DIAGNOSIS: Worn or dull blades. The stainless steel blades can become rounded and ineffective after prolonged use, especially if they've contacted hard items or the bottom of the jar.
FIX: Inspect the blades. Unplug the unit, unscrew the blade assembly from the jar, and look at the cutting edges. If they look rounded, nicked, or polished smooth, they need replacing. Order a replacement blade assembly for the BL1210BG model.
IF THAT DIDN'T WORK: The motor itself may be losing power. Test by blending a cup of water on high—it should create a strong vortex. If the water just sloshes weakly, the motor is failing and the base needs replacement.
HEADS UP: Blades are not sharpenable. Attempting to sharpen them will ruin the balance and can cause excessive vibration or breakage. Always replace the entire blade assembly unit.