The is a widely used DC motor speed control board. It is most famously known for serving as the primary control board (often used interchangeably with units like the SCR340 or JSCR240) for standard hobbyist and compact machinery, such as the popular SIEG CJ0618 7x12 or 7x14 mini metal lathes. Operating as a Silicon Controlled Rectifier (SCR) phase-control circuit, it converts alternating current (AC) from the wall into a variable, rectified direct current (DC).
In the absence of a digital copy, consider creating a partial for your specific board.
Disconnect power. Set your DMM to continuity/diode test mode. Measure across the drain and source pins of the power transistors. A reading of
Connects directly to the DC brush motor. jymc220bi schematic full
Main single-phase alternating current power line connection. On the 220B-I variant, this receives 230V. On the 220B-II variant, it connects to a 115V line via the machine’s master On/Off latching safety switch (such as the standard KJD17B Electromagnetic Switch ).
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Always disconnect the machine from the wall. Inspect the board for bulging or leaking electrolytic capacitors, charred resistors, or cracked traces on the underside of the PCB. Look closely at the legs of the power transistors on the heatsink for signs of melting. Step 2: Check the Power Semis The is a widely used DC motor speed control board
1PC DC speed control board JYMC-220B-II 12A 115V lathe control board Go to product viewer dialog for this item. Input Voltage 230VAC ±10% (50/60 Hz) Input Voltage 115VAC ±10% (50/60 Hz) Output Voltage 0–180 VDC Output Voltage 0–110 VDC / 0–180 VDC Rated Current 12A DC Continuous Rated Current 12A DC Continuous Drive Technology SCR Thyrister Phase Control Drive Technology SCR Thyrister Phase Control Compatible Motors 450W – 1100W Brushed DC Compatible Motors 450W – 1100W Brushed DC The Full Architectural Schematic Breakdown
The JYMC-220B-II is a printed circuit board (PCB) designed for variable speed control of a DC motor. It is not a stand-alone consumer product but rather a critical internal component within larger machinery.
These components are physically bolted to a large aluminum heatsink to dissipate the massive amounts of heat generated during low-speed, high-torque operation. In the absence of a digital copy, consider
Ensure the heat sink has adequate airflow; enlarging the heat sink can help if running high-horsepower motors.
The output stage acts as the heavy lifter. In older or simpler variations of the JYMC boards, high-current are used in a phase-angle control setup. In modern variants, high-speed MOSFETs or IGBTs handle the PWM switching.
The is a highly popular PWM (Pulse Width Modulation) speed controller widely used in mini lathes and milling machines, such as those manufactured by Sieg (X2, C2, C3), Grizzly, and Harbor Freight. Understanding the JYMC220BI schematic full layout is essential for machinists, DIY electronics enthusiasts, and repair technicians looking to troubleshoot, repair, or modify their benchtop machinery.
The JYMC220BI is a versatile component with a wide range of applications, including:
: 230V AC passes through an onboard protection fuse and a Metal Oxide Varistor (MOV) network. The MOV shunts voltage spikes to shield the delicate downstream silicon components.