Hi I have a samsung lcd tv (LE40R7) The picture has started to break up (Pixelate) generaly at night after seven. It is connected to a virgin V+ box only No terestrial. Could it be something that a neighbour is using? Sometimes when I switch the tv on where the words menu etc appear there is just red dots.

Joao Pedro

• 155 Answers
• Posted on May 03, 2008

SOURCE: Samsung LCD Tv

Try this:
Access menu service by press on your command, with your TV OFF:

INFO + MENU + MUTE + POWER ON

Then you should get access to Service Menu.

The last item says: RESET

This will do a reset to the TV.

Make no harm.

WARNING: If when on service menu you feel tempted to "screw" on anything FIRST take note on ALL you change! You can compromise the TV ...

SOURCE: Samsung LN-R408D - No Picture

My Mom's LNR408D also had sound but no picture. I was able to fix it by soldering in a jumper wire across a blown (1.5A ???) SMD picofuse on the "T-Con" board.
Consider attempting this ONLY if you: 0) Know enough to avoid the potentially fatal High Voltage parts of the power supply board!!!
1) Are a fearless hackazoid 2) know what you're doing with a soldering iron and teensie SMD parts 3) are gonna throw the busted thing out anyway so you have nothing to lose and won't be sad if you screw something up.
4) Know enough to avoid the potentially FATAL High Voltage parts of the power supply board!!!!!


This board is at the top center under a close fitting RF shield. The suspect part was labeled "CP" on the board and marked with "P" on the part. It is visible above the right-center of the connector from the main board. An ohmmeter showed it as open, so I bypassed it with a jumper wire from connector VIN to the hot side of C13. One image shows the suspect part and the jumper in place.


The other shows the TCON board placement top-center (under its RF shield). With care, it seems possible to test the fuse and put the jumper in place without removing the shield. (Obviously don't touch anything else with the VOM leads!)

Thanks to ZORBUS and Steve's TV and Electronics for the idea.
http://www.avforums.com/forums/lcd-televisions/892447-no-picture-but-got-sound-my-samsung-lcd.html
http://www.gesda.com/transformer/Fall08_files/Page336.htm
Steve C

SOURCE: hi my samsung lcd tv model le40s8, it won't switch on

if you can do soldering work, replace two 1000uF10v bulging capacitor with 1000uF 16v or 25v in powersupply board. you will save $200.

SOURCE: Self- reboots at start-up, then shows picture but with pink dots.

Howdy,
It sounds like you have a Power Supply Board problem. The PSB is the center Board (towards left) after you remove the back off the TV. Remove Board from TV with the 6-7 screws. Replace capacitors CM811, CM812, CM817 & CS806; 1000ufd 25volts. It is the board to the left and you notice that the four cap tops are swollen.
It is easy to replace get a stanard solder pencil and you are in business.

Thanks for using FIXA, BIG IRISH.

Testimonial: "Thanks for the advice, guy. I already replaced the 2 that were swollen, and now my TV is awesome again. Will replace all caps if it happens again."

SOURCE: Samsung LNS2641D 26-Inch LCD HDTV lost its picture

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.