1. Home
  2. Electronics Repair
  3. Fixing a Maxent MX-26x3 LCD TV

Fixing a Maxent MX-26x3 LCD TV

I have a non-working Maxent MX26X3 LCD TV/monitor. Immediately upon powerup, it will generate anomalous vertical multi-colored lines throughout the entire screen with a blue background.

I've read about two known solutions, and I think both are related to one root cause. On FixYa, people have reported favorably changing the behavior of the TV by twisting a green heatsink that sits on top of a 208-pin QFP. That QFP is made by Trident, so I suspect it handles the video. One person used heat to reflow the pins.

There's a thread on badcaps.net featuring the MX-26x3 TV but nobody has posted successful repair by replacing the capacitors.

I'd like to try something similar to reflowing the pins. While I have access to a heat gun, I can't accurately gauge temperature. I also don't have a temperature marker. I think I would ruin the work with thermal shock from cooling down.

I was considering adding more solder to all 208-pins by flooding the pins with solder and using solder braid to remove excess solder and bridges, etc.

I'd love to get your thoughts on how to go forward with trying to repair this TV.

Thanks for reading.

Reply to
behindontaxes
Loading thread data ...

We used to solder fine smt parts like this sometimes by hand at the board shop I worked at years ago. One method was what they called "drag soldering", not to be confused with an actual drag soldering machine. We would use a fine soldering iron, and rosin core solder. As long as you are fast enough, and have enough flux present you can work from one end of the chip to the other, and just add solder to keep a small ball following the tip. This takes a lot of practice to master. Being that you only have one chip I wouldn't recommend trying it. The other way was to use a magnifying glass and a fine tip, with rosin core solder and tack each leg down. You only need a very tiny amount of solder. Mostly you just need the flux from the solder to get the old solder to wet. Try not to let the solder creep up the legs, it can be bad for the component.

Reply to
Sansui Samari

I've had excellent results from just appling a very small amount of liquid flux, then reflowing the existing crap solder with a small tip of a soldering iron (no excess solder on the tip, just tinned and nearly wiped clean/dry).

By a very small amount of liquid flux, I mean a small amount on the end of a wood toothpick, then dragged over a row of pins.

Working wih a magnifier lamp (or a magnifier lens with good lighting), it's easy to see when a thin line of flux is visible along a row of pins. With a magnifier and good vision, it should be clearly visible when the solder reflows, as each pin is individually touched with the iron tip.

If the heatsink is exending out over the pins, it won't be as easy, but probably not too difficult to accomplish with some patience and persistence.

-- Cheers, WB .............

Reply to
Wild_Bill

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.