high voltage ceramic capacitor test should be done accurately an in a proper way. Adjusting the flyback transformer display control will not solve this dilemma. You may isolate the issue as whether if it trigger by a faulty fly straight back or G2 line in crt board. Eliminate the G2 wire from circuit and assess the display voltage using a digital multimeter- it ought to have a constant voltage (will not vary). If the voltage isn’t stable suspect back the fly. If it OK then trace the display voltage circuit. Usually this circuit include just resistors and capacitors. On occasion a faulty crt socket might cause this kind of problem also!
Many times a tech can’t address this irregular or no display problem is cause their electronic capacitance and ohmmeter quantified OK on the capacitors. The capacitors at the screen voltage line are generally rated of 102,103, and 472 1kv into 2kv. Even a ‘missed’ in assessing this capacitors will caused the technician can’t resolve the problem, unless he direct replace the capacitor. An irregular capacitor can pull down the screen voltage causing the display problem.
As stated before, an ohmmeter using 12v output along with a digital capacitance using 3v output are unable to correctly check the capacitor that have the score of 1-2 kilovolt!
If you have the analog insulation or tube, the panel will reveal a short circuit when specific voltage are pump into look at the high voltage capacitor. The voltages that you could choose is depends on the model or brand you buy. Some possess the assortment of 50v to 1000v and a few have the range from 100v to 500v. It’s optional whether you should have one. If you’ve got one then it would be an added benefit for you. The other option that you have would be to direct replace the supposed capacitor. In my country, you can find a brand new one in less than US150.00 or you can bidding a used device from eBay.
As for mepersonally, checking the tiny blue resin coated ceramic disc capacitor which have the capacitor code of 104 50v, besides utilizing digital capacitance meter to check for the worth, I also use a analog meter set to times 10Kohm who have the output of 12v to look at this kind of capacitor. Many times it will revealed the bad intermittent capacitor. You’ll be shocked to see that the capacitance meter assessed OK but reveal a shorted reading when assess with analog multimeter.
In the market there is certain brand of analog multimeter which have the range of 100kohm. If you open up the cover, you can’t see the 9v battery inside, what you see only the 2 bits of 1.5v battery. This sort of meter can not accurately detect the short in the capacitor cause the output voltage is just 3volt!
For all those who engaged in repairing monitor, you will agree with me that checking the flyback inner capacitance- quite often you have the ideal worth 2.7nf with digital capacitance meter however when you change on the screen, you will hear a ‘tick-tick’ noise from the flyback. This is cause the capacitor is breaking down when under load. If you didn’t do anything with the flyback, gradually the inner capacitance will get shorted and you will have to pay off the flyback.