JYMC-220B-I (often searched as "jymc220bi") is a variable speed DC motor controller frequently used in Chinese mini-lathes and small machinery
If you are troubleshooting a specific issue, I can help you with: Identifying blown components like SCRs or MOVs. The exact fuse rating for your motor's horsepower. jymc220bi schematic 2021
And if you’re lucky enough to have the full internal schematic? Please share it – the community is still piecing it together one burned board at a time. JYMC-220B-I (often searched as "jymc220bi") is a variable
The PWM Control CircuitAt the heart of the schematic is a dedicated PWM controller chip (often a TL494 or similar SG series IC). This chip generates a high-frequency signal. By varying the "duty cycle" of this signal via the front-panel potentiometer, the user tells the board how much power to send to the motor. Battery management I1/I2: Inhibit circuit terminals to zero
What device is this board inside? (e.g., a treadmill, a motor controller, a printer?)
I1/I2: Inhibit circuit terminals to zero the armature voltage. 🎚️ Potentiometer Adjustments
Where ( R_top ) is between VOUT and FB, and ( R_bottom ) is FB to GND.
If you see 5.2V instead of 5.0V, replace the top resistor (typically 100k) with 91k.