Repairing Faulty Push Button in a PC Mouse

 24 July 2020

The left button of the mouse was not working. To fix the mouse, one would have to open up the mouse, cleaning the push button contact which might have bad electrical contact after years of usage. This video tells how to clean the contact.

To Reduce the Fan Noise in the PC Power Supply Unit

23 July 2020

Some power supply unit for the PCs have very noisy fans. The good one will come with a thermo controlled fan; the cheaper ones usually have this omitted especially when they are made for Bit-Coin mining machines. The solution is either to change the fan or have a fan speed controllers installed. This video describe how best to carry these works.
\
 

 Update:

The circuit in the video used IRF 634 which has a rated voltage of about 500V.  A cheaper euivalent is IRF 744 rated at 250 V.   The components are listed as shown

The veroboard layout of the component and its connection is as shown below

 

Do not Touch Any Power or Lamp Pole when Wondering in Flood Waters

20 July 2020

Floods are everywhere during this raining season.   They are in Japan,  India, China,  Indonesia,  Malaysia and many other parts of the ASIA.  In Japan, we have Typhoons.  In China and South East Asia,  we have the Monsoons and in India,  we have the heavy rain.   Some floods are not actually caused by heavy rain. Breakdowns in embankment of rivers and dams are often the cause in large area floods.

It is unfortunate to learn people died in floods. Some drowned; others electrocuted by high voltage electricity. Although lesser people died this year as compared to previous years. One thing we can help is by educating people to kick the habit of holding or touching the power or lamp poles in a flood.

This video was prepared using incidents happening in China recently.  It tried to explain why it is dangerous to hold on or touch any power or lamp poles when wondering in flood water.   Traffic poles are also dangerous in a flood.