Finding Good Test Points
Whatever electronic equipment that you are repairing one must know where are the good test points located. You can’t just simply use a voltmeter or Oscilloscope to poke around the board. You must know what you are doing so that once you have found the good test points, your troubleshooting and repairing time will be cut short. How are we going to find the good test points? By studying the block diagram and the schematic diagram of an equipment.
That means if you want to troubleshoot and repair Audio equipment, you have to get those diagrams and analyze it so that you will know where are the good test points. I suggest that the best is you jot down all the result of the good test points from a working unit and then compare it with the unit that have problem. At least with this way you could know whether the section you are troubleshooting is working or not.
If you expect a test point say at the output pin of a horizontal oscillator IC of a CRT Monitor to be a squarewave but you got a straight line. You will immediately know that the section have problem. The problem could be the bad IC itself or faulty corresponding components. Now i could not tell you all the good test points of electronic equipment because there are just too many electronic equipment in the market. You have to take initiative to find your own and this is for your own good too because once you have analyze the equipment that you are repairing you will be more familiar and when the same type of equipment have problem you will instantly know at where you should place your test probes instead of scratching your head of where to begin/start.
By the way, in certain electronic board you could see the word “TP” and this word means Test Point and the manufacturers purposely printed it out for repair technicians (in house technicians) to measure the section to see if the board that they had manufactured are good or bad.