Tip & How-To about Televison & Video

SONY TRINITRON ONE COLOUR PREDOMINANT SCREEN

Sony Trinitron sets are of CRT [Caothde Ray Tube] types. The common fault seen in these type of TVs are any one colour predominant on screen wih sound OK. Either red, blue or green colour with some thin horizontal lines at about an inch apart will be seen on the entire screen. This is totally a display card problem, which can be seen pluged onto the picutre tube neck. There are three electron guns for every picture tube, which emits red, blue, and green beams, which in turn illuminates the phosphor on the screen to get that colour. If no emission from all guns, results in a blank screen, ie black screen without any disply at all. The three colour beams together produces proper coloured picture what we see on screen. These three gun's terminals are brought out by pins of the picture tube outside to which video signals are given in appropriate proportion to produce a TV picture. Normally, all these three pins are biased with a voltage of about 170 to160VDC+ve. Take one colour gun, as an example and and let me describe the problem.
Let it be a green gun. These guns are called cathodes of the picture tube. If it gets a voltage with respect to its grid, it will emit electrons according to the voltage applied to it. This is a negative process, that is, as the voltage at this pin drops, its emisson incresses and vice versa. If the emission increase, the colour with respect to that gun also will increase and gets predominant at the screen. So when we see a green predominant screen, there will be less voltage at the green cathode with resepect to the other two. If red colour is predominant, the voltage at red cathode will be less than the other two. If blue colour is predominat, the voltage at the blue cathode will be less than the other two.
We must find out the reason for this fault first. Assume that your Tv has a red predominant screen with some thin lines across it, at about one inch apart of the entire screen, it is clear that the the red cathode voltage is very lower than the other two. the main reason for this fault, normally seen in most of the Sony Trinitron, are loose soldering points either to the picture tube base socket or the resistor connected between the red drive transistor's collector point. Resoldering the most of these points on the base card by applying a little more solder will rectify this probelm. Other possibility is shorted video output transistor of that cathode. A direct short [collector to emitter] of these transistors will drop volatge to very low at that respective cathode of the picture tube, and that colour will be pridominant along with lines. Replacing the transistor will solve the problem. In some cases, the resistor connected to that transistor may have blown out. If so, it should alo be replaced. Whatever the case may be, voltage at the respective cathode that emits colour will be very low with respect to the other two. Find out the reason and rectify it. You can compare the voltages of the other two cathodes with respect to the faulty colur cathode. Cathode pins will be marked on the base card, and can be identified. It is best to pull out the base card from the picture tube neck and place it somewhere a safe place without shorting it with other parts of the TV. You can measure the voltages of these points very easly, without fearing the damge to the picture tube. After all are found Ok, replug the base card and switch on the TV. The set will be alright. In rare cases, chroma IC also can be a reason for this fault. if it is faulty, after a short period after switch on the TV, the IC will overheat and shutdown the entire system.

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sony trinitron tv


Check the video output section circuit for any loose solder or damaged component/s. Re-solder all the suspected solder terminals at this board, by applying a little more solder. This board can be located at the neck of the picture tube, will directly plugged on to it; can be pulled back to separate it for repair. The fault is knows as one 'one color predominant' screen. If you wish to get some details, check the site linked here. http://electronicshelponline.blogspot.com/ Pull up older posts.

Dec 25, 2013 | Televison & Video

1 Answer

Regza 5Toshiba) V55 TV - picture tinted red. First the picture went (sound ok), when I got the picture back by fiddling with contrast and colour settings, the picture was red. I've used the 'colour temperature' settings to improve the picture, but the red tint is still there. Any fixes?


The fault is with its video output stage circuit. The fault is called "one color predominant' screen. In most cases, this might be to a loose solder terminals at the video output stage circuit board. This board can be located at the neck of the picture tube, will plugged on to it directly. If you wish to get more details, check this link. http://electronicshelponline.blogspot.com/ Selecting the view option, either to Mosaic /Timeslide, can be selected by the drop-down list, by the top left of the display window, will make surf easy. You can also do a search, by type in the brand name / model number / IC used, in the search box at the top right of the display window.

Nov 05, 2013 | Toshiba 36A41 36" TV

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sony trinitron


Check the video output card for any loose solderng, especially to green video output stage. This is a common fault to Sony TVs. The video output card can be located at the back [neck] of the pricture tube, will directly plugged on to it. If you're sound in electronics, and wish to get more details, check this link. http://electronicshelponline.blogspot.com/ Selecting the view option, either to Mosaic / Flip card, can be selected by the drop-down list, by the top left of the display window, will make surf easy. You can also do a search, by type in the brand name / model number / IC used, in the search box at the top right of the display window.

Nov 02, 2013 | Televison & Video

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colors of my sharp21 sn5 tv are only green colour,can i correct this colour problem


If you wish to get more details about this type of fault, and its rectifications, visit this site. Details are there. Pull up older posts. This fault is technically called as one color predominant screen, and can be rectified, if you have some knowledge in electronics.

Mar 24, 2013 | Televison & Video

1 Answer

Sony Trinitron screen turned pink


Hello
Absence of green is the problem. You see mixing of red and blue, which will look like pink.
the fault must be of its video output card. This card can be located at the neck of the picture tube. Check this card, for any loose solder. This is a common problem seen in most CRt based Sony TVs.
Just resolder all the suspected solder points on this board, by applying a little more solder, without making any solder bridge short in between adjecent solder terminals.
images of two models of sony trinitorn TVs, [back cover opend] has been attached here. you can see the boar under suspection, along with the picture tube neck. [See the rectangulat printed circuit board attached to CRT base]3_9_2012_2_12_06_pm.jpg3_9_2012_2_12_38_pm.jpg

Mar 08, 2012 | Sony FD Trinitron WEGA KV-27FS120 27" TV

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