Question about a tricky TV power board repair

I was working on a Samsung UN55RU7100 in my shop yesterday, and the main fuse blew right after I replaced a bad capacitor. I traced it back to a shorted MOSFET on the primary side I had missed. Has anyone else run into this specific failure chain on these models?

3 comments

3 Comments

the_david21d ago

Sounds like a pretty standard power supply repair to me. That fuse blowing just means it did its job. Finding a shorted mosfet after a cap replacement is just part of the process, not some special failure chain. Seen it a hundred times on all sorts of boards, not just that Samsung model. Fix the short, replace the fuse, and it will probably be fine.

emmas1921d ago

Actually, that fuse blowing often means something else failed first (like the mosfet shorting). Just replacing the fuse without finding the root cause might make it blow again.

alice_grant21d ago

My first time fixing a power supply, I replaced the fuse three times before I realized the short was still there. I felt so smart after the second replacement, like I'd cracked the code. Then it just popped again and I had to face the music. You ever spend an hour fixing the wrong thing?