Common Problems And Solutions In The Use Of DC Stabilized Power Supply
19 Nov 2025
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DC regulated power supplies are prone to various issues during use, such as abnormal output, false triggering of protection mechanisms, and adjustment failures. These problems are mostly related to wiring, internal components, and load matching. Below are common high-frequency faults and their corresponding detailed solutions, integrating the common fault scenarios of multiple devices:
1. No Output or Low Output Voltage
- Common Causes: Input voltage is outside the device’s rated range; power cord is loosely connected or fuse is blown; internal rectifier diodes are damaged or switching transformers perform poorly (causing abnormal energy conversion); 300V filter capacitor fails (reducing the power supply’s load capacity, leading to a sharp voltage drop when connected to a load).
- Solutions: First, check if the power cord is firmly connected and use a multimeter to verify that the input voltage meets requirements. Replace the fuse with one of the same specification if it is blown. For internal component issues: replace damaged rectifier diodes and failed filter capacitors. If the switching transformer is confirmed faulty, contact professional personnel for maintenance or replacement of parts.
2. Excessively High Output Voltage
- Common Causes: Faults in feedback loop components (e.g., optocouplers, operational amplifiers) leading to failure of voltage regulation; sampling resistors are out of tolerance or open-circuited (failing to accurately feed back output voltage signals); damage to components in the voltage regulation control circuit (e.g., TL431, power control chips) breaking the normal operation of the voltage closed-loop control circuit.
- Solutions: Inspect components in the feedback loop and voltage regulation control circuit one by one. Replace faulty optocouplers, sampling resistors, or TL431 chips. Before replacing components, power off the device and take electrostatic protection measures to avoid secondary damage to other parts.
3. Unstable Output Voltage
- Common Causes: Frequent and significant changes in load current (exceeding the power supply’s response speed); fluctuations or interference in the input power supply (transmitted to the output terminal); aging of internal capacitors, parameter changes of resistors, or environmental temperature variations (altering component characteristics); failure of the cooling fan (causing abnormal internal temperature and affecting the voltage regulation circuit).
- Solutions: Minimize the amplitude of load fluctuations or replace the power supply with a faster response speed. Install a filter circuit on the input side to reduce grid interference. Replace aging capacitors and resistors with abnormal parameters. Clean dust from heat sinks, repair or replace faulty fans, and place the power supply in a well-ventilated environment to avoid high-temperature impacts.
4. Excessive Output Ripple
- Common Causes: Filter capacitor capacity degrades or fails (failing to effectively filter AC noise); rectifier diodes perform poorly (reducing rectification efficiency); the power supply operates long-term under high load (near its rated load, exceeding the stable working range).
- Solutions: Replace filter capacitors with larger capacity or better performance; parallel capacitors can be used to improve filtering effectiveness. Replace rectifier diodes with poor performance. Reduce the load appropriately to ensure the load power does not exceed 80% of the power supply’s rated output capacity, lowering the probability of ripple generation.
5. Frequent Triggering of Overload Protection
- Common Causes: Load short circuit or excessive load power (causing output current to exceed the power supply’s rated value); overcurrent protection threshold is set too low (mismatching actual load requirements); internal temperature sensor of the power supply is abnormal (falsely detecting high temperature and triggering associated overload protection).
- Solutions: First, disconnect the load, inspect and repair load short circuits. If the load power is excessive, replace it with a high-power power supply suitable for the load. Readjust the overcurrent protection threshold according to load requirements. Check if the temperature sensor is normal; replace it with a sensor of the same model if faulty.
6. Inability to Adjust Voltage or Current to Target Values
- Common Causes: Confusion between Constant Voltage (CV) and Constant Current (CC) modes (e.g., forcing current adjustment in CV mode or blindly increasing voltage in CC mode); current adjustment knob is turned to the zero position (preventing voltage increase even under no-load conditions); incorrect selection of coarse adjustment gear (e.g., selecting the 10V gear when 12V output is required, resulting in failure to reach the target voltage).
- Solutions: Switch to the correct mode based on requirements (adjust voltage in CV mode, adjust current in CC mode). Turn the current adjustment knob clockwise to more than 1/4 of its range. When adjusting voltage: first select the matching coarse adjustment gear, then fine-tune with the fine adjustment knob. Disconnect the load before switching coarse adjustment gears.
7. Device Overheating with Abnormal Noise
- Common Causes: Poor heat dissipation due to dust on heat sinks or stopped cooling fans; high ambient temperature with poor ventilation (preventing heat dissipation); loose internal components (causing mechanical vibration); aging or faulty components (e.g., filter capacitors, transformers) leading to electromagnetic interference and vibration noise.
- Solutions: Regularly clean the heat dissipation system and repair or replace faulty fans. Move the power supply to a cool, well-ventilated area away from direct sunlight. After powering off, inspect internal components: tighten loose terminals and parts, replace aging or faulty components (e.g., capacitors, transformers). Additionally, install filters on the input and output terminals to reduce electromagnetic interference.
Choosing a high-performance, high-quality DC regulated power supply (such as KUAIQU’s R-SPS series and SPPS-K series) can significantly reduce the occurrence of the above faults from the source. Such power supplies typically use industrial-grade high-quality components (e.g., military-grade resistors, high-temperature-resistant capacitors, high-precision sensors) and feature enhanced voltage regulation feedback loops, multi-layer protection mechanisms, and efficient heat dissipation systems in their circuit design.
Recommended high-performance and easy-to-use dual channel DC stabilized power supply——SPPS305-2KD
For more high-quality products, please follow the official website of KUAIQU: KUAIQU DC Power Supplies for Labs & Industry-High Precision & Reliable – KUAIQU Instrument Store.