The PCR machine is an instrument that is used very frequently in the laboratory, so the failure rate is also relatively high. The main faults of the PCR machine are as follows:
1, refrigeration semiconductor failure
2, temperature sensor failure
3, the control board is faulty
4, power board failure
5, hot cover failure
6, software failure
7, other faults
The following is a brief introduction to the impact of the maintenance of these faults on the performance of the instrument.
1, refrigeration semiconductor failure
Since the refrigerated semiconductor is semi-manually produced, the performance of each piece of refrigerated semiconductor is different. Refrigerated semiconductors used in the production of PCR machines are all required to be paired. Generally, large manufacturers will select a group that is very close in performance after testing the performance of a larger number of refrigerated semiconductors.
That is to say, after the refrigeration semiconductor fails, all of the groups should be replaced. But most repairs only replace one of them, which will result in uneven temperature (such as four cooling semiconductors with only one sensor like the 2720) or uneven temperature rise and fall (like the Dongshenglong 811 PCR instrument). There are three cooling semiconductors with three sensors).
The replacement of three cooling semiconductors also involves the assembly of the entire temperature control module, which is a technical activity. To ensure the temperature performance of the instrument, the assembly process requirements are very high, and some require special tools or fixtures. Poor assembly can affect temperature uniformity, ramp rate, and even instrument life (internal overheating, water ingress, etc.). This is why the manufacturers of PCR instruments are asking for repairs.
2, temperature sensor failure
The temperature sensor generally achieves high thermal conductivity by means of a thermal grease or a thermally conductive adhesive. At least the following points should be noted for replacement: the same type of temperature sensor of the same brand; the same thermal conductive material (silicone grease or curing adhesive) as the original one to ensure the same heat transfer efficiency; the same or similar temperature measurement and calibration method as the manufacturer. When the temperature sensor is replaced at the same time, most of the instruments have to disassemble the entire temperature control module, so it is best to complete the assembly by the manufacturer.
3, the control board is faulty
Control panel maintenance is mainly to pay attention to the same type of components as the original factory. If the repair involves a circuit associated with the temperature sensor, a temperature calibration is required.
4, power board failure
Power board repair is also mainly to pay attention to the same type of components as the original factory. Poor maintenance has little to do with instrument temperature performance, but it is related to the life of the instrument.
5, hot cover failure
Hot cover failures are typically heating device failures or sensor failures. It is best to choose the original heating device, but the assembly is technically sound. The poor assembly will affect the uniformity and life of the thermal cover. The temperature sensor can be used with the same type of components as the original one. However, the installation method of temperature insurance must pay attention to it. Some manufacturers use cylindrical insurance, which is not reliable with the heat cover. It is likely that the hot cover sensor will fail to have the insurance function and cause the hot cover. Exceeding the temperature or catching fire.
6, software failure
Software failures are generally eliminated by updating the software. Generally does not affect the performance of the instrument.
7, other faults
The relationship between these faults and the performance of the instrument is not good.
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