Between all the electronic repair service article content that I have sent to you, this technique is look at a minimal bit hazardous if you do not know what you are accomplishing. For these who are new in this subject I propose that you only apply it with the aid of a senior tech. Research this report carefully and the important precautions that a single need to acquire prior to starting to use this trick. Nonetheless, if you consider that you have the bravery to try out, then go forward to accomplish the take a look at.
A 15″ Philips 105s7 Observe arrived in with the complaint of show blur. Generally the first issue that a technician will do is to tune the concentrate adjustment knob at the flyback transformer to get a sharp image back. On the other hand, in this situation while tuning the emphasis alternatively of anticipating a sharp image, you get a brighter raster (white track record) with flyback retrace traces throughout the display screen. Normally when you turn the concentrate knob, only the character get sharper without having influencing the raster and this is also legitimate when you tune the display (G2) knob adjustment, only the raster will have outcome but not the focus.
Because modifying the concentrate management has impact on the raster, this evidently tells us that there ought to be a thing that had gone mistaken in the keep track of. With this problem, I could only feel of 3 areas that I have to check i.e a shorted flyback transformer divider community, a defective CRT socket and a defective photo tube. In purchase to affirm if the flyback transformer divider is shorted or not is incredibly very simple. Just use a Monitor blur buster (MBB) and defeat the original concentration and screen cable by connecting the concentration and monitor cable from the Monitor blur buster. Now tune the aim or display regulate at the MBB to see if the photograph receives sharp or not. If you get a sharp picture we can conclude that is the flyback transformer divider community that is defective and if the image stills blur then it can only be the CRT socket faults or a negative image tube.
In order to confirm if the CRT socket is the induce of the issue, one just has to exchange with one more functioning CRT socket to see if there is any advancement in the image. If it still blur then I believe you are now certain as which a single is the accurate bring about of the photo blur problem-it is the CRT or photograph tube! If it is image tube challenge, then you may well question, can it be restore or not considering the fact that a photograph tube is a vacuum tube that are not able to be disassemble? Sure, it can be done but with some safeguards that you want to choose.
To repair service this sort of difficulty, a single should 1st understand how a picture tube was built in particular the electron gun. I would not go far too particulars about electron gun but I will enable you know that the concentrate and the display screen G2 plate is the closest and if there are any dirt’s or particles that had happened to be between the two plates, then it would absolutely affect the exhibit (photograph will become blur, dim or as well brilliant with flyback traces).
After you have certain that the lead to of the difficulty is image tube, now take away the CRT board from the neck of the photograph tube and identify the pins of display (G2) and concentration. If you search at the photo, most of the CRT pin outs is virtually the similar except to some Sony Trinitron tubes. Link an alligator clip amongst the target pin and cold floor and the G2 pin to the shaft of the flat variety screw driver. The motive for connecting the alligator clips in this sort of a way so that the created Watch large voltage (about 24 kvdc) can be use to spark off the inside shorts in the electron gun involving the focus and G2 plate.
Right before you swap on the Keep track of, be sure to make sure you disconnect or unplug the VGA sign cable from the CPU in any other case when the discharge commences it could wipe out the CPU VGA card. Not only that, remember to check out any bordering in the Observe as no extra wires or cables touches the electric power part, if not it may blow the ability provide. As described in the earlier mentioned to start with paragraph that this process actually want you to be exceptionally careful and warn so that absolutely nothing would happen when you start off to discharge the higher voltage as a result of the anode cap.
If you are completely ready now, keep the cope with of the screw driver (try to remember, the cope with have to be thick otherwise certain of the superior voltage might jump across and discharge as a result of your hand) with your left hand and electric power “ON” the Monitor. When the substantial voltage have current (with the speeding audio you’ve got listened to), now swap off the Observe by urgent the entrance panel on/off button, you then swiftly poke in the screw driver shaft to the anode in advance of the higher voltage getting discharge by the bleeder resistor in the flyback transformer. In other phrases, we want to benefit from that brief minute of the large voltage to spark off the shorts in the electron gun prior to the significant voltage currently being thoroughly discharged.
Commonly you will listen to a “pop” sound when the higher voltage arc by the screw driver shaft at the anode cap. Repeating this for couple times and the shorts definetely will go away. Link the CRT board again and check the Watch to see if the dilemma has been solved or not. Assuming the Monitor even now blur soon after few of the discharged, you can usually reverse the alligator clips where now you are connecting the G2 pin to chilly floor and working with the emphasis position to poke through the anode cap. This will normally obvious the shorts away
Bear in mind, the blur issue in this short article is entirely distinctive from the blur trouble (blooming) prompted by a defective flyback transformer divider community the place you need to have a Check blur buster to fix it. Using the technique above I’ve solved plenty of this Keep track of blur difficulty whether it is a 14″ or 21″ Check!