About Electronic Board Marking
We all know that most of the electronic boards have board marking to represent the type of components in the circuit board. For example, a board marking of ZD represent zener diode, a board marking of R stand for resistor, a C stand for capacitor, Q stand for transistors and etc. Do you know that not all manufacturer follow the marking as i just mentioned above? In many Philip Monitor board, they used number like 2104, 3378, 8892 and etc as board marking and sometimes made us difficult as electronic repairer to identify certain components in those boards especially when you are looking from behind the board when doing the troubleshooting.
One more thing that i want to share is becareful when you want to remove the components from the electronic board. Some boards may have problem in marking the symbol. I came across a Monitor board that have the positive marking on the negative side and the negative marking on the positive side. If you have removed the particular cap and without noticing the reversed marking you may end up putting the electrolytic capacitor the other way round and may blow the capacitor once the power is turned “On”.
That means the positive lead is going to the cold ground and the negative lead to the positive line. And this marking was located on the secondary side of the power supply and carrying about 100 Volt! So be alert about the board marking whenever you want to remove any electronic components from it. I came across too a diode that have the symbol drawn reversed in the electronic board!