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Backlight goes off after 2 sec on LG L1710S LCD monitor
Can see the backlight goes off after 2 sec , turning monitor off/on
or removing/ restoring video signal to monitor restores backlight for a short time before it go out again , I can see the display is working by placing a light directly on the monitor .
It is likly a faulty Inverter board , and i wish to repair the existing board , can any one provide assitance in its repair and testing for this model , I have knowlage of electronics.
have replaced lager higher voltage caps on Power board / inverter board of this unit and looked over the joints , with no change to date , can you specify which caps to change / review specific to the backlight issuehave replaced lager higher voltage caps on Power board / inverter board of this unit and looked over the joints , with no change to date , can you specify which caps to change / review specific to the backlight issue
removing the inverter board , i have replaced 1000uf 25v & 16v respectively electro caps ( 6 in total)
No bent pins or noticed dry joints seen in general or heated spots , resoldered main drive transistor and larger 1 watt resistors as per general rule , but with no change as yet in the result .removing the inverter board , i have replaced 1000uf 25v & 16v respectively electro caps ( 6 in total)
No bent pins or noticed dry joints seen in general or heated spots , resoldered main drive transistor and larger 1 watt resistors as per general rule , but with no change as yet in the result .
dont have a manual / cct diag for this monitor , can you advise the cap numbers id on the board that relate to the respective voltagesdont have a manual / cct diag for this monitor , can you advise the cap numbers id on the board that relate to the respective voltages
yes have done them and the voltage appears stable on both the 12 volt and 5v rails off the connector that goes to the logic board ,
i will continue to monitor/log both rails to see if there is a change over night ,yes have done them and the voltage appears stable on both the 12 volt and 5v rails off the connector that goes to the logic board ,
i will continue to monitor/log both rails to see if there is a change over night ,
dont know where the 3.3 volt rail are / caps related to them also what does the 3.3 volt do on the board out of interest ?dont know where the 3.3 volt rail are / caps related to them also what does the 3.3 volt do on the board out of interest ?
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Re: Backlight goes off after 2 sec on LG L1710S LCD...
I would suggest to open the monitor and check for a loose connection or cold/dry solder joint where the lights are connected to the inverter boards.
Let me know if you need more assistance.
Check page # 26 of the service manual for the list of capacitors that are connected to the 3.3, 5, and 12 volts line.Check page # 26 of the service manual for the list of capacitors that are connected to the 3.3, 5, and 12 volts line.
Their locations are C831, C832, C820 and C817. The ones I was more concern for dry conditions are the ones that filter the 5 and 12 volts but looks like you changed them already.Their locations are C831, C832, C820 and C817. The ones I was more concern for dry conditions are the ones that filter the 5 and 12 volts but looks like you changed them already.
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Sounds like a backlight problem to me. If you input a signal to the HDMI or Composite input and then it goes black have you tried taking a flashlight to the screen to see if the picture is still there but just dark? That would indicate a backlight issue. That model appears to be an LED edge lit backlight, so if the picture is still there after going black your going to have to trace out the backlight circuit and see whats going on. Usually with LED backlighting if it comes on at all then the LED's are good, its just the driver supply thats failing to keep them on. Some TV's have a small separate board that provides the backlight control, but i suspect with this model its on the power supply board and not the motherboard. Have you checked that board? It could be bad caps on the power supply board, check the voltages to the backlighting when it lights up and then when it goes dark. It could just be some failed capacitors on the power supply causing that voltage rail to drop off.
? 6:06
https://www.youtube.com/watch?v=BTjH-jkuo9Y
Jan 30, 2014 - Uploaded by Heilman Hackatronics
This videos shows how to repair an LCD monitor Backlight. ... I've Samsung SA300 21.5 inch led monitor ...
InstructablesHere are some simple instructions on how to replace a burnt out LCD backlight with a new working one to bring your LCD back to life. ... To get the the LCD screen and thebacklight inside, you must first disassemble the LCD housing; this is different depending on whether it is an ...
InstructablesFix any broken LCD backlight with an ordinary light bulb and a dead CRT monitor.Broken LCD monitors basically come in three categories:1) Cracked LCD ...
First, check the power supply for the backlight. It's usually a 24 volt supply. Look for swollen caps. If that is ok, go to the inverter board and inspect for damage, ohm out the inverter transformers. Last is to test out the lamps seperately with an external inverter. If a lamp goes out this way, it is bad and causing the whole backlight to go out.
my 12 power supply was only 500ma, not the 4a needed. Got the monitor to power up but now the screen goes dark after 2 sec. Looks like a bad backlight issue. I'll replace the inverter board.
Yes this is a back-light problem. The fault could be the inverter board which supplies high voltage to the CCFLlamp or it could be a faulty CCFL lamp, this lamp is a mini fluro tube.
For service, parts and DIY info check out LCD Parts - click on this link to their WEB site : - www.lcdparts.net
Most likely the 2 470uF capactitors in the power supply have leaked and partially shorted. If you have those replaced it should power up fine. The symptoms will be the green power light will come on and the backlight tubes will light up for about 1 sec then the entire monitor will shut off.
have replaced lager higher voltage caps on Power board / inverter board of this unit and looked over the joints , with no change to date , can you specify which caps to change / review specific to the backlight issue
removing the inverter board , i have replaced 1000uf 25v & 16v respectively electro caps ( 6 in total)
No bent pins or noticed dry joints seen in general or heated spots , resoldered main drive transistor and larger 1 watt resistors as per general rule , but with no change as yet in the result .
dont have a manual / cct diag for this monitor , can you advise the cap numbers id on the board that relate to the respective voltages
yes have done them and the voltage appears stable on both the 12 volt and 5v rails off the connector that goes to the logic board ,
i will continue to monitor/log both rails to see if there is a change over night ,
dont know where the 3.3 volt rail are / caps related to them also what does the 3.3 volt do on the board out of interest ?
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