Before diving into the schematic, we must identify the component labeled "F4901."
If your F4901 module has failed, do not throw it away. Here are the top 5 failure modes mapped to the schematic. f4901 1.1a 24v schematic
+-----------------+
| AC Input (L) |
+--------+--------+
|
F1 (Fuse 1.5A Slow)
|
+----+----+
| L1 (Common Mode Choke)
+----+----+
| |
C1 (X2) |
| |
+----+----+
| Bridge Rectifier (DB1) |
+----+----+
| |
C2 (100uF/400V)
|
+---+---+
| R2 (Startup Resistor - 150k)|
+---+---+
|
Primary Side IC (PWM Controller - Likely OB2263 or AP8012H)
|
+---+---+ +---------+
| Q1 (MOSFET - 4N60)|-----| T1 (Transformer) |
+---+---+ +----+----+
| |
R3 (Current Sense - 0.68 Ohm) |
| |
GND Secondary Winding
|
+---+---+
| D1 (Schottky Diode - SB3100)|
+---+---+
|
C3 (470uF/35V)
|
+---+---+
| R4 (Load Resistor - 1k)|
+---+---+
|
+---+---+
| U2 (Optocoupler - PC817)|
+---+---+
|
+---+---+
| U3 (Voltage Ref - TL431)|
+---+---+
|
R5 & R6 (Voltage Divider for 24V)
|
24V DC Output (+)
GND Secondary (-)
After analyzing three different PCB revisions (common in Chinese industrial supplies), here is the standardized schematic. Note that component labels (R1, C2, etc.) are generic, but values are specific to the 24V/1.1A output. Before diving into the schematic, we must identify