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alaz11

@wnec.edu

sens 22" lcd tv with sound, no picture, white screen

So I've had my lcd tv for a year and a half and I hooked up the cable line at school and the sound works but the picture doesn't and it worked in May and the end of the school year last year. We have digital cable (if that note helps). I've tried different cables and cable outlets but nothing. I am also unable to see the DVD screen so I'm thinking it's the screen itself. It hasn't been dropped nor squished so I'm not sure what could have caused it.

S2201DVD is the model number, it was purchased from Circuit City in December of 2008.

Any suggestions on how to fix it?


TheMG
Premium
join:2007-09-04
Canada
kudos:3

First thing is to check the capacitors. They are responsible for a lot of TV/monitor problems.



Mdoc
Ehh... munch munch... what's up, Doc?
Premium
join:2007-03-27
Sterling, VA
kudos:1

1 edit

Yes, use an ESR meter (equivalent series resistance) to check the caps if you think you can do it yourself. Caps can be checked w/o removing from the board first, but you need to understand what you're looking at on the display.

»www.anatekcorp.com/blueesr.htm

edit: added hyperlink



android123

@anonymouse.org
reply to alaz11

to rule out the power supply, check the output. open monitor housing and look at the circuit board that the ac plug attaches to. the board should have printed on it the output values e.g. 12v and 5v. if the values are ok, than the power supply is ruled out. if values are not as specified, check the capacitors first.

how to check the caps?

1- visually - usually when capacitors go bad they look bloated or burnt looking. this will be obvious that the cap is bad.

2- analogue multimeter (cap needs to be removed from board... you can de-solder one leg of the cap) - set meter to 1ohm first then 10 ohms then 10 kilo ohms the thing looking for is to see the meter needle flick. if there's no flick, cap is open. no good. this method does not checl value though, only for opens.

3- use a capacitance meter (cap needs to be check off board). - this method checks for the value. e.g. 90uf. the meter does not have to read 90uf for a 90uf cap though, plus or minus 10uf is good.
4- ESR meter (can be checked with cap on board). you need a special meter to do this test. this test is more accurate cus it checks what the others tests can't - checks for cap leakage.

5- test cap under full load. this needs a special meter. needs to be checked with power applied.

the steps are listed from the most common to the rarest though.

there are more components that can give you a black screen though.

i'm not a professional though, take my advice with a grain of salt. i fix things as a hobby.



Mdoc
Ehh... munch munch... what's up, Doc?
Premium
join:2007-03-27
Sterling, VA
kudos:1

said by android123 :

- checks for cap leakage.

No -- resistance. A dried up cap will act like a resistor in series with a cap.


android123

@anonymouse.org

^ you are correct sir (ESR = Equivalent Series Resistance).

i confused step 5 with step 4.



Jason
Stowage Class Traveler
Premium,Mod
join:2001-01-24
38.2967 Lat
kudos:3
reply to alaz11

If you hit the menu button on the TV, can you see the menu? (when the TV is turned on, of course)

This will help you determine if the no-picture is a global power supply / display driver hardware problem, or a simple input problem..

-Jason
--
You can keep the change.



IllIlIlllIll
EliteData
Premium
join:2003-07-06
Hampton Bays, NY
kudos:7
reply to alaz11

white screen more than likely means a t-con pcb problem, not a power supply capacitor problem.
consider investing in a better major brand name for a tv, especially something without a built in dvd player.
most sets with a built in player will not operate at all if the dvd player fails or a disc gets stuck in it.
this was a relatively cheap set, my opinion would be to not waste effort and time attempting to fix it.
--



Mdoc
Ehh... munch munch... what's up, Doc?
Premium
join:2007-03-27
Sterling, VA
kudos:1

Oh, this is a TV, not a monitor. Sorry for the confusion. I no longer think it's necessarily likely a cap problem.