It is common to LCD television we for correction. Symptom of the problem is almost always turns on TV for a short time, “digital TV” appears in the lower right and then the TV goes off and returns to standby mode.
This type of error is almost always due to power failure or circuit inverter in most LCD TVs. Normally, I start by measuring the output voltages from the power source during the time that is to see if any tolerance or lack of starting the inverter circuit, control circuit ring welding cracks and check the capacitors on the supply side of raised ESR and secondary power filter control pico fuses and transformers is the inverter circuit, etc.. but this model I know that one of the transformers high voltage inverter circuit is often a secondary winding develops open, is usually a place of high-voltage transformer T1100.
The first thing I do with this model is check all the secondary windings to see if any have opened by measuring there resistance, an open winding will have an infinite resistance or if you are using a DMM you will get an O.L. (Over Limit or Open Loop) reading. Each one of the HV transformers in this model TV has 2 secondary windings.
While the measuring of resistance, I find that none of the secondary windings were open, but what I noticed is that one of the secondary windings have a resistance much lower, so that all other I measured. All secondary windings have a resistance of between 522 and 527 ohm secondary winding and the suspect had a resistance of 495.4 ohms, about 30 ohms is less than the rest. It was a very good indication that the secondary winding was cut short. This is great on the test of HV transformers in most LCD TVs, to compare the test results of a transformer to another, usually a single high voltage transformers will go wrong, and it will be easy to identify when tested and compared against the other.
Upon closer inspection of the transformer with the shorted secondary winding the burned area of the secondary winding was noted as well, confirming without a doubt that the transformer was faulty and sure enough it was T1100, the transformer that we normally replace in this model but always for an open secondary winding but this time obviously the winding was shorted. Most likely what typically happens is the secondary coil shorts and then excess current is drawn as the resistance of the coil drops which in turn causes the coil to heat up and burn causing it to go open, but in this case the coil shorted and the TV shutdown before it had a chance to open.
After the HV transformer was replaced with a new one, part number LTZ2PC0MS008(substitute for 3PC0XB001) the TV turned on and functioned properly once again.
The LTZ2PC0MS008 can be found at Electronica USA along with many other electronics components.
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