Question about Samsung HCL4715W 47" Rear Projection Television

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HCL4715W Rear projection CRT problem

My Red CRT is dim, and the dials directly on the CRT boards for all three CRTs (red, green, and blue) have no response. Just changed SUB PCB because of convergence problem. Convergence fixed, but now color is bad due to red being dim.

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Re: HCL4715W Rear projection CRT problem

Your screen and focus controls need adjustment to acheive a good grey scale picture the adjustment are not on the crt neck boards.(focus block)

Posted on Sep 04, 2007

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Why does the tv look have a red tint all the time

The CRT coolant is needing replacement in the blue and green CRTs which make the red dominate. You can see the coolant is bad by looking in all three lenses you will see that the red is clear and bright where as the blue and green will be hard to see through which makes the colors dim. Replace the coolant should solve the issue. You can get the Phillips CRT coolant kit from which contains the coolant for all three CRTs and the CD with instructions.

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What to do when you only have Green on a CRT Projection TV.

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.


on Sep 22, 2010 | Toshiba 50H81 50" Rear Projection...

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When tv is turned on screen is red only why???

the CRT coolant can get contaminates which dim the blue and green CRTs so the red appears real dominate. Looking into the lenses of the three CRTs with a flashlight will verify if the coolants the issue .

Sep 12, 2010 | Philips Projection Televisions

3 Answers

Magnaovox rear projection tv has too much red in the picture and it is blurry

Sounds like a coolant issue with the CRTs. Look into the lens of the green and blue CRTs and you should see what looks like bacteria if the coolant nees replacement. Usually the green and blue get contaminated which dims them and makes the red become dominate and the picture will get dim and out of focus.

Jan 22, 2010 | Philips Magnavox 51MP392H Rear Projection...

1 Answer

Blue CRT issues?

Yes the puddle is related to the Blue CRT coolant leaking. You are most likely going to need a new Blue CRT drive circuit board and quite possibly a new Blue CRT if the CRT got too hot from not haveing a sufficent supply of coolant. You can get replacement CRT drives and CRts at the following link.

Jan 15, 2009 | Samsung HCL4715W 47" Rear Projection...

1 Answer

What is a red crt?

There are three 'picture tubes' (CRTs) used in that kind of set rather than one with three colors as with the older TVs; red, blue and green. They operate at very high levels of light emissions in order to illuminate the large screen of the rear-projection set.
More here:
Rear projection TVs 

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1 Answer

Samsung HCL4715W...

look for a blown fuse around the flyback

Dec 15, 2007 | Samsung HCL4715W 47" Rear Projection...

1 Answer

Red CRT is dim....

Yes I did. You will need to get a service manual for this TV set to trace the voltage coming from the sweep power supply. If this is a problem that is new after you replaced the convergenbce4 board, you for sure have a broken wire or connection somewhere in the set. Have seen this happen may many times after a novice repairs a TV set. Good Luck

Sep 06, 2007 | Samsung HCL4715W 47" Rear Projection...

1 Answer

Internal Screen Adjustments No Response

thr focus block assy.has the screen and focus controls on it it about 3"x3" in size has red wires attached to it and one feeding form the flyback transformer to it.

Aug 29, 2007 | Samsung HCL4715W 47" Rear Projection...

2 Answers

HCL4715W Rear projection "Red" color is dim

screen adjustment,remove front bottom cove and find the focus block the screens are also on the same block,if your not sure don't try.

Aug 28, 2007 | Samsung HCL4715W 47" Rear Projection...

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