The best cold ground to use is the turner ground (out part) or the CRT ground return. If you find still there is no voltage at the secondary output or the voltage is low, it is the time to substitute for the main B+ Load with a dummy load. You can make a dummy load by using a 40 watts bulb/250 vac, a bulb holder, crocodile clip and a wire(read and black) and connect them as shown on the picture below. Now identify the main supply to the fly back called the B+ and disconnect the supply just before the fly back B+ vcc pin. Don’t cut the circuit board to do this just lift up one side of a resistor( high wattage) in series with this B+ voltage or sometime they use a jumper wire just before the B+ vcc pin of the fly back and attach your dummy load between this point and the cold ground. If the bulb light steadily and you measure between 90 Volts dc to 140 dc depending on the size of the television then you can assume that the s.m.p.s is okay and the problem is on the secondary side.
Posted on: Thu, 01 Jan 2015 13:17:59 +0000
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