if you use Nanjg 105C (D)
You can change the firmware of the microcontroller.
Use Pin6 for Turbo mode and Pin5 for Low Modes.
Use on pin5 one or more AMC7135 chips.
You can use this firmware
#define MAX_MODES 2
#ifdef REVERSE_SW //from Lo to Hi
#define SetMod0() Mod0075 //Pin5 PWM 8kHz
#define SetMod1() Mod0350 //Pin5
#define SetMod2() Mod2100 //Pin5+6
#define SetMod3() Mod2100
#define SetMod4() Mod2100 // Mode 5
#else //from Hi to Lo
#define SetMod0() Mod2100
#define SetMod1() Mod0350
#define SetMod2() Mod0075
#define SetMod3() Mod0075
#define SetMod4() Mod0075 // Mode 5
#endif