivity Analyzer/Controller - Operator’s Manual 6-9
6.4.2 Disconnecting RC Arc Suppression Circuits
Introduction

Relay contacts are protected by RC arc suppression circuits. Alternating current leakage through

these circuits may be sufficient to trigger very light ac loads such as neon bulbs, PLC logic

inputs, continuity testers, etc. If this leakage cannot be tolerated, the suppression circuits may be

disconnected as described below.

Procedure

Follow the procedure in Table 6-5 to disconnect the RC arc suppression circuits.

Table 6-5 Procedure for Disconnecting RC Arc Suppression Circuits
Step Action
1 Turn off the power to the Analyzer/Controller. More than one switch may be required
to remove power.
2 With the power off, open the case:
• Grasp the bottom center portion of the front bezel and pull it downward and toward you
slightly to disengage the bottom of the bezel from the edge of the case.
• Lift the bezel gently to disengage it from the top edge of the case.
• Swing the bezel to the left. (The bezel and display assembly is mounted on pivot arms.)
The safety cover with its warning label will be visible.
3 With the power off remove the safety cover by removing the single screw holding it in
place.
4Disconnect and tag all wiring from the terminal boards.
5Remove the circuit card retainer clamp at the top of the case. Then slide all the circuit cards
half way out of the case.
6On the right-most vertical printed circuit card (power supply) remove 330 ohm resistors R29
and R30 for Relay 1, and R31 and R32 for Relay 2 from the upper corner of the card.
7If the auxiliary relays are installed, also remove 330 ohm resistors R39, R40, R44 and R45
from those optional assemblies (see Figure 6-1).
8Reconnect all wiring removed in Step 4.
9Replace the safety cover and secure it with the screw.
10 Close the case and power up the unit. Do not apply power until the case is closed.