Testing Resistor

Resistors vary from type. But today i would like to focus on fixed resistors like  carbon resistor, carbon film resistor, metal-film resistor. As a technician we usually test resistors by its resistance if it is open, decreased its value or increased its value because it has tolerance. In E-24 Series Chart Color Code there are four colors that are usually put as tolerance which is brown (+/- 1% which means that a resistor can increased  and decreased only up to the said percentage beyond that you must replaced your resistor in that circuits.) Red tolerance equals to (+/- 2%). Gold tolerance equals to(+/- 5%). Silver tolerance equals to (+/- 10%). But normally majority of the tolerance you will see in a resistors in the circuit were Gold and Silver. You can measure the value of resistor by analog multimeter or digital multimeter which is easy to used and easy to read the value of resistor. We usually checked resistors one way test and we assured if we got the value it is okay. But one time there is a tv that brought to me by a customer. It has a raster but when you put an antenna and plug it in the back it cannot received the channel. Because the raster  in that tv  when i saw it in my perception this is not the normal raster that i usually saw in a good tv. I looked on the mainboard of the tv and someone has work on it already because of fresh solder and the previous technician said to the owner they must change the picture tube that's what the owner said to me. So i looked on the CRT circuit of that tv and i saw a two watts resistor which is unusual in visual because it has a little crack on the body. When i test it with my analog meter on usual way it is ok but i reversed my probe the pointer of the meter move backward instead of forward so i was amazed because this is my first time to encounter such trouble to resistor so i changed it and the tv works perfectly. So even if you changed the picture tube it will not work because there is a component that breakdown. The tv is a promac. If you will encounter such problem look on that section of the CRT circuit of that tv.

carbon resistor 

carbon film resistor

metal film resistor.