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Check No Display - How to Repair Likom No High

by:Teeho     2020-07-01
Very well, no exhibit can be no significant voltage, failure in G1, G2 and heater circuit, faulty flyback transformer, failure in image tube and microprocessor or additional good reasons . In order to locate out the solution we have to swap on the Observe. On switching on the check, I could not hear any sound from the look out for but the energy led is on (green mild). Improbable experience any static at the glass of the photograph tube. This can be a signal of no large voltage indicator.Anyhow, I have to use my faithful Kaise SK9000 significant voltage probe to away if the substantial voltage current at the anode. Sometimes individuals really feel the static at the glass of CRT, doesn't necessarily signify the substantial voltage is not contemporary. It's only minimal in high voltage say could be ten to twelve kilovolts. Low higher voltage and no substantial voltage are absolutely two various signs. In the over scenario, my significant voltage probe registered zero volts! So it's confirmed no large voltage concern.There are several good reasons for no hollywood trouble. A missing B+ voltage, a faulty flyback transformer, no horizontal drive pulse from h/v oscillator ic, reduced or lacking provide voltage to horizontal driver transformer and for example could trigger no high voltage. Earlier point that I have checked was the flyback internal capacitor-the capacitance is in just the normal assortment which is 2.7 nanofarad. If the inner capacitor is shorted, it would cause no great voltage. The 2nd position that I have checked to be okay was the B+ voltage. It confirmed about 50 + volts and this imply there is supply coming into the B+ pin of flyback transformer. When checking the third level (the voltage at the main winding of horizontal flyback transformer), I identified that the rii zero volt and incredibly uncommon. The bottom push energy supply input has about 14 volts but immediately after the resistor it confirmed zero volts (by right it need to have about 12 volt-voltage drop soon bash resistor). When I placed my finger on the base push ability resistor just right after switching off the Keep an eye on, I could felt it was extremely very overheated. Now this is what we phone a clue. A good functioning base generate strength resistor won't end up with hot till it burns your finger! There ought to be a thing offers gone improper or shorted that produces the ability resistor turned incredibly very popular. From the outcome we get, turn out to be say that the horizontal push circuit is acquiring trouble so my focus is on this circuit.A shorted horizontal driver transformer main winding, horizontal driver transistor, components surrounding this circuit will result in the power resistor to flip extremely popular. The horizontal driver transformer key winding can be verify by applying a dick smith flyback tester even though the horizontal driver transistor and encompassing components can be test with an ordinary multimeter. The outcome, shockingly not just a single component in this circuit found in order to become faulty.Seeing that I can not find the defective parts, the best way to discover out at fault is to created my own schematic drawing base on this observe circuit (employing keep track of circuit idea to unravel issue).
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