Samsung lcd bad cap problems

Hey guys, recently I scored a Samsung 943nw monitor from my friend who says it's broken. So i thought, why not try repair it? Upon opening the lcd monitor up, I can see that the caps were bulging, samwha brand. The infected caps were three 25v 820µF and two 10v 1000µF. I went and sourced the caps from a couple of devices (a modem, and a power supply) When I turned the lcd on, the led was blinking. After the repair(with my crappy soldering skills), the monitor turned on, but not the backlight. I figured that the cc backlight inverter was spoiled. Then, after a probing at the components, I reset the monitor in hopes that the inverter would work. Instead, now the monitor showed no signs of life. Probing again showed that the 5v rail was 8.45v and 15v rail was 4.5v and 3.3v was ov. I still can't find the problem after hours of searching. (and a fatal electrocution from the mains input cap). Could it be my bad soldering, parts or some transistor problem? DId I also accidentally fry the image processing module?

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There is no way its going to work with soldering like that. hard to tell from the photos but diode d102 looks like its got hot and could also be faulty.

You need to get a solder sucker, some good quality solder and also a decent soldering iron by the look of it, also have a look at some you tube clips on how to solder.

Good on you for having a go and you will find that most electronics can be brought back to life just by replacing the caps.

Phoenix Tech (author)  liquidhandwash1 year ago

(late reply) I too got a solder sucker but it's not too effective. I guess my cheap soldering iron was at fault(tip oxidized). To solve this problem, I am finding a cheap lcd controller board to use with it.

Looks like you obliterated the traces. Chances are the traces aren't even making contact with your solder joints in some places. afraid you may have torched this one. If you where applying enough to burn out the traces like that there is a good chance you could have damaged another component.

May be a good idea to go ahead and use this board for some desoldering practice. If your just heating the solder up and trying to pull the part or your using a deslodering braid your doing it wrong. Go out and get yourself a cheap pump. Or just remember to apply a liberal amount of flux to the braid before you place it on the joint and heat it up.

Phoenix Tech (author)  mpilchfamily1 year ago

Thanks for the suggestion. (sorry for lateness) Well, i think the problem with my soldering iron (60w chinese stuff) is that the tip is not hot enough to melt solder, but the neck of the soldering tip melts it, which caused me some difficulty in replacing the new caps. Anyway, I have decided to get a lcd controller board to get it working(at least)

tomatoskins2 years ago

Hmmmm... That's a difficult one. One thing I might check is the capacitors that you just installed. If something was wrong before that caused those capacitors to go bad it could still be wrong and killed your new ones.

I would also try a higher watt soldering iron. It would make for a better solder joint.