These 17 "CRT Relisys OEM Monitor came (to the complaint of dark display screen can not be seen again).) Although on the front of the On Screen Display (OSD, you have to adapt, to show still does not return the maximum grid and the whole display appeared quite dark. Usually when we see this kind of dim display problem, we go straight to the flyback transformer and adjust the screen (G2) voltage regulation to increase the tension on the tube so that theDisplay is bright again.
Somehow, developed in certain CRT monitor, there is no screen (G2) control (Button) for you to adapt. It contains only two buttons for you to) the focus (F1 and F2 buttons. Since we can unfortunately no control G2 is available on the flyback transformer, one would always preset brightness control for internal search, but unfortunately this is not a model. It is only the B + control and preset voltage. The high voltage preset has been glued withSilicon, and we simply can not agree that target otherwise the screen will temporarily go into shutdown mode. The only preset that is for you to adjust the B + control. Yes it is true that sometimes in certain monitor you can tune the B + control preset in order to increase the brightness, but it is not recommended, as is the increase of the B + voltage, the load on the horizontal output transistor (HOT) to increase. The HOT can not last long and it sometimes in a few hours blow.
In thisMonitor had, tried to adjust the B + preset to see if the brightness could be displayed or not, but the result left the show to go on and still dark. If I am to the tune of the B + control continues, I fear, the HOT may blow in a very short time! This is just an experiment, only the fact that it can not agree to control the B +, without a good reason.
After the monitor was used for several years, the CRT cathode can) (emissions become weak and this causes the display fades. Tothe display will be brighter again, you can use the heater voltage of 6.3 volts to about 8 to 9 volts. Or you can change the G2 circuit to the tuning voltage without any increase in B + or high-voltage preset in the monitor. In this article I touch only on the change in the G2 circuit.
Since the flyback transformer does not have the control of G2, we can not search by the fly-back track for the G2 wire. In fact, we can back out of the CRT traces on the printed circuit board to see where theG2 wire came from. Yes, it came out of the motherboard and not from the flyback transformer. Reversing the motherboard one can easily see the small G2 circuit, a diode, high voltage capacitor, and includes some very high ohm resistor.
This is working as the G2 circuit. The high pulse AC supply came from one of the flyback transformer secondary PIN and go through an ultra fast recovery diode. The function of the diode is the high ac voltage pulse in and convert the highUsing capacitor (102 2KV resin-ceramic types) filter in front of the high-frequency waves, and then the voltage flowing through the resistors and the resistors determines (set) the output voltage. If you understand how this circuit work, you can easily change the circuit or change the value of the resistors to increase the G2 voltage.
From the picture you could see clearly that resulted by removing the jumper and has a 4.4 mega-ohms (2.2M in series with another 2,2 M to the conclusionof 4.4 M ohms) I could slightly increase the G2 voltage. You may ask: "How do you get the 4.4 M value?" In fact, I've tried a few high values from 100 K ohm resistor and then 1 then M 2.2 M, before I conclude that 4.4 m) have the best Ohms display (brightness. If the jumper (link) to remove the display is too bright and not good for the user.
In some designs of G2 can monitor voltage in the highest value, and if that happens, no matter what resistance value, the change orChange the circuit, the G2 output voltage is still the same, because the G2 voltage is already the maximum. You can only at the lower end of the G2 voltage, and there is no possibility to increase the voltage to G2! If this has happened, then you need to increase the filament voltage in order to change the brightness.
In the final act in an electronic circuit, if you can really know how to work a certain distance, you actually do some changes to the electronic devices to work again. If the electronicEquipment no longer considered to be repaired, there is no harm in trying out any modification method that you can think is the best make the electronic devices to work again. To do this, you need to equip first you have a basic understanding of electronics theory have. For your information, the problem described above is a common mistake, and I have solved a lot of it and some nice income from an easy 10 minutes work. Have a great day my friend!
ไม่มีความคิดเห็น:
แสดงความคิดเห็น