Bad capacitor? Monitor repair.

[redpoint5]

The Samsung LCD monitors at work tend to fail quite often (more than CRTs used to), and the warranty is running out on most. The most common problem is exhibited by the power LED flickering on and off, while the screen attempts to light. I was able to fix 1 monitor by replacing the power supply board with one scavenged from a dropped monitor.

I've got many more monitors with the same problem, and want to fix the broken component on the power supply board since I don't have any more good ones.

Does a slightly bulging end on an electrolytic capacitor indicate failure? Some even have a very faint amount of residue. I've attached some pictures of the capacitors in question, and would appreciate feedback. Note: one of the capacitors has no bulging.

[Moeyyy]

From everything I have personally seen, if the top of the cap is bulging, it has blown.

http://www.badcaps.net/pages.php?vid=5

This site has alot of information and may help you

[.DC.]

Quote from Moeyyy : From everything I have personally seen, if the top of the cap is bulging, it has blown. http://www.badcaps.net/pages.php?vid=5 This site has alot of information and may help you

Great Link!

[davepry]

Quote from redpoint5 : ... Does a slightly bulging end on an electrolytic capacitor indicate failure? Some even have a very faint amount of residue...

Yes, a bulging capacitor should be considered "bad". Even if it's only slightly bulging on the top, the bottom of the capacitor can also blow out, which is not apparrent until it is unsoldered from the board.

Replacing capacitors is not difficult to do, it just takes a little practice with a soldering wand. If you do replace the caps, I recommend replacing all capacitors of the same spec's, even if they appear good.

(What model of Samsung LCD's does your company have that are failing? I garbage-picked four Samsung model 214T's at work -- they all had blown cap's on the inverter board. I ordered replacement cap's from badcaps.net, and for ~$20 and a little bit of time, all four are working like new!)

[redpoint5]

Quote from davepry : (What model of Samsung LCD's does your company have that are failing? I garbage-picked four Samsung model 214T's at work -- they all had blown cap's on the inverter board. I ordered replacement cap's from badcaps.net, and for ~$20 and a little bit of time, all four are working like new!)

We have many different models. Currently I have a surplus of bad 740N 17" monitors. I wish I had known how easy these are to fix, as a dozen have probably been scrapped.

I'll pick up a bunch of caps from the local electronics store and make a habit of fixing these from now on. If my iron is already warmed up, I bet I can get get my repair time down to 15min each.

Edit: Caps I'm replacing are only rated at 25v, no need to worry about electrocution.
Thanks everyone!

[Raven1245]

Swap those bad boys out. I had this same problem. I swapped out two capacitors (50 cents each from the EE department, but radio shack had some for about $1.50 each), and it works alright now.

Look around though, because sometimes they go out because of another problem. But, they are an easy enough fix that you can swap them out first and go from there if there is any other problem.