Question about Coby CX-TV1 5 in. Portable Television

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Thin white horizontal line center of screen!

Hi, need some help please...Almost complete black screen, only one thin bright horizontal line in the middle. I already cheched some capacitors and resistances in the vertical output, all seems fine. Any ideas? Thanks.

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Re: Thin white horizontal line center of screen!

The set should have a vertical output IC,You need to change it ,maybe you can check the B+ going to it because it might have opened the safety resistor if the IC went bad.You can check for broken board too unless the set is never move from one place.Be carefull when checking voltages ,there is still high voltage,not much but can num your whole hand.

Posted on Oct 18, 2006

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Lines across the top of screen

If this is a picture tube set (not a thin screen), then you have a bad electrolytic capacitor in the vertical circuit. Just about all picture tube sets that I've worked on that get lines at the top was caused by a bad or leaky cap and is a common problem w/ most sets. There's a very slim chance it could be the vertical ic but normally when it goes bad you will have nothing but a thin white line running across the center of the screen from left to right. If it's just a capacitor, the part would only cost a couple of dollars at most, however there's no way I can tell you exactly which one to change w/ out looking in the set. A repair shop would probably get between $30-$50 to fix it. If you can give me the model number of the tv, I can see if I can you some more info.

Jul 28, 2010 | Sylvania Portable Televisions

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Have a 29 inch 5 or 6 yr old rca color tv lately we get a colored horizontal bar across the top of the screen and the other day we have fuzzy black lines across the entire screen


CAUTION: To prevent damage to the CRT phosphors, immediately turn down the brightness so the line is just barely visible. If the user controls do not have enough range, you will have to locate and adjust the master brightness or screen/G2 pots.

A single horizontal line means that you have lost vertical deflection. High voltage is most likely fine since there is something on the screen.

This could be due to:

Dirty service switch contacts. There is often a small switch located inside on the main board or perhaps accessible from the back. This is used during setup to set the color background levels. (On some sets, this is located on the CRT neck board and may be a jumper plug or other means of selecting service mode - not an actual switch.)

When moved to the 'service' position, it kills vertical deflection and video to the CRT. If the switch somehow changed position or got dirty or corroded contacts, you will have this symptom. Flip the switch back and forth a couple of times. If there is some change, then replace, clean, resolder, or even bypass it as appropriate.

Bad connection to deflection yoke or other parts in vertical output circuit. Bad connections are common in TVs and monitors. Check around the pins of large components like transformers, power transistors and resistors, or connectors for hairline cracks in the solder. Reseat internal connectors. Check particularly around the connector to the deflection yoke on the CRT.

Bad vertical deflection IC or transistor. You will probably need the service manual for this and the following. However, if the vertical deflection is done with an IC, the ECG Semiconductor Master Substitution guide may have its pinout which may be enough to test it with a scope.

Other bad parts in vertical deflection circuit though there are not that many parts that would kill the deflection entirely.

Loss of power to vertical deflection circuits. Check for blown fusable resistors/fuses and bad connections.

Loss of vertical oscillator or vertical drive signals.

The most likely possibilities are in the deflection output stage or bad connections to the yoke.

May 30, 2010 | Portable Televisions

1 Answer

Coby Tv Screen Wiggle and vhold makes it worse

Hi I am Vortash I gather you mean by wiggles that the picture tears sideways .. if this is correct this is called Horizontal tear .and the Vertical Hold control will not do anything to adjust this . If there is not another button for the Horizontal Hold then you will probably have a scan fault that needs to be seen to , it could be just dry joints more likely a capacitor is drying out and needs replacing on the Horiz sync circuit a common fault but if you're not electronically minded or trained will need an engineer to fix it .. regards Vortash

May 31, 2009 | Jensen 5'' Black and White Flat Screen TV...

1 Answer

Onida 14'' tv on screen showing blue line


Jan 16, 2009 | Portable Televisions

1 Answer

Horizontal white lines across top of TV screen

Vertical hold circuit is failing.

Check capicitor in vertical hold circuit. You should have solid knowledge of electronics repair before attemping repair. TV's can emmit harmful radiation, and produce voltages up to or in excess of 30kV.

Oct 07, 2008 | Portable Televisions

1 Answer

TV - Thin horizontal line picture on screen

Is this a LCD TV? IF it is it could be something on the video processing board. Let me know the model # and well will go from there. Thank you Jay

Jan 31, 2008 | Portable Televisions

1 Answer


Check components around the flyback transformer. Especially small value resistors and diodes. Also check the solder joints on the flyback transformer. Please be safe and unplug set when checking parts, also discharge caps or wait a while after unplugging.


Jan 24, 2008 | Portable Televisions

1 Answer

I can only see a line

thats a vertical problem.the vertical ic needs to be changed or some other component associated with it. have a tech check your set for repairs.good luck

May 02, 2007 | Philips PR0930X 9 in. Portable Television

1 Answer

POP and noothiing

yes it can still be fixed! the pop sound you've heard maybe came from a blown capacitor in the vertical deflection circuits. this symptom, sometimes called the tube light effect, it is characterised by a bright thin horizontal line across the middle of the screen. this symptom is caused by a breakdown in the vertical deflection circuit. hence maybe the trouble maybe in the vertical oscillator, amplifier or output circuits. but if all i have said is not clear to you, better bring it to a qualified tv technician. good luck!

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