Background (feel free to skip this part): A few years ago my first HDTV, this 42" Magnavox, started to have sound problems. I would have to turn it off/on many times for it to get sound with the picture to work and finally one day it would not turn on at all. So I took the behemoth off the wall and down to my local professional TV repair guy. He called me the next day and said it needed new "caps" and if I remember it cost me about $250... Keep in mind this was several years ago. I knew nothing about bad caps and didn't have any equipment or the know how to do my own repairs. He gave me a 30 day warranty on the repair. Any guesses on how long the repair lasted?... it failed around 65 day mark. I was pissed to say the least. However at the time I had other issues to deal with so I just took it back off the wall and sat it in the closet. I found a new 47" at Sam's Club for $500 and that was that.
Fast forward to this weekend when all of my tools and parts finally arrived so I could repair three old Samsung 204B monitors. They are heavy but 4:3 ration monitors are virtually non-existent now and I really like them. With $14 worth of new caps I was able to fix all three in an hour or so. One had other issues but the other two were fixed and back to perfect working order.
I felt confident in my new skill of soldering and caps repair and suddenly I noticed that old 42" LCD in the closet and I pulled it out and removed the PSU, as that was what I was told last time was the issue.
Problem: The current PSU is 715T2432 (if that helps) and it looks like the professional tv repair guy replaced the 3 caps at the top and possibly the 450v one on the bottom left. Also the center right yellow thing (rectifier?) looks to have been repaired or replaced. The solder joints on it don't look consistent IMHO. When I last plugged this in about a year ago it was blowing the fuse.
However when I tried to remove it I destroyed the fuse and have no idea what it was or what I need to buy to replace it. I do know that it was blown. And from reading other posts about similar power supplies the suggestion is not to replace the fuse until you isolate the problem and repair it. Another suggestion is bad diodes. I've looked it over and don't see any brown or heat spots around any of the little black diodes but I have no other idea how to test them.
I will gladly plug in a power cord and read any voltages but that 450v capacitor scares the crap out of me. I have a decent INNOVA 3320 DMM to use (and I just spotted a diode test icon!). I'm assuming you test those diodes without power but again I'm completely new to diagnosing electronics.
The attached photos are of my workbench and the faulty PSU front and back.
Any help is appreciated and I hope to learn as much as possible from making this repair myself, if that is possible.
Fast forward to this weekend when all of my tools and parts finally arrived so I could repair three old Samsung 204B monitors. They are heavy but 4:3 ration monitors are virtually non-existent now and I really like them. With $14 worth of new caps I was able to fix all three in an hour or so. One had other issues but the other two were fixed and back to perfect working order.
I felt confident in my new skill of soldering and caps repair and suddenly I noticed that old 42" LCD in the closet and I pulled it out and removed the PSU, as that was what I was told last time was the issue.
Problem: The current PSU is 715T2432 (if that helps) and it looks like the professional tv repair guy replaced the 3 caps at the top and possibly the 450v one on the bottom left. Also the center right yellow thing (rectifier?) looks to have been repaired or replaced. The solder joints on it don't look consistent IMHO. When I last plugged this in about a year ago it was blowing the fuse.
However when I tried to remove it I destroyed the fuse and have no idea what it was or what I need to buy to replace it. I do know that it was blown. And from reading other posts about similar power supplies the suggestion is not to replace the fuse until you isolate the problem and repair it. Another suggestion is bad diodes. I've looked it over and don't see any brown or heat spots around any of the little black diodes but I have no other idea how to test them.
I will gladly plug in a power cord and read any voltages but that 450v capacitor scares the crap out of me. I have a decent INNOVA 3320 DMM to use (and I just spotted a diode test icon!). I'm assuming you test those diodes without power but again I'm completely new to diagnosing electronics.
The attached photos are of my workbench and the faulty PSU front and back.
Any help is appreciated and I hope to learn as much as possible from making this repair myself, if that is possible.
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