Monday, September 12, 2011

Ressurecting the Dead (TV Edition)

So after hurricane Irene came through there were a series of bad thunderstorms that ripped through Maryland.  My mother-in-law's neighborhood was the unfortunate victim of a "well placed" lightning strike that killed her Vizio 32" plasma TV.  <rant>This is of course MY fault for not telling her that she needed to buy the EXPENSIVE surge protector</rant>  It wouldn't turn on, and the Vizio logo wouldn't light up (it normally lights up orange when plugged in but off, and white while actually powered up #powerleech).

Fearing the worst (and hoping for a free TV out of the deal), I took it home, painstakingly disassembled the outer case, CAREFULLY separated and set aside the outer glass (there's a tinted pane in front of the actual display that literally just sits inside the front frame, no screws or tape or glue, just little tabs molded into the plastic).  I guess that pane is to keep the heat away from the viewers?  Anyways, upon inspection of the circuit boards, I was surprised to see the LG logo everywhere, and also not surprised to see my old nemesis...

The BULGING CAPACITORS!


Those 5 with the crowned-tops are the culprits.  (They're also strangely arranged in a straight line...)

I carefully wrote down the positions, part numbers, values, and then de-soldered them one-by-one.  I give the designers credit for silk-screening the component numbers ON BOTH SIDES! (thumbs up) That is a HUGE help in trying to find the right sonnavabitch component to de-solder.

I had 2 replacements on-hand, and a RadioShack nearby.  Less than 24 hours later...


TADA!

<anecdote> Incidentally, a number of months back after a similar storm, I stumbled upon an LG 22" LCD widescreen monitor in the dumpster, which only had a minor scratch on it.  That particular model isn't in production anymore, but it sold for $230+ when new.  It would only show a white screen when I attempted to power it on, so it was in "better" shape than the Vizio but otherwise unresponsive (no menu, no text, just pure white).  After I opened it up, I saw the exact same problem, and oddly enough they used the exact same manufacturer of caps (although looking back that shouldn't surprise me if in the end they both had LG boards inside them #duh).  The problem I ran into with the monitor, though, is I got it working, but it showed the white screen after I put it all back together.  It pissed me off confused me at first, but then I realized, the connectors had been TAPED in place before I took it completely apart, and I removed that tape to fix the boards.  As I was reassembling, the connectors were falling out, because they didn't have really anything in the way of retainers.</anecdote>

Lesson learned:  make sure your connectors STAY PUT when you reassemble! #moralofthestory

<rant> Manufactures, in a misguided and mostly cost-minded fashion, tend to pick components that just barely go over the "expected" operating parameters of the circuit being designed.  Using more robust components costs money, so they use just what they have to.  Because of that, a simple spike on the power lines kills many electronics which end up in the dumpster and the landfill when they could EASILY have been saved by just using a few better quality components, and/or if someone bothered to open them up to fix simple issues like this.  What a shame... #ewaste</rant>

No comments:

Post a Comment