VERTICAL HOLD CONDENSED TO SINGLE LINE IN MIDDLE OF SCREEN.USED TO ROCK IT TO GET FULL SCREEN,BUT THAT NO LONGER WORKS. I KNOW THE CHIP IS LOOSE BUT I DONT KNOW WHERE IT IS SO I CAN REPLACE IT.

Vertical scan output section circuit fault. Absence of vertical scan causes the single horizontal line on screen. Horizontal scan output section is OK. Contact any service technician to troubleshoot the vertical scan output section circuit. If you wish to get some details; check the site linked here. Pull up older posts.Surf the site with patience.http://electronicshelponline.blogspot.com/
Horizontal line fault to CRT based TVs are given.

there is a single ic you need to find, usually location ic301 or 401---it will have between 7 and 13 pins in a single straight row---a generic number is printed on the front---usually begins with a LA but can be different

Locate the chip and gain access to the bottom of the board, the pins on the chip break loose from heat==SOLDER ALL THE PINS BACK AND YOU SHOULD BE GOOD TO GO---its a very common problem in these sets.
something like this with more pins possible--will be attached to metal of some sort to keep it cool.

If it has a white line in the middle running left to right the problem is in the vertical circuit.

This can come with age as solder connections (this is the most common cause) come loose or break at the chip in that circuit.

Much of the time with set on a good hard rap on the top or side and the line will try to open and return a full picture.

Someone who can get to it and can solder can fix that---the chip will usually have 7-13 pins and be mounted on a metal plate that is fairly small(it keeps the part cool)---fixed a lot in less than ten minutes.

You will have to open the set, locate the chip(usually a location number on top of board by it will be something like IC301 or 401).

Most of the chips will have a generic number on them a LA------ or such. You will have to remove the board to look at the bottom where the chip solders in.


I attach a photo of a typical chip.
Let me know if questions

If its a horizontal line in the middle of the screen do not switch on the TV till you fix it. It means you have lost the vertical amplifier IC ( chip ). If you continue to turn on the TV the phosphor in area where the line is coming will get permanently burnt and do not look at the screen it can cause retina ( eye ) damage.
Take professional help to replace the chip.

Hello

Your TVs vertical swee sction has failed. All CRT based TVs have both vertical and horizontal sweep sections to sweep the picture both in vertical and horizontal direction to display it on the picture tube screen. This process is otherwise called as scanning. If vertical scan section fails, you will see a horizontal line at the middle of the screen and if horizontal scan fails, you will see a vertical line on the middle of the screen.
You have to open your TV to retify this fault, as the fault lies in the internal circuit board. Open it after disconnecting it from the mains wall socket, and locate the vertical output section inside. It is very easy to locate. On opening you can see a coil fitted on the neck of the picture tube, called deflection yoke, and there will be four wires from it goes to the main board. Out of which two of them will be thick, and the other twos will be thin. The thick wires are usually colour coded as red and blue. Just follow the two thin wires. You will reach to a plung in socket to which these four wires together connected. Turn upside down the circuit board, and follow the print track through the print side of the above said two thin wires connection goes. it will go to the vertical output section.
Before doing any thing, first look into the circut board for any loose or bad solderings are there. It is a common fault that this section have loose solderings on it, because most of the components will heat up while working. Repeated heating and cooling, make loose soderings to emerge.
Resolder all the suspected points, as loose solderings will be microscopic,a nd acnnot be detected very easly. We in the service field also will fist do this.
Usually vertical output section is composed of an IC related circuit. Solder all pins of that Ic first and feel the effect. If this does not help, desolder the IC out of the board, will be screwed on to a metal heatsink, go for the same type and number. Replacing the IC will solve your problem.
If you wants any more assistance, feel free to contact me through Fixya. OK.

It sounds like a loose solder contact in the vertical circuit.
maybe on the vertical ic or some caps in the area.

Hello,
Sounds to me you have a cold solder joint ( loose solder connection ) on the printer circuit board around or on the vertical chip or on one of the vertical capacitors. You may also have a bad vertical chip or a bad vertical capacitor, but I doubt it since it did come and go. I'de get a soldering iron and some solder and touch up the connections. I will remind you that you need to always excersise saftey by making sure, before removing the back, unplug the TV from the wall, and use care not to come in contact with the large red wire going to the back of the picture tube as the picture tube can be turned off and still store lots of voltage ( up to 35,000 volts). Always stay safe and when soldering, use care not to run solder across places that will make a short.
Good Luck and I hope this helps
Ed Meshechek ( Radio Man )
NC Electronics
Mills, Wyoming
307-266-4675

This is not an "STK" problem. Your problem is VERTICAL. You need to check your vertical chip for damage CN301 and check around it for any bad parts or loose connections. I've seen loose connections on the chip itself cause it to self-destruct.

If the line goes across the screen you have a loose solder joint on the vertical output IC. I've seen this happen many times in Zeniths and a lot of other sets. If the IC is not loose then there is a loose solder joint somewhere else in the vertical circuit. These IC's are 10 - 13 pin chips that operate the vertical deflection on your set. I feel like a drop of solder in the right place will fix it! Stargazer

You have a bad component in the vertical circuit of your set. If you hit it on the back of the cabinet with your hand which will "jar it" and the picture flashes back on then you have loose connection. If nothing happens then the vertical circuit has a bad component most likely the Output IC. (Chip) Stargazer