Monitor backlight turning off when signal cable plugged in
I have recently bought a faulty Samsung Syncmaster F2380 monitor in hope of fixing it and using it for personal purposes. The device used to work for a few seconds before turning off the backlight until pressing the power button. After opening up the device I noticed one cable of the CCFL backlight had burnt at the solder point on the CCFL tube. After resoldering the connections to the tubes and checking everything else I reassembled the whole thing back together.
Unfortunately now the monitor turns its backlights off when plugging in a signal cable (e.g. VGA or DVI), but remains on when not plugging one in (except it outputs the expected "Check signal cable" because nothing is plugged it)
I have also checked all capacitors on the main power board, as the CCFL lamps connect directly to it. I do not know how to check whether the CCFL Lamps are working or where the issue lies, but its just strange that the backlights only turn off when plugging in a signal cable. I would get an image for a few seconds, then the backlights would turn off. Perhaps the device turns on additional backlight lamps when it receives a signal?
I will open it up again sometime, and check which lamps actually turn on or not when plugging in a signal cable.
I really dont know what things to check next, so I would really appreciate help on this topic (especially as many others are having this issue as well)
crwdns2934109:0crwdne2934109:0
crwdns2944067:02crwdne2944067:0
It seems to me that something is overloading, and that the backlight turning off is a symptom of a greater problem, faulty or burnt out capacitors somewhere perhaps.
I can see that there are two dvis and vga port on it, does this happen when a cable is plugged into ANY port? Does the BL turn off when a cable is plugged in to the monitor but not a device on the other end?
crwdns2934271:0crwdnd2934271:0 Conor Bailey crwdne2934271:0
I might try replacing most caps on the power board anyways for now.
The backlights dont turn off because of a short circuit when a cable is plugged in. Rather they only turn off when there is a video signal coming in from any of the ports. Only plugging in any video cable doesnt make them turn off.
I noticed that the device outputs the "Check signal cable" message with one set of backlight tubes unplugged, while with the other set unplugged the transformer makes a weird noise and doesnt output anything at all.
Actually, every time the CCFL lamps turn on the first time or when they go off the power boards transformer makes a little high pitched noise. With no video cable plugged in and while it is waiting for signal the backlights are on, and the transformer does not make this sound. Sadly I cannot find a replacement transformer anywhere though.
crwdns2934271:0crwdnd2934271:0 Daniel crwdne2934271:0