Question about LG Flatron F700B 17" CRT Monitor

1 Answer

LG F700B Lines at top of screen

When first powering up the monitor when cold, I get a series of horizontal lines in the top 2 inches or so of the screen.
The picture at the very top of the screen appears to be slightly "Folded Over".
After warming up for around 10-15 mins the problem seems to correct itself.
I am assuming a cap is drying out, the problem is-which one?
I don't have a schematic, but if someone could give me an idea of where to look, I'm sure i could replace the component and save myself a nice little repair bill.
The monitor is around 6-7yrs old.


Posted by on


1 Answer

  • Level 1:

    An expert who has achieved level 1.

  • Contributor
  • 1 Answer

i have same problem (exactly same!!)
see here i hope it is usefull
if it solve your proble please notify me

Posted on Jul 27, 2009


1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

A 6ya expert can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
The service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
Good luck!

Posted on Jan 02, 2017


Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

So I have a 50 Lg ( LG 50LN5700). There is still a picture however about every 3 seconds it goes from regular to blurry and repeats. There seem to be about 3 black lines across the top horizontally about 3...

To clarify, are the 3 black lines horizontal (left to right across entire width of screen)? or are the 3 black lines vertical (top to bottom across entire height of screen)?

Horizontal lines are almost always the result of a failed panel, and no board replacement will fix the issue.

Vertical lines such as you have described (only 3) are probably also a bad panel. If the black lines were evenly spaced in a repeating pattern, it could be a mainboard or TCONN board.

Has this panel been cracked? or perhaps cleaned recently with too much water or cleaning solvent that has gotten the screen wet?

You may have to sell the TV for parts.

Oct 23, 2017 | LG Televison & Video

1 Answer

How to fix horizontal lines on LG TV

Not sure if this is recent but in settings adjust picture size to fit. Top to bottom side to side.
sounds like you are seeing what are called retrace lines

Sep 30, 2016 | LG 50" 5700 Series LED HDTV - 50LN5700

1 Answer

2 days ago, a narrow black horizontal line appeared in the middle of the screen.

Samsung LN46B650 Thin Black Horizontal Lines - Forums - CNET > Forums > Samsung

CNETJun 11, 2015 - I'm experiencing thin black lines from the top of the screen to the bottom. ... my lcd tv has multiple lines are horizontal it starts from the right and fades too the left, ... Samsung LN55a950 - Horizontal lines on right side - Forums - CNET
Jun 11, 2015
Samsung 52" LCD TV black lines - Forums - CNET -
Jun 10, 2015
More results from

Plasma TV Repair Horizontal Lines - How to Diagnose ...

? 2:49
Sep 2, 2014 - Uploaded by
I have thin horizontal black lines on the top and bottom areas of my TV. .... Hi, I have a 2011 64-inch 3D Samsung PN64D8000 Plasma TV.

how to fix horizontal or vertical lines on lcd tv - YouTube

? 4:52
Apr 12, 2014 - Uploaded by cr4zyw3ld3r
Hi my LG 47ln5700 tv set has thin greyish black horizontal lineson one side of the .... I hope this works good with Samsung LCD as well....

Dec 19, 2015 | Samsung HP-R5072 50 in. Plasma HDTV

1 Answer

Horizontal lines across tv

If your LCD TV or monitor has stopped working, or is displaying one of the following
symptoms, then it's a candidate for some new capacitors
- Flickering screen
- Screen image disappears after several seconds
- Dim screen
- Slow start
- Power LED on, but no picture
- Unusual colors and/or lines
The primary cause of LCD TV and monitor failure is caused by faulty capacitors. You can
examine the capacitors in your LCD TV or monitor and actually see if they are bad.
If they appear bulged on top, then they need to be replaced.
New capacitors will solve a host of problems in LCD monitors and TV's and will extend the life
of your monitor or TV by several years.
Check the cables, connectors and connections.
Take it to a repair shop.

Apr 12, 2014 | Sony Televison & Video

1 Answer

Horizontal lines have started appearing, running all he way across the monitor screen....several close together abour 3 inches from the top, and one, sometimes two, about an inch from the bottom... I have...

what you are seeing ithe horizonal sync lines, have you tried to adjust the settings on this monitor, I would try turning down the brightness, and the contrast. There should be a menu button on the monitor to adjust it.

Nov 18, 2010 | Soyo DYLM2286 Monitor

1 Answer


Push the button on the Monitor to activate the OSD (On Screen Display). With the OSD, one can "stretch" the picture (horizontally/vertically) and "move" the picture (horizontally/vertically) in order to "fill" the viewable area with your compueter's output.

May 09, 2010 | LG Flatron F700B 17" CRT Monitor

1 Answer

KDSusa Analog monitor

I would check the video card , then the connector and if the lines are still there , then you need to replace the monitor

Jul 26, 2009 | LG Flatron F700B 17" CRT Monitor

1 Answer

LG f700b raster problem

If the lines are slanted, you are seeing 'retrace' of the horizontal sweep. The distortion at the top is probably caused by a failing electrolytic capacitor in the vertical deflection circuit or in the power supply filtering for that circuit.
If you want to try to find this problem on your own, use great caution! There are exposed parts that can carry very nasty if not fatal voltages.
Go to any electronics parts source and buy two cans of 'freeze spray.' Expect to pay $4-5 dollars each for them. Using this on a 'live' monitor makes it still a little more hazardous since the cooled parts will form frost that may be conductive and I recommend keeping one hand behind your back so even if you touch something 'hot' you won't have currents passing through your heart.
With the rear case removed, you might drape a clean towel over the guts to let it warm up as it would if cased. When you notice the distortion going away, remove the towel and start spraying short bursts at the cylindrical parts, mostly those of 'medium' size ranging from ~ 3/4 to 1 1/2 inches in height and 1/2 to 3/4" in diameter. These are the parts with values most likely to be failing.
If you can identify the power transformer, a largish block, mostly black, check those capacitors first. You will need a mirror to watch the screen for the worsening of the distortion again and be patient; the parts you are cooling have some thermal mass so the effect is not immediate.
If you find one that seems to affect the picture, then, if you have one, direct a hair dryer (blower type) at that area to see if you can recreate the problem several times.
If you can isolate one specific part, note the value of it; it will have several printed items: - Capacitance - this will be such as this: '100 uF' - Voltage - '63V' - Polarity - this will be marked with a '+' and maybe a minus on the other leg. This is important! Any new part must be installed with the correct polarity if any is shown and it will be present on this type of part.
These parts are very inexpensive so if you cannot decide which one is at fault, replace all of them in that area; they cost from 20 cents to a buck. If you have no local electronic parts store (Radio Shack doesn't have much any more) you can order them from Mouser Electronics. Mouser has NO minimum charge and adds only real postage/shipping charges. You'll find them at
If you decide to go this route, you will have to acquire and learn to solder with a soldering iron. Or if you have a friend who is an amateur radio operator, they will probably do this for you.
Removing the board from the bottom of the case is pretty easy, just make sure the monitor has been OFF for a while otherwise removing the thick cable from the CRT will be a really memorable experience!
Looking at the bottom of the board, note the look of the other solder joints there and do your best to duplicate them when installing the new part(s), bad solder joints can make your repair futile.
Or, you can stuff the wole thing in an envelope and send it to me ;-)
If you have been happy with this unit, it is worth the repair, since LCD monitors are often dead soon after the warranty has passed on.
Good luck

Jul 26, 2009 | LG Flatron F700B 17" CRT Monitor

1 Answer

I have a Dell 17" LCD monitor with a horizontal band.

You would better served replacing monitor you can buy one for about $100-$120 dell if you lie has one for $99

Mar 01, 2018 | Dell Computers & Internet

Not finding what you are looking for?
LG Flatron F700B 17" CRT Monitor Logo

166 people viewed this question

Ask a Question

Usually answered in minutes!

Top LG Computers & Internet Experts

Doctor PC
Doctor PC

Level 3 Expert

7733 Answers

Alun Cox

Level 3 Expert

2678 Answers

Les Dickinson
Les Dickinson

Level 3 Expert

18424 Answers

Are you a LG Computer and Internet Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides