Fault Diagnosis and Elimination of Ultraviolet-Visible Spectrophotometer

Release time：2019-03-19

Ultraviolet-visible spectrophotometer is composed of optical, mechanical, electrical and computer parts. Optical part has the possibility of dampness and mildew to deteriorate its performance, mechanical part has the problem of wear and tear, electronic components have the problem of aging, etc. Therefore, it is impossible for components to never fail, and their optical properties will be damaged by dampness or contamination. If the grating is damped, stray light of the whole machine will increase, and other optical components will be damped, which will reduce the reflectivity and seriously affect the sensitivity of the ultraviolet-visible spectrophotometer. The mechanical parts will be worn and worn because of long-term operation, resulting in wavelength error and influence analysis and measurement. The accuracy of the test; the electronics part, because of the influence of the "bathtub effect of failure of electronic components", will often fail in the front stage of the bathtub effect and the back stage of the bathtub effect, and more frequent failures will occur in about 10 years.



Therefore, no matter what kind of ultraviolet-visible spectrophotometer, no matter which company produces ultraviolet-visible spectrophotometer, temporary failure is very normal and unavoidable. Because there are many reasons for the failure, such as the defect of instrument manufacturing, the influence of environmental factors, improper operation and so on. Therefore, users should master general fault diagnosis and elimination methods.



(1) There is no reaction of the instrument after starting, the main reasons are as follows.



A. No supply voltage (220V AC)



B. Poor contact of power cord



C. Fuse of the fuse at the power switch



(2) Tungsten lamp self-inspection



A. Light shielding. Check for foreign bodies in the sample pool or other objects in the light path to block light



B. Tungsten lamp is broken. Replace it. (Note that clean paper cover should be used before replacing the lamp.)



C. The light source mirror is oxidized and rusted. The surface of the light source mirror is metal coated. It is in humid and corrosive gas environment for a long time. The metal film is easy to oxidize and rust (contact the manufacturer, change the light source mirror)



D. Poor contact between tungsten lamp holder and tungsten lamp holder or between tungsten lamp holder and tungsten lamp holder. The solution is to use small inner hexagons or a word) 9 to fasten separately.



(3) When self-checking wavelength origin, the motor has abnormal noise and self-checking error.



The fault is the screw rod (sine arm crossing the photoelectric switch). The solution is to turn off the power supply, open the cover of the instrument, hand-pull the sinusoidal mechanism coupling shaft, and transfer the sinusoidal arm to the middle position of the screw rod.



(4) On-line self-inspection, the origin location of sample pool is wrong.



A. The sample pool is fixed and the software is multi-pool. Set the software to a fixed pool and reboot for self-check (and vice versa)



B. Loose Connection Plug of Multi-pool Motor



C. Loose Connection Plug of Photoelectric Switch in Multiplex Cell



5) Deuterium lamp positioning errors and wavelength positioning errors in on-line self-test



A. Deuterium lamp is broken, -, replacement



B Light Source Mirror Oxidation Rust



C. The fuse on the lamp power board is fused. The solution is to open the cover of the instrument and replace the fuse on the lamp power board (sometimes behind the instrument).



(6) When measuring samples, the numerical value is unstable.



A. Photolysis of Samples



B. Colorimetric dishes dirty, cleaning colorimetric dishes



C. Glass colorimeter should be used in ultraviolet region, quartz colorimeter should be used.



D. There is a problem with the sample solution. The chemical reaction of some sample components has a certain time course, and the concentration of each component changes with time.



E. The instrument is noisy.



(7) The instrumental stability exceeds the standard.



At present, the measurement of absorbance and transmittance is not stable, the reason is also the instrument noise or the same (6).



(8) Baseline indicators exceed the standard



A. Not enough preheating time



B. The instrument is noisy.



Note: The baseline must be calibrated before making the baseline. The scanning speed is medium when calibrating the instrument baseline. Sometimes the scanning speed is slow when calibrating the instrument baseline, but the high-speed scanning can not be used.



(9) The instrument is noisy.



A. Installation of voltage regulator due to unstable supply voltage



B. Light source mirror oxidation, replacement of light source mirror



C. Light shielding of sample pool should be adjusted appropriately.



D. Without dark current, insert the black block into the sample pool to make dark current.



E. Mirrors in the light path are dirty and need to be cleaned (note: the light source mirror can only be blown by ear wash balls, not wiped by anything)



(10) The instrument cannot be connected with PC



A. RS232 Serial Port or USB Connection Loose, Re-insert, Tighten Two Screws



B. The inconsistency between software and actual COM ports



C. Address may be occupied by other programs. COM port can be replaced to solve this problem.



Serial Port Damage of D.PC



(11) Instruments cannot be printed



A. Parallel port print cable loosened and reconnected



B. Printer model incompatibility



(12) Abnormal printing of instruments, such as disordered codes, etc.



A. Printer model incompatibility



B. The instrumentation software is not working properly. Shut down and reboot to solve the problem.