After analyzing three different PCB revisions (common in Chinese industrial supplies), here is the . Note that component labels (R1, C2, etc.) are generic, but values are specific to the 24V/1.1A output.
The "1.1A" rating is critical. This is not a 1A or 1.5A supply. Overloading it beyond 1.2A will cause the transformer to saturate or the primary switching MOSFET to overheat. f4901 1.1a 24v schematic
On these laptop boards, this component is often a fast-acting fuse protecting the backlight circuit or a specific low-power voltage rail. F4901 (Fuse 4901) Current Rating: 1.1 Amps (1.1A) Voltage Rating: 24 Volts (24V) Common Use: Backlight power protection for LCD/LED panels. Troubleshooting with the Schematic After analyzing three different PCB revisions (common in
Always respect the 1.1A limit. Overload protection in this design is primitive—it relies on the primary current sense resistor and transformer saturation. Push it to 1.5A, and you will permanently damage T1, requiring a full rewind or replacement. This is not a 1A or 1
