Few weeks ago, my sister-in-law asked me to fix her LCD monitor, which became dark, very dark when turned on. It's a 19" Westinghouse model L1975NW. I took the back off, and notice the board has few components which responsible to drive the back-light of an LCD screen. After tracing out the circuit, and identify failed components (a surface mounted fuse) I went ahead order parts at Mouser Electronics. Even though only the fuse is definitely failed, I also order new FET & capacitor, just because I have no way to test them. While waiting for the parts to arrive, I removed the FET, capacitor & the surface mounted fuse. Few days later the parts arrived, I soldered them on the board and very happy that the monitor is now fixed. If there are anyone interested, I'll post the part lists & locations of them on the board.
Here is the picture of the power board, with the FETs circled. Unfortunately, I did not take the picture of the other side, where the surface-mounted fuse resided. After removed these components & replaced with new ones, the monitor works again. BTW, when I order the FETs, I also ordered the clip on heat-sinks for them, I believe that these FETs were driven so hard & so with the heat sinks they will certainly help prolong the life of the new FETs.Here are the list of parts that I ordered:
Removal of the FETs was not that bad, but soldering the surface mounted fuse was a bit difficult. My eyes aren't as good as they used to be, so I need a magnify glass to perform this task.
Also, correction: I also ordered the capacitors, however I did not replace them, for I believed replacing the FETs & fuse would be sufficed, and indeed they do. So, after replaced the FETs & fuse, I put them back together and the monitor is revived.
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3 comments:
I have having the same issue and plan to repair it myself. Can you please post the locations of these items on the pcb.
Thanks.
Hello Mike,
Sorry for the late respond.
I've updated the blog to include the parts as well as the link to Mouser Electronics on each part. I also updated the picture to identify where each part is located. One thing that I forgot is to take picture is the other side of the PC board, where the surface mount fuse is located. So sorry.
Vương Quốc Anh (Ly),
Thank you very much. I tried replacing the fuse but think that I may have over estimated my ability to get my big fingers in such a small area. :)
I replaced the fuse but am not sure I did a good job. I ordered a couple of extra fuses and will order the FETs and heatsinks, and will try to replace all of them at once.
I have successfully located the fuse.
Thanks again.
Mike
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