The summary of ’24V 1000W power supply – what's inside’

This summary of the video was created by an AI. It might contain some inaccuracies.

00:00:0000:15:40

The video focuses on the detailed examination and disassembly of a 24V 1000W switching power supply module purchased from eBay. The presenter starts with an overview of the power supply's external features, including its connections, voltage selector, and the noticeable shipping damage. Delving inside, they analyze the internal components, pointing out key parts such as interference filters, relays, electrolytic capacitors, heat sinks, and transformers. There is a particular emphasis on the cooling mechanisms and the configuration of the transistors and circuit board.

Further, the presenter describes the layout and functionality of both the primary and secondary sections of the power supply, noting similarities to a 600W model and identifying the topology as 'tu switch forward'. They remark on the safety design features like isolation distances and slots in the circuit board, although they also point out areas where the design could be improved for better safety and performance.

Concerns are raised regarding the quality and potential reuse of components, such as transistors and capacitors, potentially sourced from e-waste. The video concludes with plans for further testing and analysis of the components, including verifying capacitor authenticity and examining the transformer. The presenter also thanks patrons for their support and hints at future content and detailed component autopsies.

00:00:00

In this segment of the video, the presenter examines a large switching power supply module from eBay, specifically a 24V 1000W model. Key points include its terminals for live, neutral, ground, positive, and negative connections, a potentiometer for adjustment, and a warning that advises not to exceed 80% of the rated power. The voltage selector can switch between 110V or 220V, with the input voltage noted as 110V or 220V ± 15%, and the output as 24V DC at 41.7A. The unit arrived damaged, with bent corners and mounting holes, likely due to mishandling during shipping. The presenter proceeds to open the module, revealing the internal components, including a loose insulation shield and large capacitors, suggesting a solid build compared to a 600W model, and a fan placed on the side.

00:03:00

In this part of the video, the speaker examines the internal components of a power supply, describing various elements such as interference filters, relays, electrolytic capacitors, heat sinks, and transformers. They highlight the presence of a DC brushless fan and its connection to a 12-volt output despite the power supply’s 24-volt rating. The speaker details the input connections, including life, neutral, and ground, as well as the fuse, interference filter, common mode suppression inductor, and capacitors. They note the NTC thermistor for inrush current limitation and the configuration of the bridge rectifiers and voltage switch. The primary side of the power supply features large smoothing capacitors. They also discuss the control circuitry mounted on a small inserted board and proceed to remove the circuit board to closely inspect the mounting and heat dissipation mechanisms, noting how various components are secured and cooled.

00:06:00

In this part of the video, the presenter discusses the functionality and placement of a heat sink on transistors. The heat sink is mounted on the side of the transistors, although it’s generally more effective when attached to the metal backside. They note that the transistors might not be sufficiently cooled from this side, though the heat sink helps in pressing the transistors evenly. The presenter also removes a screw from the center of the board, allowing it to be taken out, revealing a single-sided board with no components or tracks on the opposite side and a corner cut out for possibly better insulation. Further exploration of the board reveals various components such as a voltage regulator chip, electrolytic capacitors, SMD resistors, capacitors, transistors, a zener diode, and additional resistors. The fan was also disconnected, revealing that it was glued in along with an inductor.

00:09:00

In this segment of the video, the speaker describes the components and layout of a power supply, highlighting their similarities to a 600-watt power supply model. The key points include the presence of:

1. **Primary Section**:
– Current sensing resistors, gate driving transformer, big diodes, snapper capacitors, gate resistors, pull-down resistors, and protective zeners.
– Identified topology as a ‘tu switch forward’.

2. **Secondary Section**:
– Isolated from the primary section by an optocoupler and a big switching transformer.
– The transformer has distinct primary, auxiliary, and secondary windings.
– Rectification diodes on a heat sink, consisting of four double diodes in parallel.
– An output inductor on an iron powder core leading to electrolytic secondary smoothing capacitors (2200 microfarads, 50 volts) and snubber networks.
– Voltage sensing circuitry with a 431 voltage reference, resistors, capacitors, adjustment potentiometer, and an indication LED.
– Discharging and loading resistors for the capacitors.

The segment also notes that some circuitry is omitted, shows the connector for the fan, and terminates with a review of the isolation distances on the board, ensuring safety through design features like a slot for isolation.

00:12:00

In this part of the video, the speaker examines a circuit board, noting that the distance between the primary and secondary sides seems adequate but could be larger for added safety. They observe odd track switching from the optocoupler, which appears in a safety-critical area instead of a less critical one. The board is very dirty, with clear signs of liquid spills. The primary switching transistors have different batch numbers, suggesting they might be recycled from e-waste. The electrolytic capacitors seem reused, with visible dents indicating they were likely disassembled from other devices. Additionally, the speaker suspects fake labels on the capacitors. In future segments, the speaker plans to test the components, conduct an autopsy on the transformer, and check if the windings are copper or aluminum. They will also measure the capacitance and impedance of the capacitors and examine their authenticity by removing the heat shrink and plastic tops.

00:15:00

In this part of the video, the creator wraps up by thanking their patrons on Patreon for their support and invites viewers to become patrons to receive early access to videos. The creator mentions the links to their Patreon and Instagram in the description. They tease upcoming content including testing a power supply, potentially sharing its schematic, performing an autopsy of some components, and examining an IKEA battery charger.

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