Sunday, November 6, 2011

How to troubleshoot voltage issues?

You connect your over or refrigerator or tv power cord to electric power outlet.But this units will not work.You assume that problem is with tv or oven or with refrigerator.
But the actual issue is voltage at your place.
The voltage needs to be tested.
Before we can attempt to repair anything at all, there is one thing that one MUST do before anything else is done. Now that is, the making sure that the Power Supply,of the unit, no matter what it is, has the correct Voltages, coming into it, and more importantly, coming OUT of it. This is absolutely imperative, as, IF these Voltages are NOT correct then NOTHING will work, properly at all. So we must measure these voltages with a Volt Meter. or a Multimeter set to DC Volts. ( Always use a good quality meter, as if your meter is bad, so are your readings, and we can need to read to within, +/- 0.1 Volts). All Voltage measurements are made with reference to ground. Meaning we clip, our Black, Minus, Lead onto the Earth, or Chassis, or Negative (-) "Rail" of the Power Supply. Now with the Red lead, we can now, measure these Voltages. Now sometimes, the Voltage of each Output is annotated,or written, onto the PCB, that will indicate the Voltage of that output. However most usually they are NOT, so in this case we MUST have a manual to tell us. Now this manual is called a "Service Manual" or sometimes a "Repair Manual" This manual, is absolutely vital, so much so, that it can be near impossible, to do without it. To Order ANY "Bits" you need the parts, "Part Number" a Number that "Identifies" it to the Factory, so we/they know what it exactly is. Without that number you simply cannot get the correct parts. Also too, apart from having "Troubleshooting" step through's, it also has our Voltages. When we measure these Voltages they are 100% EXACT, so IF the Voltage you measure, except for a few rare exceptions, the "Rail" that is NOT at the correct voltage is the one, that the "Fault/Cause" is "ON". Therefore we can now work outwards from the Power Supply, looking for the cause of that problem. Now if the Voltage is Lower than specified, we are invariably looking for a "Short", something has "Faulted" and is "Dragging" the Power Rail down to earth. possibly a Capacitor, or Diode, or an IC. Now if the "Rail" is "Higher" than the specified Voltage then the fault we are looking for is usually some sort of "Open Circuit" possibly a Diode, or Resistor, that has changed it's "Value", due to heat or stress. Now knowing this, and knowing that, the Power Supply is the FIRST & ONLY place to start you troubleshooting and repair from. You now have a MUCH better chance of a "Fix". 


This above mentioned details will help you to troubleshoot voltage issues.




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