BUCHI ELS Detector C-650 - Manual (Page 45)

C-650 Operation Manual, Version B 8 Troubleshooting 45
8 Troubleshooting
8.1 General troubleshooting information
The ELSD C-650 Evaporative Light-Scattering Detector is designed to be incorporated into a
Liquid Chromatography system. It is important to note that the detector response reflects the
overall performance of the system, and a “problem” that is seen on the detector output may not
necessarily be a “detector problem”. In almost all cases, there is one and only one cause for a
problem. As an example of this point, if the user observes a noisy baseline, it is possible that the
problem is due to:
• The pump (e.g. a defective check valve).
• The mobile phase (e.g. improper degassing or high residue after evaporation).
• The column (e.g. elution of strongly retained components).
• The nebulizer (e.g. lack of maintenance)
• The detector (e.g. an electronic problem).
It is very unlikely that two problems occur at the same time. The role of the troubleshooting activi-
ties is to determine the cause of the problem. In the following, we assume that the operator has
already determined that other components of the system are operating in an appropriate way.
Do not disassemble the nebulizer. Disassembling the nebulizer will destroy it and this will void
the warranty.
NOTE
The control panel and device electronics do not contain any replaceable components. If the
suggestions provided in this chapter do not remedy the problem, contact your local distributor.
If the digital display does not illuminate when the detector is powered up, turn the unit off and in-
spect the main fuses. If necessary, replace the fuses with some of the same rating as the original
ones for all 115 V and 230 V units. The fuses are located inside the main power module on the
rear panel (Fig 5.7). A set of replacement fuses is delivered in the starting kit.
If the fuses are not blown or if the replacement fuses blow up again, contact your local distributor.
8.2 Initial troubleshooting activities
• Make sure that the device and all components of the detector are grounded to a true
ground.
• Check to ensure that the liquid level in the siphon is appropriate, and there is no liquid pool-
ing close to the evaporation tube inlet.
• Check that the gas pressure is sufficient and stable. The selected pressure for most applica-
tions is 2 bar (29 psi). Pressure above 4.5 bar (67 psi) can damage the pressure sensor. The
gas filter should be clean and in place. Only use gas free of oil residue.