How To Repair Electronic Equipment with Button Switches

3 April 2014

Introduction

These “critters”,  button switches,  are often used in our electronic equipment whenever there is a button designed to be pressed either to reset a program or to do the programming.

These buttons are cheap but they are often not lasting especially those in the cheaper electronics equipment such as door bells or some remote controls. One would need to press the buttons extra hard in order to sound the door bell or to activate the remote control.

Why?

There are 2 reasons:

1. The current that passes through the buttons is not enough to overcome the “dirt” building up at the contacting point. When the contacts of the button are making or breaking, there will be “sparks” no matter how small, these “sparks” will usually “blow” the dirt building up in the contacts.   If the current is too small,  the sparks created will not be able to "blow" off the "dirt".

2. The current that passes through the button is too strong, hence,  causing sparks to “eat away" the metal of the contact surface and therefore, building carbon resistance enough to prevent the passage of the current.

How to Repair?

First, remove the buttons carefully,  making sure the circuit board is not damaged, then

1. Replace the buttons

This is the best option.

2. Open up the button and then clean the contact. 

This will require some skills to break open the cover and then reseal it after cleaning. Not often successful

3. Pass a small current through the button using a torchlight battery with as many pulsation clicks as possible  (i.e to click the button switch as quickly as possible, say 20 clicks) until the ohms meter measurement across the button switch shows consistent low resistance readings. Do not leave the button switch  close for too long as this will short-circuit the battery.

Method 3 may not necessary work when the contacts of the buttons are completely charred and worn. In that case, the only workable solution is to replace the button switch.   However,  method 3 may be a quick method as it could be done "in circuit"  when one can isolate the switch from the circuit. In the case that one torchlight battery cannot do the job and the button switch came back with the same problem,  try maximum 2 nos of batteries working in series.