Hach-Lange POLYMETRON 9240 Operator Manual - Manual (Page 115)

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Section 10 Troubleshooting
10.1 General faults
WARNING
Before opening the instrument, ensure the power supply has been switched off.
Table 11 General Faults
MALFUNCTION POSSIBLE CAUSE REMEDIES
No display on the screen.
No power.
The instrument is not properly connected.
Check power and connection.
Defective fuse.
Replace fuse (see Fuse replacement on
page 104 for details).
Cable connecting power with CPU board
is not properly plugged in.
Check plugs.
Connection between CPU board and
PSU module is not correct.
Check plugs.
Short circuit in power supply board. Visually check power supply.
Hardware is defective. Call the Service Technician.
Display is incorrect.
Malfunctioning CPU board or software is
defective.
RESET the instrument by temporarily
interrupting the power (5-10 secs). Call the
Service Technician.
Keyboard does not operate; all
keys are inactive. CPU malfunctioning, external
interferences.
Check the keyboard connection plugs. If there
is still no response, RESET the instrument by
temporarily interrupting the power (5-10
seconds). Check each key again. If there is no
change, call the Service Technician.
Measurement unstable
(standard applications).
Electrode not properly connected. Check the electrode is properly connected.
Interferences.
Look for any chemical, temperature or pressure
source of interference.
Measuring cable shielding is not well
connected.
Check and connect.
No electrolyte. Refill the electrolyte solution.
Incorrect conditioning.
Verify conditioning reagent bottle is not empty.
Verify tubing between conditioning bottle and
overflow is correctly connected.
Verify if solenoid valve for overflow vessel is
blocked and replace it if needed.
Defective measurement board. If problem persists, call the Service Technician.
Measurement unstable
(cationic applications).
Incorrect conditioning.
Adjust the pH in the measuring cell until it is
between 11 and 11.2.
Verify if solenoid valve for overflow vessel is
blocked and replace it if needed.
Defective pump.
Verify in a beaker of water that the pump is
working correctly. Flow rate should be around
250 cc/min.
No diisopropylamine. Replace the bottle of diisopropylamine.
No electrolyte. Refill the electrolyte solution.
Electrode not working.
Change the electrode and verify the problem is
fixed.