Example of AC adapter for electronic instruments, audio and visual equipment

We introduce a custom development case of an AC adapter specialized for electronic instruments, audio equipment, and video devices. At UNIFIVE, we are highly rated by many major manufacturers in fields that demand high quality and technical capability, starting with noise countermeasures and compliance with various safety standards.

About AC/DC Power Adapters — Desktop & Wall-Mount used in electronic musical instruments

Safety standards applied to electronic musical instruments

AC/DC Power Adapters — Desktop & Wall-Mount for electronic musical instruments, audio equipment, and video devices must comply with international safety standards such as IEC/EN 60065. These standards apply to both linear and switching types and are essential for ensuring the safety and reliability of the Products.

Main differences from IEC60950 (compared to communication equipment)

• LPS requirements: Mandatory evaluation measurements for communication equipment (IEC60950), not required for audio equipment (IEC60065).
• X electrolytic capacitor: Residual voltage < 37% one second after power off in communication equipment, peak 60V or less two seconds after power off in audio equipment.
• Leakage current: Communication equipment: 0.25mA, audio equipment: 0.5mA
• Operating temperature: Communication equipment: 35°C, audio equipment: 45°C (Subtract -10K from component rating in both cases)
• Oil Test (Softening Test): A test specific to audio equipment where materials are immersed in oil and the temperature is gradually raised up to 175°C for verification

Oil test method and evaluation criteria

Test method (reference):
Immerse the target part in an oil bath and start at an initial temperature of 100°C. Raise the temperature by 50°C every hour, and conduct the final evaluation at 175°C.

Pass criteria: Case dent depth must be less than 0.1mm.

This test may use up to four different methods.

*This information is based on past performance as of December 1, 2020.

Recovery case from safety standard failure

Contributing to mass production with flexible support and technical proposals

In a development project for a Products AC/DC Power Adapters — Desktop & Wall-Mount commissioned by a major manufacturer, S Corporation, the Products initially failed safety standard tests. The main reason was that the polycarbonate (PC) resin used in the case failed the oil test under UL standards.

In response to this issue, UNIFIVE worked closely with S Corporation to analyze the cause in detail. As a result, we proposed a minimal yet highly effective improvement that involved switching only a limited resin area around the AC pin to a different material without changing the overall design. This approach led to successful retesting and smooth transition to mass production of the Products.

Through this case, we deepened our understanding of the thermal impact and deformation risks associated with using the same resin, and established methods to ensure reliability by appropriately combining different resins. This know-how is now being applied to respond quickly and accurately to similar cases.

UNIFIVE not only specializes in custom development of AC/DC Power Adapters — Desktop & Wall-Mount/power supplies, but also provides proven solutions for issues related to safety standards and design. Feel free to even if you're just considering an idea. With solid experience and responsiveness, we powerfully support your problem solving.

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