42la20h flickers when i power on and i can hear buzzing sond in back of unit

I would look to see if this unit has a back light and if so it may be your problem--either the actual back light or the voltage source that powers it.

Not likely to be a do it yourself repair.

jglendenning, If not into soldering irons, solder, meters, and electronic repair of "switch-mode-power-supplys/cold-cathode-fluorescent-lamp ballast-circuits" then trade for new unit! Retrevo .com lists K717s as time to retire unit. Before you do anything check out the longer and more useful video clips at YOUTUBE that deal with "lcd monitor disassembly" and "lcd monitor repair" FYI so you at least know what is inside a typical desktop CCFL back-lit LCD monitor. 99% use same basic design and principle of operation no matter what brand of unit you have or will purchase in future!!! Hope this helped some. 12fixlouie

when the screen is black and the power light is steadly lit, shine a flash light at the screen. if you can see something, the inverter board is bad and the back light cannot turn on. if the power light flickers, reseat the power plug and put your ear to the back of the monitor where the power plug is. if you hear a buzzing or any high pitched noises; the power supply is bad. use the macufactures warranty for repairs.

most of fuel pumps were in tank, wire corrodes is harness under right front seat floor pan to tank
if fuel pump buzz is heard and car runs and when it doesnt run you cant hear the fuel pump try
turn ignition off wait 10 seconds
turn ignition to on position to (prime or hear pump buzz)
no buzz fuel pump not working check fuel pump relay(swap with another) and try again?
you could use test light to pump wiring and make sure your getting power to pump on this prime test no power relay or wiring problem.
power at pump, but no buzz fuel pump faulty

This sounds like a power supply problem, how old is the monitor? If it is not new in the last year and is used regularly it sonds like a faulty capacitor in the power supply. If you are aware of the precautions necessary when handling capacitors and a moderatly competent solderer then you can replace then yourself - a complete set of capacitors usually costs around £3 or $5

Disconnect the speakers and see what happens. Carefully examine the speaker cables for unwanted connections (shorts).
Take a clue from when the power problem appeared. Something was moved and made the buzz a (probable) dead short.

The compressor is not coming on and some part of that unit has failed. Do you hear any clicking sounds along with the buzzing sound? Recommend that you shut the unit down (remove power from it) until a service tech can listen to it try to start up.

The power company-installed load management system is probably a red hearing. That system will either fully turn off the unit or allow it to turn on/start up.

If you have a capacitor tester.. i'll be much better at least you would know which caps that actually failing..
I would replace all the caps if you dont have the tester.. and while your at it. try to resolder connections and some parts like transistor etc.. maybe they have "cold solder"

this is the transformer that is doing it and it may end up failing soon , and should be replaced before any other dammage is done,

When we turn our TV the humming and buzzing begins! We cn mute it and it goes away and then it when we turn the sound back on the sound is back! How can we fix this?