We all have that friend who brings us their sad busted electronics. In [Leo’s] case, he had a MIDI sequencer from a musician friend. It had a dead display and the manufacturer advised that a driver IC was probably bad, even sending a replacement surface mount part.
[Leo] wasn’t convinced though. He knew that people were always pushing on the switches that were mounted on the board and he speculated that it might just be a bad solder joint. As you can see in the video below, that didn’t prove out.
The next step was to fire up a hot air gun. Instead of removing the chip, he wanted to reflow the solder anyway. He was a little worried about melting the 7-segment LEDs so he built a little foil shield to protect it. That didn’t get things working, either.
Using the same hot air gun he removed the IC and then used a contact iron to clean the pads up. We couldn’t tell if he soaked his wick in flux. That always seems to help get clean wick to soak up solder better. For the soldering job, he used a smaller contact iron and very thin solder. Of course, with the hot air, he could have used paste, too.
The replaced chip looked good. Did it work? Watch the video and you’ll find out. If you like this kind of repair porn, we’ve covered a lot of interesting fixes. Check out the massive power supply repair, for example. Or the cleanup after a computer took a bath in battery guts.