Switches, power is actually a power source that can effectively stabilize the output voltage. So if we don't have good maintenance for it, switch power can easily cause damage, especially 12v. In fact, the maintenance of the 12v switch was always felt to be not complicated. And this occasional problem, we always need to learn to deal with it. Today, it is here to bring you a method of repair of the 12v switch, and it is hoped that you will enjoy it。
1, 12v switch power insurance for burning or blowing up
Mainly checking the large filters on 300 v, the electrical caps, the two polar tubes on the current bridge, and the switch, problems with interference circuits can also lead to fire and blackouts. And what needs to be noted is that the safety burns that result from the plugs usually burn current detection, resistance and power control chips. Negative temperature coefficient thermally sensitive resistance is also easily burned with insurance。
Two, 12v switches, no output, safes
This is an indication that the switch power is not working or is protected. First, to measure whether the power control chip's start-up foot has a start-up voltage, or, if no or too low start-up voltage is available, to check whether the element that activates the resistance and activates the outside of the foot is leaking, at which point, if the power control chip is normal, a failure can be detected quickly。
If there is a start-up voltage, the output end of the control chip is measured for any high- and low-level jump at the start of the engine, indicating that the control chip is bad, the peripheral oscillating circuit element or the protection circuit is in question, the control chip is replaced and the peripheral component is then checked; if there is a jump, the switch is generally not good or damaged。
3, 12v switch power has an output voltage, but an output voltage is too high
This failure usually results from steady-pressure sampling and steady-pressure control circuits. In direct-flow output, sample resistance, error sample amplifiers, such as tl 431, optical coupons, power control chips, etc., together constitute a closed control loop, and any problem leads to higher output voltage。
Four, 12v switch power output is too low
In addition to steady voltage control circuits, which cause low output voltage, there are a number of other reasons for low output voltage:
A. Switch power loads containing short circuit failure (especially dc/dc converter short circuits or poor performance, etc.), at which point all loads of the switch power circuits should be disconnected to distinguish between the switch power circuits and the load circuits. If the power output of the circuit is normal, it indicates that it is overloaded; or if it is still abnormally indicative of a failure of the switch power circuit。
B. Output voltage end-to-flow diodes, filter-capacitation failure, etc., can be judged by substitution。
C. Decline in the performance of the switch pipe, which inevitably results in the failure of the switch to properly conduct, increases the internal resistance of the power supply and reduces the carrying capacity。
D. Switches, transformers, bad, causing not only a drop in output voltage, but also a lack of incentives for switches and repeated damage to switches
E. 300v filtering capacity is poor, resulting in power belt load capacity, which drops when the load output voltage is carried。
Because of its small and efficient characteristics, the switch is well applied to many electronic devices. In fact, if there's a problem with the 12v switch, if we don't repair it in time, it's difficult to make sure that the 12v switch is safe. At the same time, it must be noted that the lack of regular maintenance of the 12v switch power also affects the quality of use of the 12v switch power. At the same time, we need to be careful as we repair the 12v switch, looking carefully at the 12v switch and whether there are any other minor problems, and then we need to work together to avoid more problems in the future。
