Before you take a broken blender to a repair shop or buy a new one, check it for some common problems. Unplug the blender before working on it.
Jar leaks may develop in older blenders. In screw-off-bottom types, replace the rubber gasket if a check reveals wear or cracks. To cure leaks at the shaft, buy a new blade assembly.
If the blender operates slowly or erratically, sediment may be caked in the blade assembly. Take the jar off the base and hand-turn the blade. (Be careful not to cut yourself.) If turning is difficult, soak the assembly overnight in water and detergent. If turning is still hard, replace the assembly.
A chipped or broken coupling (the parts in the base and the jar assembly that unite the two) can cause erratic operation. Inspect the couplings and replace them if they are damaged.
Food or water splashing into the switch assembly of a push-button model can prevent operation at some speeds. Unplug the blender, carefully peel off the label surrounding the switch buttons, and remove the screws beneath. If there is a cap on the HI-LO switch, pull it off. On some blenders the switch assembly lifts out; with others you must turn the blender upside down and remove the hex nuts to separate the lower housing and the switch assembly. Use a penknife or a small, stiff toothbrush to scrape off caked food. Reinstall the switch.
Touch-switch models are sealed and so the switches are not likely to give trouble. But if you get the switch wet, you may damage it. Clean the touch panel only with a damp sponge.
If a blender won’t run in a working outlet, replace the plug. If it still won’t work, open the housing and check the cord with a continuity tester.