The final report I mentioned about High voltage ceramic capacitor breakdown when beneath load. On this page I’ll chat about the high voltage resin coated ceramic disc capacitor. In computer system check, it really is frequent used in the monitor voltage (G2) line on the crt board. When it fails, it could possibly trigger erratic or intermittently raster dazzling and dim and occasionally no display screen.
Altering the flyback transformer display screen management is not going to remedy this issue. You may isolate the condition as whether if it induce by a defective fly again or G2 line at crt board. Remove the G2 wire from circuit and measure the screen voltage with a electronic multimeter- it ought to have a continuing voltage (will never fluctuate). If the voltage will not be steady suspect the fly again. If it Alright then trace the display screen voltage circuit. Ordinarily this circuit consist of only resistors and capacitors. Often a faulty crt socket may possibly trigger this sort of difficulty also!
Lots of periods a tech are not able to remedy this intermittent or no screen trouble is simply because their digital capacitance and ohmmeter calculated Ok about the capacitors. The capacitors during the display screen voltage line usually are rated of 102,103, and 472 1kv to 2kv. A ‘missed’ in checking this capacitors will caused the technician can not remedy the situation, unless of course he direct switch the capacitor. An intermittent capacitor can pull down the monitor voltage triggering the exhibit issue.
As stated previously, an ohmmeter with 12v output as well as a digital capacitance with 3v output are not able to precisely check out the capacitor that have the rating of 1-2 kilovolt!
In the event you provide the analog insulation tester or meter, the panel will present a short circuit when selected voltage are pump in to check the superior voltage capacitor. The voltages you can pick is depends on the brand or model you purchase. Some hold the range of 50v to 1000v and a few provide the range from 100v to 500v. It is actually optional irrespective of whether you ought to have a single. When you have 1 then it would be an additional edge to suit your needs. The opposite choice that you’ve will be to immediate replace the suspected capacitor. In my nation, you can obtain a new a person in less than US150.00 otherwise you might bid a employed unit from eBay.
As for me, examining the little blue resin coated ceramic disc capacitor which have the capacitor code of 104 50v, moreover using digital capacitance meter to check with the worth, i also use an analog meter set to occasions 10Kohm which have the output of 12v to check this sort of capacitor. Quite a few periods it can exposed the poor intermittent capacitor. You can be shocked to discover the capacitance meter checked Ok but present a shorted looking at when verify with analog multimeter.
On the market you can find specified brand of analog multimeter that have the choice of 100kohm. In the event you open up the cover, you can’t see the 9v battery in it, anything you see just the 2 pieces of 1.5v battery. Such a meter are unable to precisely detect the limited in the capacitor due to the fact the output voltage is simply 3volt!
For all those of you who involved in repairing observe, you may agree with me that examining the flyback interior capacitance- fairly normally you obtain the proper worth 2.7nf with digital capacitance meter but if you activate the keep track of, you will hear a ‘tick-tick’ seem from your flyback. This is due to the capacitor is breaking down when underneath load. For those who didn’t do nearly anything while using the flyback, little by little the internal capacitance will turn out to be shorted and you will have to refurbish the flyback.