Six cases of FJ-2003/50 type immune counter troubleshooting

Fault 1: Start burning general insurance.

Maintenance steps and solutions:

(1) Check if the connectors or plugs and sockets of the AC 220V power supply are short-circuited.

(2) Whether the coil of the power supply filter and the filter capacitor are short-circuited to ground.

(3) Whether the connector of the internal AC connection of the instrument or the switch connected to it is short-circuited.

(4) Whether the power indicator on the power supply detection board on the main unit is short-circuited or short-circuited to ground.

(5) Whether the primary or secondary winding of the main transformer in the internal control box of the main unit is short-circuited.

(6) Whether the AC 110V power supply of the sample changer is short-circuited.

(7) Whether the rectifier silicon stack of the low-voltage power supply is short-circuited.

Fault 2: Do not count.

Maintenance steps and solutions:

(1) Whether the connection of each connection is correct, whether the connection is open or shorted.

(2) Whether the switch of the high voltage power supply is turned on.

(3) The adjustment of each working point and the correctness of each switch position, especially when the amplifier polarity switch is at "+", it is not counted.

(4) Whether the operating program is correct and whether the preset subtraction is too large.

(5) Whether the power supply of each group of low voltage is normal.

(6) Is the high voltage power supply normal? A normal high voltage can hear a monotonous "click" sound.

(7) Turn the main amplifier "+" and "one" polarity switch to observe whether the recording system has counted. If there is a count, the plug-in after the main amplifier works normally, and the fault is usually in the preamplifier; if there is no count, the plug-in after the main amplifier is faulty (including the main amplifier).

Fault 3: The count is unstable.

Maintenance steps and solutions:

(1) First test whether the grid voltage is stable. If equipped with an AC regulated power supply, the output voltage of the regulated power supply should be tested for stability.

(2) Check if the output voltage of the low voltage power supply and the high voltage power supply is stable. For low-voltage power supplies, it sometimes takes a long time to observe. At this time, the three-meter meter pen can be inserted into the corresponding low-voltage power supply detection hole to observe the change. For the high-voltage power supply, the high-voltage oscillation sound can be used to judge whether the high-voltage operation is normal. The normal high-voltage oscillation sound should be a separate “beep” sound. When the fluctuation occurs, the high-voltage power supply is faulty.

(3) Check if the selection of high pressure working point is appropriate.

(4) Whether the baseline recovery circuit of the single channel analyzer is drifting, and whether the domain value voltage output by the domain modulation circuit is stable.

(5) The interrupted self-oscillation of the main amplifier may also be the cause of the instability of the count.

(6) Unstable counting sometimes does not necessarily cause problems with the instrument, and sometimes it is caused by the operator's misoperation. For example, the sampler is not allowed, the supernatant is not consistently extracted. Sometimes the test tube is not in place and the count is reduced.

Fault 4: The background count is high (the counting efficiency is normal) .

The cause of this phenomenon is generally that the measurement well is contaminated. It can be solved by alcohol cleaning or replacing the nylon protective cover and nylon ejector.

Nylon protective cover replacement steps and methods:

(1) First remove the black metal cover behind the plexiglass cover and remove the sample code lamp holder.

(2) Remove the sample tray and sample tray.

(3) Remove the fastening screws of the nylon sheath of the measuring well and pull out the nylon sleeve.

(4) Replace with a new nylon boot and reinstall in reverse order.

(5) When installing the sample tray, pay attention to adjust the four fastening screws of the fixed sample tray, align the sample tray with the measuring well, and calibrate with the collimator. After confirming the fit, tighten the sample tray fastening screw.

Steps and methods for replacing the nylon ram: The nylon ejector is mounted on the top of the lifting rod and adjusts the height of the nylon ram to ensure that the lifting rod is parallel to the sample table when it is in the upper position. Special attention should be paid to the fact that the lifting rod is higher or lower than the sample table, which will cause the tube or horizontal rotation failure. In severe cases, the horizontal motor will be burnt.

(1) First remove the shaft pin connecting the lifting rod and the lifting plate.

(2) Loosen the two top wires on the lifting plate and the vertical motor spindle and remove the lifting plate.

(3) Remove the lifting rod, remove the contaminated nylon ejector rod, and clean the lifting rod with alcohol.

(4) Install the new nylon ejector on the top of the lifter and adjust the nylon ram to the approximate position and tighten the nut.

(5) Insert the lifting rod into the measuring well in the reverse order, and install the lifting pin and the lifting pin and the lifting pin to connect the shaft nail. At the same time, pay attention to adjust the lifting rod to be parallel with the sample table when it is in the upper position.

Fault 5: The horizontal drive is not smooth.

The main reason for this phenomenon is that the guide wheel of the horizontal transmission mechanism itself is not flexible. The bearings in the guide wheels are greased during installation. Due to the long-term operation, the butter is degraded and the steering wheel is not flexible or can not be rotated at all, resulting in the entire horizontal rotation not smooth.

Maintenance steps and solutions:

(1) First, turn each guide wheel one by one to check whether the rotation is flexible, find the guide wheel that is not flexible, and remove it.

(2) Pull the removed guide wheel out with a screwdriver to clean the grease, and add gasoline to clean it, while turning it back and forth repeatedly until it is flexible. Then add the right amount of butter to reinstall the guide wheel.

When the guide wheel is installed, the sample chain is not easily pulled too tight.

Fault 6: The counting efficiency is low and the background count is high.

There are generally two possibilities for this phenomenon: one is whether the system's working state selection is normal. The other is that the NaI scintillation crystal deliquescent turns yellow, which deteriorates the performance of the crystal or the aging of the photomultiplier tube.

Maintenance steps and solutions:

(1) Check if the main amplifier working status setting is correct.

(2) Check if the analyzer's working status is set correctly.

(3) Check if the debugging of the high voltage working point is correct.

(4) When the photomultiplier tube is aged, the noise is greatly increased and the efficiency is lowered. At this point, the working high voltage can be reset to solve the problem, otherwise the photomultiplier tube should be replaced.

(5) Remove the photomultiplier tube and observe whether the NaI scintillation crystal turns yellow (good crystal should be colorless and transparent). In the case that all other systems are normal, the crystal is mostly yellow, which causes the instrument to have low counting efficiency and high background count. This situation usually takes a long time to change, and the count rate gradually decreases without sudden changes.

( Nanhua University, Medical Equipment, Roh Moo-hyun )