👀 External Analysis
When beginning to tear down a device, you'll want to take in as much information as reasonable at each step of the process. Initially, this means taking pictures or notes of all of the stickers, seams, and interfaces of the device.
Good things to know about from the stickers:
- Power Inputs/Outputs
- Port Labels (especially if ambiguous)
- Button Labels or Descriptions
- How the case seams appeared before disassembly.
- Various Make/Model/Serial #/Mac/FCC-ID information.
Labels are a nice place to start your information gathering. Its not ground truth, but a good point to start anchoring characteristics of the device until otherwise proven incorrect or misleading. Many labels have a set of industry standard identification that can be used to get a deeper knowledge of a device that isn't always included in accompanying documentation (even when purchased retail).
Some standard identifications that can be further queried:
- RoHS - Restriction of Certain Hazardous Substances
- IC - Industry Canada, you can search for radio information via the Radio Equipment Search (Fill in the Certification Number with IC ID)
- FCC - US Federal Communications Commission
As an example of some information you can gather from a simple label, check out the Belkin Case Study where we start with only the label and work our way to more detailed information about the device including part numbers and a datasheet!
Port / Button / LED Labels
One thing I often forget is to jott down what each LED, button, or connecter is on the case. Once the case is off, the PCB usually doesn't have any indication of what the various things do. Knowing what each button or port is on a piece of adjacent paper, if not apparent, can be a big time saver.
Take pictures before and after when ever possible. If we break something in one device, we may want to prevent breaking the same piece on a similar device. Capturing these kinds of things in a photo is the easiest way to document not only what can be observed but how not to do something in the future.
If you don't have the ability to take a photograph, don't hesitate to draw and describe what you see. Identifying observations in a single place can be a life saver when you end up with dozens of parts all over the work space.
Tip: When taking pictures of really small or hard to see text on devices or components, I often find it helpful to snap the picture at different angles. Usually the various inks reflect light different than the surface its stuck to and will pop at certain angles.