Tip & How-To about Televison & Video

The reason their is no blue color in you projection screen picture.

Over time the Blue CRT in your projection screen produces a thin layer of fungal growth over the top of the tube. This attracts dust particles and as they collect they blocks the light from getting to your screen. This seems to happen with only blue CRT's. To clean it remove lenz and use a damp terry cloth with a water and bleach solution. Wipe the convex part of the tube untill it is free of all dirt and fungi. Replace lenz and get ready to enjoy a very sharp picture.

Posted by on

Televison & Video Logo

Related Topics:

Related Questions:

1 Answer

my mitsubishi vs 6047 has been in unheated storage for about 4 years. now picture is very blury. when words are on screen large letters are legible with small white horizontal lines dancing side to side. sound is fine. same result receiving from antenna or from dvd player.


Does the picture look like this?

dcramer531_118.jpg
If so I believe your CRT liquid coolant has gone bad and needs replaced.
How to diagnose bad CRT Coolant:

Note: This problem will only affect the GREEN and BLUE picture tubes. The RED CRT is never affected, because the wavelength of the red light does not promote this algae growth
General Symptoms: Washed out, blurry picture, red portions mostly OK, GREEN images have halos, BLUE portions of images may have halos or be missing entirely.Turn the color level control all of the way down and remove the screen and/or the cabinet that contains the mirror. (different for different models) Do not turn the set off or the color level control will reset to preset levels. Look directly into the picture tube lens while the set is on. First look at the RED CRT. Observe the scan lines in the picture. These same lines should also be present in the green and blue picture tubes.
After looking at the RED CRT for comparison, look into the GREEN or BLUE CRTs. If it is contaminated, it will look like there is a layer of film that you have to look thru to see the picture. There may also be swirls and other various contaminates forming. If it is not as clear and sharp as the RED CRT, it is contaminated, and you should change the coolant fluid. IF you wish to tackle this I will supply more information and instructions. This task is medium to hard for non trained people.
Let me know if you wish to get the instructions on changing the fluid.



Jun 09, 2011 | Mitsubishi VS-6047 60" Rear Projection...

1 Answer

our samsung projection tv has occasional blue marks on the screen, which is recent. Is this a problem with the tv? or something to do with Directv?


I suspect that it may be just dust particles on the projection tube lenses.
Take the front off and clean the dust off the lenses.
I hope this has been helpful

Oct 20, 2010 | Samsung Televison & Video

1 Answer

hi, we have a dim darkish orange screen that is pretty dark... we bought this tv from an auction (at which they stated it all worked properly, which i was skeptical but dont think that this is "working properly") thanks for any help you can provide


Over time your blue CRT in the back of your set develops a fungal growth that covers up the glass and prevents light from shining through clean this off with a cloth dampend with waterd down bleach. While you're in the back of the set clean all 3 of the tubes of with this solution. After that wipe the back of the screen off with a dry cloth. Wipe the delfection screen of as well this is the screen that is diagonal to your front screen it actually deflects light to the back of the screen you watch. These can become very dusty over time and block light. This should fix your problem. If it doesn't the fluid in your 3 cathode ray tubes is cloudy and will have to be changed by a tech.

Aug 02, 2010 | Samsung HC-R4755W 47" HDTV

1 Answer

Blue washes out whole picture


Hello....I have been working on these (and it's Samsung counterpart - HCM4215) for about as long as they have been on the market. I have ran into this problem on the blue and green CRT many times. Most of the time it is a bacterial growth in the glycol coolant. This model is notorious for leaky tubes (they have the worst rubber seals ever invented for a CRT), and air bubbles trapped within the tubes which allows for an algee-like growth in the fluid compartment between the screen and the primary lens. If this is the case, you will have to remove and drain the CRT, completely clean the assembly with denatured alcohol, and refill it with glycol coolant. If you have rebuilt these things before, this is probably no new task for you!!

 

I have also ran into bad components on the CRT driver boards with this model. They have always been the variable resistor for the drive (VR501 1Mohm) or one of the three 1/2W resistors right next to it associated with screen circuit. If you don't see retrace lines, then I would bet on the algee!!! Hope this helps out.....please let me know how you make out on it.

 

jdavid_3343@yahoo.com

 

 

 

Oct 09, 2007 | Akai PT4298HD Rear Projection Television

2 Answers

dim picture


If decide to do yourself, ya only have to do the green and blue ones, the red light spectrum won't allow fungal growth. Pull whole CRT assembly out to prevent spilled/leaking glycol from onto lower main boards

Sep 04, 2007 | Philips Magnavox 51MP392H Rear Projection...

Not finding what you are looking for?

364 people viewed this tip

Ask a Question

Usually answered in minutes!

Top Televison & Video Experts

The Knight
The Knight

Level 3 Expert

73665 Answers

Cindy Wells

Level 3 Expert

5059 Answers

Electro Med Services...
Electro Med Services...

Level 3 Expert

6694 Answers

Are you a Televison and Video Expert? Answer questions, earn points and help others

Answer questions

Loading...