Tip & How-To about Sony Grand WEGA KDF-42WE655 42" Rear Projection HDTV

How to adjust the screen drive on CRT projection TVs.

When your projection TV is getting darker and darker what do you do?

You need to turn up the screen drive on the CRTs.

As the CRTs age the elements get coated with oxide and do not put out the same amount of light. As the light output diminishes you turn up the setting on the menu but eventually there is no more adjustment.This is because the on screen menus are limited by the settings on the focus divider block.

Before turning the set off set the brightness and contrast to their center position in the on screen menu. Now turn the set off.

The next thing you need to do is unplug the set.

With the power removed remove the lower back cover. Usually this requires removing the screws marked with an arrow. The process should be obvious.

Once the back is removed locate the focus/divider block. It will be a small (4 x 4 inch) unit mounted to the frame (normally) and have wires coming from the high voltage section. It is almost always mounted on the right side of the unit on the frame holding the three CRTs.

The wires plugged into the unit will be large, soft rubber and red in color. There should be three wires. They should attach to the flyback which is the high voltage transformer. The flyback (high voltage transformer) will be mounted on the power/high voltage board and is almost always on the right side of the chassis.

The flyback generally is a squarish box near the rear of the unit and on the same board as the low voltage power supply. It may have a round cylinder in the middle, or not, but it will have a square laminated steel bar running through the middle of it. It will also be where the wires from the focus divider block, mentioned previously, terminate.

To set the drives you will need to power the unit up. Be very careful and try to keep one hand in your pocket at all times. There are lethal voltages inside this unit and if you do not feel confident working on it stop now.

When the unit has warmed up try to tune it to a black and white channel or a public information channel. If neither is available find a channel with alot of black and white in it. This is necessary to get the drives set properly.

Looking at the rear of the focus/divider block you should see 6 shafts. The top three are for focus. Do not touch them. The bottom three are the ones you want to change.

They should be left to right, red, green, blue guns. Turn each one in turn up until you see the color in the black of the picture then turn slightly down (until the color rastor disappears). Do each in turn until all are maximized.
They will be maximized and set correctly when the raster is just on the verge of being visible, but not visible.

The brightness should now be as good as it gets. You may need to turn up the screen menu drives for brightness or contrast to get the picture you were looking for.

Thanks for using FixYa and for the excellent rating.

hardrocko

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1 Answer

Picture is getting darker all the time.I updated the software.Still same problem, Adjusting personal prefrences doesnt seem to help.


Check the CRT fluid in the blue and green CRTs to be sure it is clear and not cloudy. A common problem. Since you mentioned the problem was gradual over time, I'm guessing it is the fluid. This would be more obvious if you were seeing like a frosted look to the picture or dark areas and bright areas, which are caused as the fluid clouds up. The picture tends to be more red as well.

Your alternative is to try adjusting the screen voltage of each bulb on the focus block of the tv. I think with an older Philips the screen/focus block is in the back of the tv. This is the little black module with six knobs coming out of it. Three knobs are for focus, and three are for CRT voltage.

Follow these steps:
Note: Be careful here, as hazardous voltages are very near by. Only use one hand inside the tv.
a) With tv turned on, go to a blank input screen
b) Very Slowly, turn the screen voltage up carefully for each CRT until you see arc lines of that color on the screen. Slowly back the voltage down until the arc line disappears. Do this for all three.
This should help with brightning up the picture if it is a voltage issue.

If the fluid is not the issue, then likely the flyback transformer is slowly failing and not providing enough voltage to the CRTs. Adjusting the screen voltage would help in this case.

Feb 20, 2011 | Philips 60PP9202 60" Rear Projection...

1 Answer

I have a light red hot spot just right and above center, any idea how to repair?


You have to take front projection screen off of tv. When you have taken screen off, turn on tv and observe light coming from the three crts. Look into the face of each crt and you will notice some contamination inside face of one of the crts. Most crts are sealed, so youll have to replace the burnt crt causing spot on picture.

Aug 19, 2010 | RCA P52926 52" Rear Projection Television

1 Answer

There is an image that is burned into the screen. How do I get rid of it?


Sorry to say if you have phosphor burn on one or more of the projection crts...........they need to be replaced and most likely not economical for a set of this age........sorry

Jun 06, 2010 | Sony KP-53HS10 TV

1 Answer

Picture turns on but is cloudy screen, it glows the colors but you can't make out the picture on the screen? Is it able to be fixed or worth fixing?


Yes,ur tv have crts coolants problems,it dead.Need it crts coolants replacement.Tries websites like Tvrepairworld.com,Tvrepairkits.com to buy a crt coolants replacement kit and follow the tutor dvd instructions to rejuvenate ur crts by replacing the crts coolants.

May 13, 2010 | Mitsubishi VS-50501 50" Rear Projection...

1 Answer

my Mitsubishi VS-50705 is dark on screen, do I need to replace the bulbs to fix it? where to buy the bulbs? Thanks


There are no bulbs in this set. Only 3 crts red,blue and green. crts are probably going out. repair expense will exceed value due to age.

Dec 06, 2009 | Mitsubishi VS-50705 50" Rear Projection...

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