Fixing my LCD TV

[floodhound2]

Our TV would not function this afternoon and as always I took it apart to see if I could fix it. At first glance I took note of the power inverter for the backlighting and switching power supply. This seems to always be the issue with electronics mainly because its the work horse that takes a beating. Imagine thunder storms, transients and brownouts and your a switching PSU!

The cool thing about some electronics PCBs (if you get lucky) is that they have a nice silkscreen that you can use sort of like a road map. Frankly this made things much simpler. A few logical and wise test using only a volt meter uncovered the problem. The secondary winding's in a transformer that powers the back lighting was measuring as an open. The part is on order; soon ill have this TV back up and running.

Remember kids; work on electronics like TVs cautiously - cause there can be thousands of volts ready to bite you in an aggressive manor. especially in the power inverter section.

Stay tuned cause once the part is here ill demonstrate how to remove and re-solder it on.

Below, the opened TV (star trek door opening sound effect)


The dead inverter board


This is what a transformer looks like dead, well it looks sort of the same alive but my meter can tell. I measured its resistance and got infinite meaning open! Meaning broke so using a 10X I read the part number and ordered a new one. Total cost $6.00.

[DNR]

nice! I heard its not too hard to fix some of these TVs, due to their similar qualities to computer laptops and monitors


DNR

[computathug]

Nice one Floody, that surely saved you a few bucks on either a new TV

[Hiram]

Good work!
In electronics, from the power supply circuit, there is more complexity.
If the problem is not in the power circuit, the rest tends to become guesswork.
But the 'ATE' ( Automatic Test Equipment) simplifies work, expensive though.

[Lundis]

Do LCDs always have that many transformers? Is it to save space or something?

Speaking about TVs, I made a small TV I found in a trash container into a oscilloscope today. I still need a small amplifying circuit to make the waves more visible though. Soldering while knowing that there's power in the capacitor is always exciting. I even managed to damage/melt the edge of my multimeter probe when using it to short out a capacitor once xD

[floodhound2]

Lundis

Yeah bro get them hands dirty. I love it. A cap can zap as they say. My particular television (and many for that matter) do need transformers to bump up the voltage supply that feeds the back-lighting circuit. I did not measue it while I had the cavity open but I would not be suprised to see ~ 1K volts give or take a few K volts. Some of the newer TVs are employing a back-lighting technology that use an entirely different approach and with that obviously come a smaller package (chicks love small packages right?).

Now
To the pics of the completed job. Sorry I am posting this a tad bit late I am super busy with consulting work.

The part arrived, and the total cost ~ $11.00



Using solder wick I removed the old part. Nothing magic about it just lay solder wick over the pin that you want solder removed from and heat with soldering iron tip. Keep heating until the wick soaks up all the solder. If the solder wont flow make sure your soldering tip is clean.


Solder wick, clean tip and heat. Soaks it all up!


Part is extracted and left a little smudge behind. All that dark stuff is, well, flux and grime not a burn mark. No worries.


Testing old part for the hell of it. My meter reads infinite meaning an open in the transformer.


Drum roll, first attempt and...

... freaking cartoons wtf... Kids

Hope this was a fun read.