Electronic Repairing Article

The Four Senses

Sight, sound, smell and touch can solve a lot of electronic problems. They are the most important tools and can give you a strong clue as to the source of the problem. When the unit is opened, it must be inspected closely with the four senses; otherwise you may spend countless hours trying to find the culprit which is caused by a leaky electrolytic capacitor (oil leak) which you’ve missed out during troubleshooting.

Sight - You can see a cracked printed circuit board, a burnt resistor, blown

electrolytic capacitor, arcing from Flyback transformer, lightning damage, cracked diode, oil leak from capacitors, poor board connection, melted plastic of the Flyback transformer, cracked CRT neck and many more.

Sound - You can hear a tic-tic and high pitch sound from the Flyback

Transformer, arc over in the neck of CRT, capacitor bursting while the unit is operating, high voltage shutdown and arcing at the Flyback Transformer.

Smell - The oil from a leaky electrolytic capacitor can generate a powerful smell,

a burnt resistor also produces a smell and ozone smell from the Flyback Transformer.

Touch - You can use your finger to make a quick “touch test” of components in a

suspected faulty circuit. Overheated components in the printed circuit board are always a source of trouble. Always turn off the equipment before you begin to touch on the suspected components like IC’s, transistor and diode. Before you touch any components, be careful to ground yourself by touching the case of the equipment for a moment. If you don’t do this, you can accumulate a static charge, which can damage delicate CMOS ICs. Some components are hot even when they’re operating normally. If a transistor is attached to a large metal plate (a heat sink), you can expect the plate to be quite hot. A transistor with a smaller heat sink should be proportionally cooler.

Use of the sight, sound, smell and touch senses will reveal the untold story of the faulty circuit and may provide helpful clues.