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  • Writer's pictureJohn O'Rangers

LRUs And Why Your Smartphone Manufacturer Likely Won't Repair Your Device

One of the hidden blessings of running this shop is where it is located. CDC is within the Washington, DC MSA, and with that, our customer base is very helpful. A lot of the people that frequent this shop are engineers, doctors, and scientists, and with that I learn from them as much as they learn from me.

I am no expert in anything. I regard myself as strictly a student, and with that mindset the learning never ends. Within the last day or so I was taught by a well educated customer some things that I can say I only understood on the periphery at best, but for the most part knew nothing about. Since his visit, I have been reading up on the concept and thought I'd share a bit of what I've learned with everyone, as it appears much of it applies to your smartphone repairs. Of particular interest is how a manufacturer repairs things like a smartphone or any electronic device, when they will do it, and to what level they will repair it. This is really important to understand.

Let me be straight and to the point before giving my infamous long winded examples. That way if you don't feel like reading everything I have to say, you'll at least have the most important information in your arsenal. So without further delay, why does your smartphone manufacturer often have very challenging repair policies? From what I've studied, it seems to come down to this concept of "LRUs". It's a common practice in manufacturer level support of products, and for the most part it is a sound concept. It's part of industry best practices, and it applies to many products, including your smartphone.

What is an LRU? It means "Line Replaceable Unit". Alternatively, the term "Lowest Replaceable Component" is used as well, and for the most part they mean the same thing. Simply put, a manufacturer reworks an electronic component in a certain manner, and they determine through a variety of metrics how deep in the weeds they are willing to go. So to make things simple to understand, a manufacturer designs a product and has exact specifications as to how it is supposed to work. When the product breaks down, their process is to repair it in a manner that restores the product back to its exact specifications and performance. No less, no more.

So this "lowest replaceable component" situation is determined by the manufacturer when they design and build a product. So let's take a circuit board for example. Let's say that circuit board gets water damaged, and some components go bad. The manufacturer has specific repair guidelines for dealing with this. Often times they'll simply replace the circuit board with a new one that is 100% spec. Could they replace the specific bad components on the existing board? Yes, but often in situations like that you'll find it isn't that straightforward. There could be deeper damages to address, there's time and labor involved, and often the repair might not be as reliable as a new board. Manufacturers do not have a tolerance level for this. They have a reputation and many times significant liability to their customers when it comes to the reliability of their products. Additionally, there are supply chain issues to consider. Reworking a circuit board is best left to dedicated individuals who do that, not a line technician in the field.

So simply put, they develop repair procedures that ensure the highest quality while being as efficient as possible. And there reaches a point where repairing existing components can get too deep in the weeds to meet this expectation. So in the water damaged circuit board example, yeah perhaps soldering in some new capacitors will do the trick, but replacing the entire assembly is quicker and often more reliable. Is it more expensive? Quite often it is, but remember, a manufacturer is in the business of meeting specs, not in cutting corners and creating workarounds for problems. That's not what they do, it's that simple.

At this point, if you wish to stop reading, I am confident you know where I'm going with this. But for those who wish to see some real-life examples I've encountered, please read on. I've had many experiences here at lowly CDC that have demonstrated clearly where LRUs matter. In fact, I've gotten myself in trouble a few times and had to swim my way out of it. I've learned the hard way, and believe me it isn't fun.

The best example I can give you, and it's an excellent one, is cracked display repair. With Apple, it's straightforward. You buy refurbished or new units and install them. The old ones get sold back to refurbishing companies where they're used to produce more replacement parts. That's a classic case of LRUs in action. No, I'm not fixing the broken display that's on the phone. I'm replacing it with a new one. That is the most efficient, reliable, and cost effective way to do it for both myself and you. Trying to repair the existing display is a whole other level reserved for larger refurbishing companies. I'm a repair depot, and as a repair depot my job is to fix the device as quickly as possible and do so to spec. Or at least as close as I can get it. Cannot do it efficiently trying to fix the existing display.

You with me so far? Good. The "lowest replaceable component" is the entire display, not the subcomponents of the display. It doesn't work that way. Now the question is, have I ever attempted to go below LRU and fix something in a manner outside what the manufacturer wants to do? Oh yes indeedy!! Many times, and oh boy did I learn some things. In some cases I've saved devices by repairing them out of spec, which the customers understood, but it got the job done. Water damaged phones are an example of this. In this business you don't repair water damage. You do whatever you have to do to get the thing to work enough to retrieve data. Beyond that I don't guarantee anything. I always tell a customer to get a new device. If they don't, that's on them.

But let's stay with the display repair example, as that's the easiest to understand. A few years back, the big egos in this business were pushing cracked glass repair on Samsung devices. I got into this despite my better judgement, and oh did I have a time with it. Was I successful? For the most part I was, but not always, and this taught me why these LRUs exist in the first place. Thankfully that process is all but dead nowadays, and hopefully it never comes back.

So here was the situation. Samsungs have long been known for OLED displays. Many times they continue working despite the cracked lens. So the average consumer goes on Amazon and sees a $4 aftermarket reproduction glass lens, tries to fix it themselves, and the results are predictably a disaster. So they'd come to me to do it. Often times they'd have no understanding of how these displays are built, and expect to pay maybe $50-75 for to do it. OK, sounds great, right? Not so fast! The entire display costs $175-$225 to buy, is brittle as all can be, yet I'm supposed to work for $50-$75? That was the first problem right there, and I should have trusted my instincts on this. But i let my ego get in the way.

The reality with refurbishing an OLED display is much more complicated than a piece of glass. Often the OLED itself has burn in, and isn't up to spec anymore. Uh huh, see where we're going? On top of that, the broken glass is glued to the OLED/Touch with a special optical adhesive. It's a liquid based adhesive, not the most environmentally friendly stuff, and it's cured with UV light. So you had to somehow get this piece of glass peeled off the wafer thin OLED without ruining it, and glue a new one down with optical adhesive. That was the only way to get anywhere near spec. There were some rogue shops out there that didn't do this and would simply tape the glass to the frame around the edges. Not spec, and unsafe as well. The touch wouldn't function well, and when that glass inevitably shattered, the customer would have razor sharp shards of glass in their pocket. Bad news!!

So gluing it was the only way. But this opened up a whole other can of worms. Sometimes the display didn't cooperate and it would crack. Other times heat would ruin it. The bottom line was that I had many many successful repairs, but a few that weren't. And guess what? The customer wanted the repair ASAP and would not accept any responsibility for the OLED going south. Their view? "It worked before, now it doesn't, so you have to pay for it". Now your $75 profit is a $100 plus loss. Yet if I just skipped all of that, charged $275 for a new display, none of these problems would have come up and my liability would have been reduced to near zero. Sounds mean like that dastardly Apple, right? That's reality unfortunately, and Apple understands this. They are not stupid people over there in Cupertino!

Compounding this problem were the successes. The customers often gained a skewed impression of the repair process. So they continued on with their behavior that resulted in the crack in the first place. When it happened again, they'd come by and expect you to do it again. But there was a problem. I found that a glass only job was good for one shot. Second time around? No dice in most cases. They were not happy, that much I can tell you, and it created a less than ideal relationship with that said customer. Bottom line? Bad business model; I should have never gotten involved in it in the first place. My fault.

Now do you see why someone like Apple or Samsung does what they do? They are not in the business of "making" things work. Things must work, and work as intended. And considering their customers have a level of expectation that comes with it, the LRU is what makes that happen. I learned this myself with Samsung glass repair. And to further prove what I learned was reality, guess what? Samsung told me so. I spoke with them at a trade show a few years back. Their reps were very aware of us independents doing these repairs and they were very clear with me. "We do not support or endorse the practice". They further added that Samsung repairs broken displays with a new unit, period. There's your LRU in action right there.

So to conclude, what does all this mean? Simply put, the gap between independent repair shops and companies like Apple and Samsung are not, in my opinion, the result of Apple being mean. It is likely due to LRUs. Independents often work outside the LRU, and that is not consistent with what the manufacturer does. Is the work of an independent bad? No, not at all, and it has its purpose. But when it comes to repair of your device, it's probably not as simple as what advocates like the "Right to Repair" movement claims. There's way more involved. So it's important that independents like CDC understand all of this, and do their best to repair devices consistent with what the manufacturer's best practices are.

I know this from learning the hard way.

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