This post explains for the controller.
The Part Number is GS069.
The function of this semiconductor is DC Rotational Velocity Controller.
The package is SO-8 Pin Type.
Preview images :
The GS069 DC rotational velocity controller is an application-specific CMOS IC for electrical tools. It features wide power supply voltage range, low power dissipation and high interference immunity.
It controls the rotational speed of electrical tools by changin the output of the VMOS transistor through an external resistor network.
1. Wide power supply voltage range
2. Low power dissipation
3. High interference immunity
4. Wide output range
5. Small frequency variation[…]
1. Electrical tool switches