Computer Monitor display problems such as no display with high voltage symptom could be caused by many reasons. A defective picture tube, a faulty video preamplifier IC, a missing heater voltage, torn signal cable, negative G1 voltage became too high (-120 volt and above), CRT board problems, a missing or low G2 voltage and etc could cause no display but using present of hollywood.
In this particular article I'm in order to be show you ways to tackle a missing or low G2 voltage problem. First, you must confirm if there is high voltage present in the monitor. Can perform use a premier voltage probe to measure the anode voltage (24 KV) or can certainly try to listen to health benefits voltage sound produced (if you are experienced enough) once the monitor is turn on If worth voltage is there then your focus should be in the screen grid voltage (G2) rounds. If there isn't an high voltage, then I will explain it in another article.
How to be sure of if G2 voltage present at the pin for this CRT get on? By placing your positive probe (red probe) to the G2 point and negative probe to cold ground with power on, your meter should registered some reading. For your information, various kinds of of computer monitors, are usually place your multimeter towards the G2 point it would caused plenty of to closed down due to your caused of impedance loading of your meter. Assuming you measured a low G2 voltage say 20 volts dc (a good G2 voltage is anywhere between 250 - 300 + DC volt), the next thing you have to do is to isolate the problem to assess if is the G2 circuit that dragged down the voltage or the flyback transformer focus/screen voltage divider which in fact have gone bad.
Switch out of the monitor and desolder the G2 wire from the CRT landscape. Place your probe accordingly (red probe to G2 wire and black probe to cold ground) Now, put on the monitor and begin to see the meter readout. If the reading you obtain is still about 20 volts or better a little bit then suspect a defective flyback. Could certainly also are able to adjust the screen voltage associated with the flyback. If it already turned to maximum then flyback need to be altered. You can also have a cheaper way to resolve it. Make use of a monitor blur buster to in and defeat the original focus/screen cable and use the cable contrary to the monitor blur buster to do something as focus and G2. Thus, with method the newly tapped G2 voltage could be solder it back to its original location and definitely will get an exhibition when the monitor is switched on!
Now, let us say the readout from your meter shown 250 to 300+ volts dc as soon as the G2 wire voltage confirmed of routine? This is an enormously clear indication that there could be components that pulling down the G2 voltage to 20 vdc. From experienced, the resin coated type hollywood ceramic disc capacitor (usually in the 1-3 KV range) had caused a serious number of monitors became no display due for the capacitor pulling down the G2 voltage.
If you measure health benefits voltage capacitor with an electric capacitance meter or tester, chances are very high it reads okay (within the capacitance range). The truth is, may not rely on digital capacitance meter to use the capacitance value only, in fact this hollywood capacitor possess a high tendency to breakdown when under full load or operating voltage. The capacitor will only be accurately test along with a special meter like the Sencore LC103 capacitor analyzer.
The price this meter is very high, most likely I did I purchased a Kyoritsu insulation tester for checking great value voltage capacitor purposes. Just clip on your capacitor leads under test and press start, a good capacitor will demonstrate some charge and discharge reading nevertheless the spoilt you'll remained high and might not discharge.
Replacing simply the bad high voltage capacitor made the G2 voltage rise back to normalcy and solve the computer monitor display problems. I do hope you enjoy get ready for and please feel free to stop by website to learn electronic repair tips and secrets routine.
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