HCL4715W Rear projection CRT problem

If you have a picture, but only in green on a 3 crt projection TV, I would try turning up the drive for the red and blue guns. They have probably changed over time and red and blue have lost drive and need a boost. Green makes up 70 percent of the picture compared to red and blue so the drive would not have to drop much to lose red and green but still have green. Keep in mind that this does mean that the CRTs are dying and may not have too much time left.

To turn up the drives first remove the back cover on the bottom half of the machine. Be very careful as you will have to work on this unit live. Do not touch anything other than what I tell you and keep one hand in your pocket whenever possible.

First look at the space above the main circuit board. Somewhere across the beam supporting the CRTs you will see a square box with 6 controls (shafts). You can locate the box if you follow the wires from the flyback to the box. The flyback is located on the power board and produces the high voltage. It will have 4 large red rubber wires coming out of it. Three go to the focus divider block (the box in question) then they go on to the crts (red, green, blue).

Once you locate the focus divider look at it closely. The focus controls are on top and the drives are on the bottom. They should be marked red, green and blue. You want to turn up the red and blue. Tune a picture with as much black as possible. While watching it turn up the red until you see a red tint or streak then turn down until it just disappears. Do the same with the blue. You may want to touch up the green also for good color balance.

If the set is working OK and the CRTs have enough drive left, your picture should look normal.

Thanks for using FixYa.

hardrocko