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Wrong Diagnosis In Electronic Repair

By on February 11, 2010

In electronic repair, if there is a wrong diagnosis in a circuit then the rest of troubleshooting time would be wasted. One has to be sharp and know what they are checking. Confirming the problem on a wrong section not only you can’t find the problem, your precious repair time will be lost. You have to be certain that the circuit you are checking indeed faulty otherwise you will not find out the fault because the actual fault lies in somewhere else.

In my yesterday post about the B+ coil, a small display can be caused by a failure in B+ circuit or even in the horizontal width circuit. If you did not check on the horizontal width circuit and just concentrate on the B+ circuit, I’m sure at the end of the day you will not find out the fault. In other word, before you start to troubleshoot any electronic equipment, analyze the schematic diagram and read as much as possible from forums or books that related to the equipment you want to repair. This will greatly reduce your troubleshooting time because now you know what circuit you should check.



  1. Trevor Jones

    February 11, 2010 at 4:01 pm

    Hi Jestine,

    PLEASE HELP!!!!!!!!!!!
    I have an ethernet switch (cisco 3550) with a faulty power supply. When you plug the power to the switch, it comes on gradually. At times, it takes up to ten minutes to come on, at times it does not come on at all. I suspect it comes on quicker if the weather is warm. Once it comes on it works properly. Please what do you think is the likely cause of this problem and how can it be fixed. New power supply is more expensive than the switch itself. Please help.

    Thanks a lot

  2. admin

    February 12, 2010 at 6:24 am

    Hi Trevor,

    Check all the electrolytic caps in the power section (primary and secondary section) with ESR meter. Please visit this website



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