Sewing machine repair electrical control failures are generally what conditions should have?

When a fault detection circuit, gradually narrowing the scope of failure, the following principles should have detected the fault of a few:

(A) first overhaul after inquiry. Before the whole circuit fault detection asked time to carefully failure to the user, what symptom? Does anyone repaired? Then according to use, fault characteristics were analyzed for judgment, hands-on testing.

(2) the first analysis hands. When the whole circuit fault detection, first detailed analysis of the causes of failure under the circumstances to determine failure location, with the right side and then hands-on testing to detect faults. In analyzing the causes of failure, we must understand the whole circuit board works, familiar with the whole circuit diagram, the machine consists of a clear which parts? What is the function? What is the causal link between the well section.

In the whole rationale for guidance, according to the fault phenomena and specific circuit for analysis, judgment, key parts for testing, measuring the location of the fault diagnosis, achieve the purpose of the repair of.

(3) the first inspection after a cold hot check. Detecting means that the whole cooling circuit is not energized visual inspection resistance assay, refers to the thermal detection circuit after power machine checks the current detector comprises a voltage detection method, the interference detection method, the oscilloscope detection. Some power circuit failure Throughout examination, visual, on-line resistance measurement can be directly detected the fault position, after replacing the processor can troubleshooting. If the blind power, may make the whole device trauma suffered more slowly, expanding the scope of failure. Only after a cold check, before electricity checks. Sometimes the repair process, the need to check cold, hot check alternately.