How to identify and solve a problem with the safety switch?

STEP 1  Locate the safety components 

There are more and more of these safety switches and sometimes they are so well hidden that it is very difficult to find them. In most cases, the switches are located on the base of the appliance and are operated by a plastic part on the jug or accessory. 

This example is an illustration of a plastic part on the jug of a blender that operates the switch on the base.
 

STEP 2 Check if all the safety components are fitted correctly

Check whether all safety components described in the user manual are fitted correctly to the appliance. These components may vary from one appliance to another.

This example shows you how to tell if the jug is mounted in the correct position on the base by using the two indicators on the unit. If the indicators are correctly aligned, the safety switch inside the device will turn on the device.

STEP 3 Check for deformations

The small plastic parts under the container, for example, can be easily broken or deformed by a fall, so that the safety switch cannot be operated. Broken plastic always has a somewhat irregular shape; sharp edges, sharp corners, roughness, etc. 
In this case, check whether it is possible to glue another piece of plastic in its place or to make a modification so that the safety switch is operated. 

STEP 4 Check for blocked switches

Some switches get stuck in a position where they cannot be operated due to oil, grease or other sticky substances. 
A possible solution is to take a small flat screwdriver and operate the switch manually. Try to move it until it works as before. The switches in question always have a spring that returns them to their original position. The part we are going to move must therefore move back and forth or up and down a little.

STEP 5 Check for residue on the contacts

In some cases, the switches are defective, broken or have been used for so long that they have accumulated a layer of carbon residue on their contacts. 
In this case, the appliance should be opened and checked with a tester (voltmeter). In some cases it is possible to clean the internal contacts of a switch and put it back in its place.

STEP 6 Replacement

If the above steps don’t work, the simplest solution is to replace the switch. 
If you want to find the exact model of your switch, you can check the switch’s number and use this in a search engine or you can visit a local electronics shop.
It is not always necessary to buy the original parts, similar models often exist and are much cheaper. Note that it is important that the NO and NC (Normally Open and Normally Closed) contacts are in the same position as the original part, otherwise the unit will not work.

Background information

General repair tips :

• Watch this video to understand even more about how safety switches work
• How to operate a switch tester / voltmeter
• How to clean the internal contacts of a switch
• Wiki Restarters : How to use a multimeter
• Wiki Restarters: The repair glossary
• Where to find spare parts ?

Caution

• Always unplug the device when working on it
• If you’re not sure how to proceed, contact a local repair café of a professional.