Uploaded February 2026 | Updated September 2026, 1 week ago

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Analyzing a faulty fast 120W GaN USB charger from Novoo with 2x USB-C and 1x USB-A ports. A diagnosis and a temporary fix. Explaining how it works. A lot of measurements and oscilloscope waveforms. A simplified reverse engineered schematic. An active PFC, a flyback power supply with a synchronous rectifier and synchronous buck regulators. Switching transformer autopsy.

The DMT-99 multimeter:
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The FNB58 USB tester:
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The HRM-10 internal resistance tester:
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The 2-channel 180MHz oscilloscope:
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My DIY test load:
danyk.cz/zatez2_en.html

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danyk.cz/avr_ring2_en.html

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