Hi and welcome to the site,
Initially, postback with the brand and model number of the TV unit.
Offhand, one possibility to consider is low or missing voltage supply to the inverter from the power supply. If both the PSU and the inverter are on the same PCB (printed circuit board) and the inverter supply is present, then another possible cause is power management.
If you could postback with the model, then possibly the schematics or even the Service Manual (if available) could be posted.
Good luck and thank you for asking.
it is a 22" dell monitor. model # e228wfpc and yes there on the same board. no leaky caps or damage. looking for a used board or a fix. i have the tools. osilliscope , fluke meter and others. i am a parts changer but have good basic skills in daig. need help through it though. thanks
Have you tried checking / replacing C808 and/or temporarily replacing R821 with a lower value?
do you have a schematic for this model? i could re use it. just wondering why you asked about those c808 and that resistor?
Hi again,
Unfortunately, I don't have the exact schematics for a Dell E228WFPc. However:if the current PSU/Inverter combo is a 715G2594-1-4 which looks like this;
and C808 is a 2.2uF/16V capacitor while R808 is a 1M Ohm (105) resistor;
then it would be a variation of the Philips Hudson 8 chassis;
if yes, then the Service Manual (with schematics) is available here;
inverter schematics is on page 26;
modification is replacing R821 with 500K Ohms or placing a 1M Ohm resistor in parallel to C808.
Incidentally, a revised PSU/Inverter 715G2244-2 maybe viewed here. The mounting holes may just be slightly off.
MY BOARD IS A 7CH23A91 BUT LOOKS LIKE THE ONE YOU POSTED. I HAVE TO TAKE IT APART AGAIN BUT WILL TRY. DO YOU KNOW IF THEY ARE THEY SAME BEFORE I TAKE THEM APART? OR IF YOU CAN FIND THE SCHEMATIC?
I'm 99% sure at least on the models/versions available in my country.
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Do you still have sound? If yes then it is a backlight inverter failure. Note that it is not on the power board. Inverter board is a separate one and it will cost you around 50-75$. Component level repair is not possible as its full off solid state electronics.
Check out partstore.com
Does sound like the lights or the ballasts are failing which isn't too all that uncommon
What is the make and model of this tv?
it is a dell 22" monitor. model # e228wfp. the power supply and inverter board for lamps are on the same board.
That would be a power board problem. Usually due to bad capacitors. I would check to see if any are swelled up or you have burn marks on the circuit board. An analog tester would be helpful
already did. no leaky or bad caps. nor no other physical damage. looking for a used powersuplly board but can't find one. can you???
http://search.team1repair.com/?keycode=t...
tigerdirect.com
partstore.co.
http://compare.ebay.com/like/23049318178...
neither one of those links worked???
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Sounds like you know how to work on led tv's so; using a 'scope find the ballast protect transistor circuit that will not stay high or, use a multimeter to find the ballast protect transistor or, using component cooler freeze the ballast latching transistor per the schematic when it goes low and, drops the inverter output. failing all of that: post the power supply part# on ebay.com the inverter circuit is just the same as a florescent ballast in an office ceiling light as, are the CCFL or, cold cathode florescent lamps
actually just miniature office light fixture lamps If you do not have the schematic it is available online but, the schematics for the power supply is usually not included.
Hi,
I need model number and brand of your tv to provide you helpful info.
Thanks.
it is a dell 22" monitor model e228wfp...
Dell E228WFP
I'm afraid, no service manual/ schematics are available for above model to repair its power/inverter board on component level. However, find out inverter error signal pin and disconnect it for a while as this signal goes to system control that shuts off inverter circuit operation. Once inverter will turn On, it would be easy for you to locate problematic part, in my opinion, high voltage transformer that drives CCFL in back light can cause of such instant shut down.
OK, no problem.
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THANK YOU MAN. GREAT HELP. I WILL GET ON IT AND DO YOU KNOW IF I CAN ORDER FROM THAT SITE IF I CAN'T GET MINE GOING AGAIN? THEY HAD IT FOR 50 BUCKS?
it is a 7ch23a91
Benimur i ordered the psu/inverter board that i found and also a pack of 1m resistors and they got here today. so i installed the psu/inverter just now and have it running and will see what happens. but now want to fix the bad psu/inverter with the 1m ohm resistor in parallel with the c808. two things for some reason i can not view the post with the link to the schematic nor the reffence to c808 or the other resistor that could be changed to a 500 ohm if i didn't do the 1m on c808. also the boards part # i gave you first was wrong here is the correct # 715g2594-1-4.... witch you also posted on but cannot see any of that info you gave me. so if possible repost all that. thank you
Benimur i ordered the psu/inverter board that i found and also a pack of
1m resistors and they got here today. so i installed the psu/inverter
just now and have it running and will see what happens. but now want to
fix the bad psu/inverter with the 1m ohm resistor in parallel with the
c808. two things for some reason i can not view the post with the link
to the schematic nor the reffence to c808 or the other resistor that
could be changed to a 500 ohm if i didn't do the 1m on c808. also the
boards part # i gave you first was wrong here is the correct #
715g2594-1-4.... witch you also posted on but cannot see any of that
info you gave me. so if possible repost all that. thank you
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