The last post I mentioned about aluminum electrolytic capacitors dysfunction when under load. In this post I ‘ll discuss the high-voltage resin coated ceramic disk capacitor. In pc monitor, it’s regular used in the display voltage (G2) line at the crt board. It can trigger unpredictable or intermittently raster subdued and glowing, when it neglects and occasionally no screen.
Fixing the flyback transformer display control is not going to solve this issue. You’ll be able to isolate the trouble as whether if it trigger by a flawed fly rear or
G2 line at crt board. Remove the G2 wire from circuit and calculate the display voltage with an electronic multimeter- it should have a steady voltage (won’t change). If the electrical force isn’t constant suppose the fly-back. If it okay subsequently outline the display voltage circuit. Typically this circuit include capacitors and only resistors. Occasionally a flawed crt outlet might cause such a trouble additionally!
Many instances a technology can not fix this spotty or no screen trouble is because ohm meter and their electronic capacitance quantified OKLA. on the capacitors. The capacitors in the display voltage line usually are rated of kv to 2, and 472 1 102,103 kv. A ‘missed’ in assessing this capacitors will triggered the tech can not fix the trouble, unless he direct change the capacitor. An occasional capacitor can pull-down the screen voltage creating the show trouble.
As mentioned previously, an ohm meter with an electronic capacitance with 3v output signal and 12v output signal are incapable to precisely assess the capacitor that have the evaluation of 1-2 kilovolt!
The panel will reveal a short-circuit when specific voltage are pump into assess the high-voltage capacitor, if you’ve the analog insulating material tester or meter. The voltages you could pick is depends on the tradename or version you purchase. Some have the variety of 50v to 1000v and some have the variety from 100v to 500v. It’s elective whether you should have one. If you’ve one then it’d be an extra edge for you. Another choice which you have will be to direct change the suspected capacitor. In my own state, you’ll be able to get a fresh one in less than US150.00 or you might offer an utilized unit from ebay.com.
As for me, assessing the little blue resin-coated ceramic cd capacitor that have the capacitor code of 104 50v, besides utilizing digital capacitance meter to assess for the worth, I additionally use an analog meter place to instances 10Kohm that have the output signal of 12v to assess such a capacitor. Many instances it’ll shown the terrible spotty capacitor. When test with analog multi meter you’ll be shocked to see the capacitance meter assessed OK but reveal a shorted studying.
In the marketplace there’s specific brand of analog multi meter that have the variety of 100kohm. If you open the protect, you can not see the 9v battery in it, what you see just the 2 bits of 1.5v battery. Such a meter can not precisely find the brief in the capacitor because the output signal voltage is simply 3volt!
For those who entailed in mending screen, you may agree with me that assessing the fly-back internal capacitance- rather regularly you get the correct value 2.7nf with electronic capacitance meter but when you turn on the screen, you’ll hear a ‘tick-tick’ sound from the fly-back. This is only because the capacitor is deteriorating when under load. Slowly the internal capacitance can be shorted, if you didn’t do something with the fly-back and you may have to refurbish the fly-back.Click here to read more infomation about aluminum electrolytic capacitors.