This Does Not Compute

Technology, gaming, music and things that just don't compute

Fixing a Completely Dead LG Refrigerator

blown-fuse

While heading out to work one day last week, I went to grab a cup of yogurt from the fridge to find that it was completely dead. No interior light, no control panel lights, no fan or compressor. This concerned me as our LG refrigerator is only about 5 years old (and was pretty expensive when we bought it, $1500). I had no time to diagnose the problem right away, but vowed to figure it out when I got home. Here’s how I revived my fridge and saved $350 in the process.

The fact that the fridge had no power whatsoever gave me a clue to start researching against. And indeed, a quick Google search with keywords like “LG refrigerator no power” led me to various forum posts from homeowners who had been in a similar situation. Most of them explained that they ultimately needed to have the fridge’s controller board replaced, at a cost of $250 plus labor of $100 or so. But after a little more searching I found a few folks who mentioned that the problem was due to a fuse.

As soon as I got into work I had called and scheduled an appointment with a repair company, in the chance that it was a problem I couldn’t fix myself (or required parts I couldn’t obtain on my own). They wanted $95 to diagnose the problem, but couldn’t be out until the next day. All of the food in my fridge would have gone bad by the next day, so as soon as I got out of work I hurried home to see if I could fix the problem myself.

To access the controller board (on my model of fridge, at least), you need to remove the cover panel on the back:

cover-panel

 

It’s just three sheet metal screws. Needless to say, you should unplug the fridge first.

controller-boardThe controller board runs everything in the fridge. It has three sections, as far as I can tell: an AC power input stage, a DC section with the ICs, and a DC-triggered AC relay section for triggering such things as the compressor and icemaker.

I disconnected all of the wire harnesses from the board and unclipped it from its standoffs to remove it. After a close inspection, I found this:

blown-fuseAh ha. A blown fuse indeed. And, after following the traces, it looks like this fuse is on the AC input stage, basically the first thing that power from the wall outlet hits when it enters the fridge.

I called the repair company up and canceled my appointment; I could fix this myself.

Based on the markings on the board and the fuse itself, I needed a replacement rated for 250V and 15A. Those fuses are pretty common, but what I rightly suspected would be a snag was that LG used a through-hole fuse — the kind with solder legs on each end — instead of a clip-in fuse. And indeed, after calling and driving around to various stores, nobody had the exact part I needed in stock. With my Dilly Bars threatening to melt in the freezer, it was time to get creative, at least for a temporary fix:

temporary-fuseI ended up soldering a couple pieces of wire to each end of a clip-in fuse I got from the hardware store, then used those as solder legs to tie to the board. This was more difficult than it sounds, as I had to sand off some of the coating on each end of the fuse to get the solder to stick (and indeed, you’ll notice that my solder joint there is still subpar). But I got it installed in the board, then carefully put the board back in the fridge, crossed my fingers, and plugged the fridge in. After a few clicks and whirrs, the compressor sprang to life. Success.

Not content to leave a hack like that in place, I hit up Digi-Key and ordered the correct, permanent replacement part. Two days later a package of four ceramic through-hole fuses made their way to my door and the board got taken out of the fridge again:

new-fuseMuch better. If it wasn’t for that other glass fuse to the right of it, you wouldn’t be able to tell that the new fuse wasn’t installed at the factory.

I also noticed something interesting on the right side of the board; it looks like a serial connector, based on the board’s markings. I wonder what protocol it uses, and what information is available over it.

serial-connection

 

 

 

 

 

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