Tip & How-To about Televison & Video

One amoung the Primary Colour Loss with Sony Trinitron TVs

The fault is mainly due to the video output section of the TV. The video output section can be located at the neck of the picture tube. The board that directly plugged on to the neck of the picture tube is its video output board, which can be detached out from the neck of the picture tube, by a straight backward pull.. Pull it straight forward, don't make any sideward or upward downward motion, as it may damage the connection pins of the picture tube. There are some hi-watt resistors and video output transistors,[ 3 of them to amplify three primary colors]. In some sets, this section will be composed of an IC. If ic is used, there will be no transistors at all. The most common problem for lose of one primary color to this type sets are loose solder points. The components in the video output section will heat up while working. Repeated heating and cooling may make the solder terminals of these components to get loose contacted.
Normally, some of these loose solder points are very minute, microscopic, to detect by normal vision. Some of them can be detected. Just do what we service technicians do, when we come across this kind of fault at service table. Just resolder most of the suspected solder terminals, by applying a little more solder to each point, without making any solder bridge short in between adjacent solder terminals. This must solve the problem.
If not, check the strip wire connection terminals that comes from the main board to this video output board at the picture tube base for any loose contact. Check its other end too, which is connected to the main board. These wires are the carriers of the RGB signal voltages. If there is some loose with this wire contacts, or a break in this strip wire, also may the cause of this primary color loss problem.
If there are no problems as said above, the chroma IC is faulty. There is no other way than replace it with same type and number.

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sony tv

Check the video output circuit for any loose solder terminals, especially to the 'collector' terminal of the green video output transistor. This section circuit can be located at the neck board, directly plugged on to the picture tube neck.

Jun 21, 2013 | Televison & Video

1 Answer

no green on tv

The green output section [green video output] section to your TV should be checked. Even a loose solder terminal at this board can cause this fault. The video output card can be seen plugged onto the neck of the projection tube.

Oct 20, 2012 | Panasonic TX-42PT10 42" TV

1 Answer

My Picture is coming and going every few seconds. Screen goes black. Picture color is no longer good, its greenish now.

I assumes that the fault is only with the picture, but sound output is normal. The fault you describes here is due to some loose solderings at its video output board. The video output board can be located at the neck of the picture tube itself, directly pluged on to it. It can be detach out from the picture tube, by applying a little backward force. Be sure no to make any sideways movement, as it may damage the pins of the picture tube. Pull it straight back to get it detached.

gopakumarg43_71.jpgJust see the opened view of your wega tv. Here the main board is placed vertically over the CRT base board [video output board]. Behind this board, you can see a small square board with some components on it soldered directly. Pull out that board from CTR base. Just look fit for any loose solder points. Normally it will be difficult to detect these solder loose points, as some of them may be microscopically small to view out. So, just do, what we do to it at service table. Just resolder all the suspected loose solder terminals including the solder terminals of picture tube base socket, soldered diretly to that board; by applying a little more solder, without making any solder bridge short in between adjecent solder terminals. This must solve the problem of you TV. You should have a concept of soldering and a good quality soldering iron and solder wire to do this work.
I'm not an English. My mothertoungue is entirely different to that of English. So co-operate with my language please. I'm only trying to transfer my ideas and experience that I got from the last 40 years of TV servicing.
If you want any more assistance from me, feel free to get me by Fixya. OK.

Sep 16, 2011 | Sony FD Trinitron WEGA KV-27FS100 27" TV

1 Answer

when I turn on tv,it shows a white screen and don't anything do

You haven't specified anything about your TVs sound condition. If the sound is there and only the picture is out, leaving a white screen behind, it is due to the R-G-B output section of your TV. The section mentioned above comes on the picture tube base card, a circuit board connected on the neck of the picture tube, directly pluged onto it, with the help of a socket called picture tube base socket. You just measure the voltage to it first. The main voltage comes to it from the secondary voltage winding from the line output transformer, [LOT], generally, or from the SMPS power supply itself. It will come upto 260VDC, and must be there. If this voltage is missing, the fault you mentioned will occur. If this voltage is there, the fault may be due to a decective video output section. It may be built in with transistors, or an integrated circuit [IC].
Usually, Samsung uses Philips IC, number [TDA 6007B], or its equivalent in this stage. Check for any loose, or bad soldering on the terminals of this IC. I advice you to resolder all the pins of this Ic, by applying a little more soder, without making any short circuit bridges in between them. zin most cases, this will solve the problem. If it doesn't help, replace the IC with an identical in type and number.
If you wants anymore asistance, feel free to get me through Fixya. OK.

Dec 20, 2010 | Samsung CSN2077 20 in. TV/DVD Combo

1 Answer

there is about a four inch wide bar at the top of the tv and the part of the pitcher in it is upside down

That fault is called vertical foldover, and it is mainly due to some fault in the vertical output section inside the circuit borad of your tv. It may be due to some capacitor problems or an Ic fault. To rectify the problem, you shoud open your tv. Take every precautions before opening the tv, while we take working with an electrical equipment. As high as 30,000VDC points are there inside your tv, while it is working, or even after that, the picture tube's final anode will have a charge equal to the voltage said above, for a long time, you should be very cacutious.
Open your Tv, and locate the vertical output section. It is easy to locate. As you open your tv, you can see the vertical deflection yoke, the coil fitted around the neck of the picture tube. From it, there will be four wires going to the main printed circuit board, out of which, two will be thick, normally red and blue coloured, and the other two will be thin. Follow the the two thin wires, you will see it to be connected to a plug in point on the printed circuit board. just upside down the printed circuit board without distrubing any of its plug in connections, and follow the underside circuit track, and it will guide you to the vertical output section.
There you can see an Integrated Circuit, otherwise known as [IC], screwed onto a metal heatsink, to radiate the heat out ot it while it is working. Just resolder all the leg solderings of that Ic first, and switch on the tv to find there is any change to the vertical foldover. Usually these points will get loose contacted, as they are heated and cooled repetadly. Sometimes this process may resolve your problem.
If not, change the supply filter capacitor, that filters the input supply voltage to that IC. It is best to change the filter capacitor said above, and all the capacitors in that section, which will not cost too much. When replacing capacitors, keep a keen look on its polarity, where electrolytic capacitors ahve positive and negative legs marked on it, it should coincide to that of the markings on the printed circuit board, otherwise there is a chance for them to explode out.
You just concentrate only on this section inside your TV, since the fault is surely there. Just proceed with confidence. You will and you can. Wish you sucess.

Nov 17, 2010 | JVC AV-32D305 32" TV

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