Do We Really Need The Exact Same Schematic Diagram?
Assuming if you come across a circuit that have few components burnt and you have no idea what the components are, the fastest solution is to look for the schematic diagram-am i right? The problem is sometimes we can’t get the exact schematic perhaps the equipment is still new in the market. The question is “Do we really need the exact same schematic diagram in order to find out the burnt components value?” The answer is not really. Why? because sometimes different brand of equipment could have the same design as yours so you could refer to that schematic instead of the exact schematic. In this post I’m assuming that you can’t get the original schematic diagram and trying to find an alternative way to find a solution to your problem.
Lets take this for example. Common power supply design utilize the UC3842 PWM IC and by comparing few of this design you will eventually roughly know what are the components in the power supply circuit. If the IC pin 1 connected to a 1 k ohm resistor you will notice that other model of equipment that use the same IC may have the same value of resistor (1k) connected to pin 1! I hope you get the idea.
Sometimes we just have to spend a little bit of time trying to find the “nearest” circuit design to your equipment model so that at least you will have some idea of what are the components that need to be used for replacement.