LG 50LN5700 has horizontal bands (2 or three) of what looks like high frequency noise that pop on and off the screen at regular intervals.

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.

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

See about firmware updates, http://www.lg.com/us/support-product/lg-50LN5700
If you cannot update the firmware then the main board is bad and must be replaced /

What is there to fix? You have now access to a larger interval of tunable frequencies. There are two or three selectable FM ranges. In Japan you can tune between 76 MHz and 108 Mhz. In North America the range is between 87 Mhz and 108 Mhz. There is 3rd one called School Band but I do not recall the limiting values.

First of all try, changing the input device to some other and see whether you see the same problem. Then connect your present input to a different TV and see. If you feel the input is ok, and it is a problem in the display, this is a case to be handled by a qualified service technician.

Hi Ethan,

What you're looking for is called a "crossover". A crossover is an electronic filter for an audio or speaker circuit. In an audio circuit, a crossover is used to prevent or pass certain frequencies or a range of frequencies from passing through it. Since your sub will reproduce the bass or low frequencies, you don't want other speakers to reproduce them. A band pass filter on your door speakers will do this for you. A band pass filter passes only a range or "band" of frequencies and blocks those that are above and below the range or band of frequencies selected. Installing a band pass filter will prevent the very high & very low frequencies from getting to the door /dash speakers. Likewise, you should consider connecting a low pass filter to your subs, too. The low pass filters work a little differently from of the way band pass filters work - they only allow low frequencies to get to the sub - blocking all the other higher frequencies (your other speakers are better suited to reproduce those). Lastly, you would install a high pass filters on tweeters. Tweeters are designed to reproduce only the high frequencies - sending mid and low frequencies to them is wasting power and can cause damage to them.

You purchase the filters for specific crossover points (the block / unblocked point) as determined by the individual speakers. If a sub has a frequency response of 20Hz - 100Hz, a low pass filter of 100Hz would be ideal. Remaining filters would need to begin at 100Hz - assuming the mid-range speakers have a frequency response beginning at 100Hz. A band pass filter of 100Hz - 3KHz would fit the bill nicely if the mid-range speakers go up to 3Khz Match the high end of the band pass to the high end of the frequency response of the mid-range speakers. Next, a high pass filter at 3KHz would allow only the high frequencies to your tweeters. Basically, you want to have the entire audible range 20Hz - 20KHz covered by the speakers and have the crossover points that match the frequency response ranges of the speakers.

I hope this helps & good luck!

If you wish to get some details; visit the site linked here. Pull up older posts.
http://electronicshelponline.blogspot.com/
Line faults & possible causes to LCD & Plasma screen are given with illustrations. You can get an idea about the fault to an extent. Faults to all LCD & Plasma screen are similar, irrespective of its brand and screen size.

i experienced a tainted vertical black lines on the boths sides of my lcd screen. There was no scratch or whatsoever that could be the reason why thsi balck colored vertical lines to spread. Hope you can help me solve this problem. Thank you..

The LG 44SZ21RB Have a problem with their light tunnel collasping due to the heat from the lamp. They are available as a spare part @ LG and would also require some silicon adhesive to bond it into the assembly. Very tedious job for any technican (2-3 hrs). Lg will not release parts to the general public only to an authorised LG agent.

The monitor may not be able to handle the settings of the video adapter. If you boot into safe mode (tap F8 key as the computer starts), does the display appear correctly? If so, then you just need to turn down the settings (resolution, color quality, frequency) to the lowest possible settings. If the display still appears wrong, then it may be something wrong with the monitor. You can try connecting the monitor to another CPU and see if you can replicate the results.