The Unauthorized Guide to iPhone, iPad, and iPod Repair (2013)

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Repair Advice

You might have the following question: “Given that so much of the iDevice functionality hinges on the logic board, how can I test to verify that a logic board is, indeed, bad?”

The answer to that question is straightforward: Pull the suspected bad logic board from the source device and install it in a known-good device.

Remember that if you want to become a productive iDevice tech, you need to make a substantial investment for tools and parts. Some of these “parts” can be considered known-good iDevices that you can use for diagnostics such as these.

If you put a suspected bad logic board into a known-good iDevice and that device fails to boot then you can state conclusively that you need to replace the logic board on the ailing device. The same “swap” rule applies to the Dock Connector for iDevices that allow the Dock connector to be separated from the logic board.

Speaking of Dock connectors, let me provide you with a “cheat sheet” that you can use to instantly determine whether the connector can be replaced on an iDevice independently of the logic board.

TABLE 17.2 Relationship of Dock Connector to the Logic Board on Select iDevices

In my experience, replacing an iDevice logic board is a pretty straightforward operation. The only tough spots are the soldering requirement for certain iDevices, and the difficulty in removing the display assembly on iPads.

Overall, the best advice I can give you for sourcing replacement logic boards is to obtain a vendor referral from a trusted source. For instance, in a recent eBay auction search for an iPhone 4S logic board I obtained results that were priced from $13.50 to more than $200. That price variance is suspect, to say the least.

If you want or need to perform advanced diagnostics on iDevice Dock connectors and logic boards, then you need to use a multimeter. A multimeter is a hardware testing device that measures several electrical properties, including

Resistance

Voltage

Current

Theoretically, you should be able to use any ol’ multimeter to test iDevice electrical components. However, the good folks at Red Fish Instruments (http://redfishinstruments.com) have developed an iDevice-specific multimeter called the iDVM Multimeter. Figure 17.6 shows you this product.

FIGURE 17.6 The Red Fish Instruments iDVM Multimeter.

The iDVM is a combination of hardware and software. The iDVM hardware instrument communicates with your iDevice wirelessly, and reports its data findings to an associated iOS app. Pretty cool, huh?

Tips and Tricks for Logic Board Replacements

Let’s conclude this chapter with some targeted advice concerning things you should watch out for when you attempt a logic board replacement on recent iPhones, iPads, and iPods.

iPhone 5

iPhone 5 (and iPhone 4/4S, for that matter) logic boards are the easiest logic boards to replace in any iOS device. Sure, you have to field-strip the iDevice practically to the bare metal. You also have to remove a large number of microscopic screws. However, you have no glue or solder joints impeding your progress—in iDevice repair, that is a good thing.

The best advice I can give you for iPhone 5 logic board repairs are as follows:

Take all the time you need in re-seating the logic board. We know by now that Apple engineers make use of every square centimeter inside an iPhone chassis. Leaving the logic board the tiniest bit askew—which is to say, not 100 percent flush—will wreak havoc later on in the reassembly, particularly with the display alignment.

Be respectful of the interconnect cables and camera connections. Don’t just yank up the logic board from the frame during disassembly in an (understandable) moment of frustration. The interconnect cables are there for a reason, and these connectors, as well as those for the rear-facing camera, need to be seated properly during reassembly to ensure the iDevice will work properly post-reassembly.

I show you the relationship between the iPhone 5 logic board and the interconnect cables in Figure 17.7.

FIGURE 17.7 Treat the rear-facing camera and interconnect cables and connectors with care during a logic board replacement. (Courtesy of ifixit.com.)

iPad 3rd and 4th Generation

Logic board replacements on the 3rd and 4th generation iPads are extraordinarily difficult. As we’ve discussed previously, removing the glass panel/digitizer assembly runs a high risk of shattering the glass.

The best advice I can offer you, besides carefully noting which screws and connectors go with which components, is to stock up on Kapton tape. As you can see in Figure 17.8, Apple uses a copious amount of Kapton tape and adhesive to secure cables and connectors to the logic board and rear case.

FIGURE 17.8 iPad logic boards are secured with plenty of Kapton tape and adhesive glue. (Photo courtesy of ifixit.com.)

iPad mini

All of the standard precautions that apply to the full-sized iPads apply in turn to the iPad mini. With the mini, however, I advise you to remember that the Lightning connector is soldered to the logic board. This is shown in Figure 17.9.

FIGURE 17.9 In the iPad mini, the Lightning connector is soldered to the logic board.

iPod touch 5th Generation

In the iPod touch 5th generation, the logic board, battery, front-facing camera, Lightning connector, speaker, headphone jack, and Home button are all soldered together into an individual assembly. Fun, fun!

Therefore, the biggest disappointment in replacing the logic board on the iPod touch is that you can either:

Buy a replacement logic board assembly, with all connected hardware.

Use your soldering equipment to desolder and resolder the existing hardware components to the new logic board.

Figure 17.10 shows the removal of the iPod touch 5th generation logic board assembly.

FIGURE 17.10 Several components are soldered to the iPod touch logic board. (Photo courtesy of ifixit.com.)