I have an SAMSUNG UN60EH6000F and when the main board is connected the backlights fail to switch on, any thoughts?

Hi Walter, I can help you with your TV issues. On Samsung TV's it's normal for the backlights to come on if the connector going to the main is disconnected, on most other makes this isn't the case however. This tells two things, the backlights themselves are working and the hot side of the power board is working plus the inverter, it sounds like you have main board issues, and it will need replacing, it's been the EEPROM that fails on this model, and it has the exact symptom you're seeing. Both parts can be purchased at shopjimmy.com, naturally the IC will be cheaper but replacing it involves advanced soldering skills and the equipment to do it so replacing the board may be your best best

Sounds like a mainboard/Digital board. Might be the panel too. Vizio makes substandard TVs and they tend to fail very easily. As much as I like to see devices repaired, this one may not be worth your hassle. Power problems caused by lightening can be the most damaging. You may even need both power and digital boards to repair it. I would buy boards from someone who will take them back in case the panel failed too.

Maegan,
You have already changed power supply/led board and main board. What is left now is the tcon and scaler board. Please try tcon.This may solve your problem. By the way, there is a systematic way of singling out the faulty board. A little research on this will save you save you time and money. Good luck.

Hi Matt,
The fault lies with the backlight LEDs. It is common with these sets. If you open the panel and replace the failed LEDs, or replace the panei.
Good luck.

Hi Frank,
Your TV has audio means the main board is working. You have not mentioned anything about the backlight. Most probably the backlight is not working in your case. If it is so, it is either some failed LED or LEDs in the array or a failed driver on the power board. Please check the drive voltage for backlight in on condition to confirm the inverter.

check all electrolytic capacitors (cans) in the power supply (the board the mains connect to for flat tops (if the can has a rounded top it has failed and, must be replaced

Hello!
Looks like pixels are appearing due to the failure of TV's main board. There is no "reset" button at all. the problem occurs due to fatigue failure of solder joints under main board's microprocessor. Technology has changed, but not in our favor! At computer motherboards, there is "zero insertion force" plug, which connects "micro" to the main(mother) board. It allows I.C. chip to be well connected to the circuitry, despite the difference in ambient temperature. Latter makes of TV's main boards using laser soldering of 100+ contacts to flat board via led-free solder alloy. after numerous cold/hot/cold cycles, the alloy becomes brittle and fails to connect all the pins of "giga chip" to the board. Plus: there is no such thing as a cooling fan or, even basic heat sink in most brands. "Disposal" technology! The only way to cure the problem is to replace main(signal) board, if your set is less than 3 years old. If more, there is a possibility of bad capacitors in a power supply. If the set hesitates to start up cold, that's the issue. But...? Couple month ago I did replace main board in 46" Samsung LCD Panel, due to the same reason. Looks like you are up to repair your set. whether it's a panel or D.L.P. the problem is beyond "reset"! It will only get worse over the time. Call for service or give me your model#. I might help you with part search and replacement procedure.
Thanks,
Alex.

That sounds correct, the main board is bad (the backlights ON signal is stuck low so it will not turn on the backlights board) and no way the repair shop will have the proper tools to do delicate surface mounted repair works. Mian board is not cheap, I would sell parts on EBAY nad spend the money on new TV.
I have seen less thane two years old TVs that go bad already, they do not make it to last.
Basic troubleshooting guide here:
http://www.fixya.com/support/r5093881-lcd_flat_panel_tv_troubleshooting_guide
http://www.fixya.com/support/r6150077-basic_lcd_monitors_troubleshooting
http://www.fixya.com/support/r7406380-tv_training_manuals
Failed TV and Monitors pictures: http://s807.photobucket.com/albums/yy352/budm/
Learn about bad caps: http://en.wikipedia.org/wiki/Capacitor_plague
Parts: www.shopjimmy.com
Capacitors kit: http://lcdalternatives.auctivacommerce.com/Default.aspx he can make you a set of caps.
Or www.digikey.com just make sure to use caps with low ESR, 105c, high ripple current, long life rating such as PANASONIC FM or FC series.

I'm afraid that while their intention was good, that most the posted solutions miss the mark. Let me guide you thru the diagnosis and possible cure. This is detailed and lengthy, since these points appear often in LCD TV/Monitor repair. You may wish to warm up your soldering iron and skip to Step (11) for the repair procedure.

(1) We know that much of the Main Power Supply is working since many of the audio, video and digital processing sections appear to be working (sound, remote control, tuner, and video out).

(2) We know that the Backlight Inverter is working. Even thought the screen appears to be dark, light from the backlight tubes can clearly be observed. Further, even thought the screen is dark, you *can* observe a small amount of the backlight thru the screen.

(3) When working on LCD TVs and Monitors, the typical problem is backlight failure. (Fortunately this is NOT the case here.) Backlight failure is most often due to Backlight Inverter failure, or Main Power Supply failure. Rarely do the bulbs fail outright (although occasionally thru abuse a CCFL tube is cracked or shattered).

(4) The typical failure mechanism on LCD TV/Monitors that have many in-service hours on them is CCFL tube aging. As the CCFL tubes get older they require increasingly higher voltages to maintain the proper regulated current thru them which in turn creates the correct light output. The higher voltage is often beyond the design limit of the Backlight Inverter leading to component failure. Typically discharge breakdown arcing on the output transformers (that drive the CCFL lamps), or drive transistor failure in the Backlight Inverter power supply. Alternatively, the Main Power Supply may fail. Typically the Main Power Supply supplies +12V, or +15V, or a higher voltage (+24V?) to the Backlight Inverter subsystem. Once again, as the lamps age, more current is drawn, and if the Backlight Inverter doesn't fail outright, it draws excessive current from the Main Power Supply leading to either Main Power Supply failure. Alternatively, the Main Power Supply protects itself by shutting down once the excessive current is detected. This can often be seen as "monitor cycling" where by a LCD Monitor will initially power up, but subsequently cycles every few seconds as the Backlight Inverter draws too much current causing the Main Power Supply to shut down. Then, after a brief recovery period, the cycle repeats.

(5) Another failure mechanism, that should not be overlooked, is Electrolytic Capacitor failure. The Internet has many sites documenting either manufacturing defects in Electrolytic Capacitors used in any of the subsystems (Backlight Inverter, Main Power Supply, Digital Signal Processor, etc.). However, more often than not, Capacitor failure is due to component stress-due to the high ripple currents present in inadequately designed switching power supply subsystems. Additionally, many inferior Electrolytic Capacitors of Chinese origin are inadequately designed-they lack trace chemicals in the Electrolyte necessary to assure long service life.

(6) If you suspect any of the mechanisms described which cause an absence of CCFL backlight, you can often use a small pocket flashlight, and observe the screen image *is* in fact present on the LCD panel, but in the absence of sufficient backlight, you mistakenly believed the LCD panel to be dead.

(7) This is not the case here. We can clearly see that the CCFL backlight *is* lit, but we also do *not* observe any image on the LCD panel, even with an external flashlight.

(8) Thru this diagnosis of exclusion we assume that either the LCD panel itself is defective, or that the LCD panel is not receiving the correct drive signals from the Digital Signal Processor subsystem.

(9) A cursory examination reveals that the Digital Signal Processor board is producing output activity, which-even if malfunctioning-would likely produce some sort of LCD display activity.

(10) The LCD panel is totally dark (backlight is on, but no image at all). This failure is so absolute, it leads one to suspect power related problems as opposed to logic or drive problems.