Analysis and elimination of common faults of PH meter
In practical work, the aging of equipment components, improper operation methods and unstable power supply voltage will all lead to the failure of PHS-3B-S pH meter, which will bring difficulties to correctly obtain acid rain observation data. It is necessary for observers to diagnose and analyze the failures in time and accurately, so as to ensure the normal development of acid rain observation business.
(1) The power supply is turned on, but the possible reasons and treatment methods are not shown:
A. the fuse is broken and should be replaced;
B. If the power supply or transformer is broken, it should be repaired or replaced;
C. if the instrument circuit fails, it should be sent for repair.
(2) The pH value cannot be adjusted to 7.00 by "positioning". Possible reasons and treatment methods:
A. When the supplementary liquid of the composite electrode dries up, add 3M potassium chloride solution or replace the electrode;
B. The composite electrode fails and should be replaced;
C the internal potentiometer is broken and should be repaired or replaced.
(3) If the "slope" cannot be adjusted to pH 4.00 or pH 9.18, the possible reasons and treatment methods are as follows:
A. The composite electrode is aged and its performance is degraded, so it should be replaced;
B. The internal potentiometer is broken and should be sent for repair and replacement.
(4) When measuring 4)pH value, the reading is unstable, its possible reasons and treatment methods:
A. if the k value of the water sample is too low (e.g. lower than 10μS/cm), the equilibrium time shall be appropriately prolonged;
B. The internal resistance of the composite electrode is too high, and its service life has reached, so it should be replaced;
C. If the composite electrode plug (seat) is damp or polluted, it should be wiped with 95% alcohol after shutdown and dried before use;
D. If the power supply voltage is unstable, or the grounding wire touches * *, turn off the power supply and weld the grounding wire firmly, and then turn on the power supply for measurement after the voltage is stable.
(5) During "automatic" compensation, the number overflows or the displayed value is unstable, the possible reasons and treatment methods:
A. The temperature measuring probe is not connected or broken, so it should be connected or replaced;
B the temperature compensation selector switch is broken and should be sent for repair or replacement;
C. The internal disconnection of the temperature probe jack should be sent for repair;
D. if the instrument circuit fails, it should be sent for repair.
