The past post I mentioned about electrolytic gold capacitors breakdown. In this article I’ll talk in regards to the high-voltage resin coated ceramic disc capacitor.it’s regular used while in the display voltage (G2) line in the crt board. If it fails, it can cause unpredictable or occasionally raster glowing and subdued and occasionally no display.
Correcting the flyback transformer screen control don’t solve this dilemma. The problem can be isolated by you as whether supposing it trigger with a flawed fly-back or G2 line at crt table. Eliminate the wire from circuit and assess the screen voltage with an electronic multi-meter- it ought to possess a persistent voltage (will not change). If the current is not steady imagine the fly-back. Whether or not it OK subsequently outline the screen current circuit. Typically this signal include simply resistors and gold capacitors. A flawed crt outlet might cause this type of difficulty also sometimes!
Often times a technology can’t resolve this occasional or no display issue is basically because their electronic capacitance and ohmmeter measured OK on the capacitors. The capacitors within the display voltage point usually are graded of 102,103, and 472 1kv to 2kv. A ‘missed’ in checking this capacitors may caused the tech may not solve the difficulty, unless he direct substitute the capacitor. An occasional capacitor may pull down the screen voltage causing the display issue.
As mentioned before, an ohmmeter with 12v output signal and a digital capacitance with 3v output signal are unable to correctly assess the capacitor that possess the rating of 1-2 kilovolt!
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The panel will show a short circuit when particular voltage are pump in to check the high voltage capacitor, if you have the analog insulating material examiner or meter. The voltages that you can choose is depends on the brand or model you buy. Some have the range of 50v to 1000v and some have the range from 100v to 500v. It is discretionary whether you should have one. It would be an additional advantage for you if you have one then. The other choice that you have is to direct replace the suspected capacitor.
As for me, assessing the small blue resin coated ceramic disk capacitor that have the capacitor code of 104 50v, besides using digital capacitance meter to assess for the value, I also use an analog meter set to times 10Kohm that have the output of 12v to assess this type of capacitor. Many times it will revealed the poor spotty capacitor. When check with analog multimeter you will be shocked to see the capacitance meter checked OK but show a reading.
In the market there is particular brand of analog multimeter that have the range of 100kohm. This sort of meter can not correctly discover the short in the capacitor because the output voltage is only 3volt!
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