Basic Electronic Repair – Part 3, by J.M.

(Continued from Part 2. This concludes the article.)

Repairing a device whose batteries have leaked isn’t difficult – you just have to be careful and take your time. I once cleaned up and repaired a $300 laser level that was thrown away at a construction site because the batteries leaked, and it’s proven incredibly useful over the years.

Techniques for repairing other types of physical damage will obviously depend on the specific types of damage. Cracked or broken plastic cases or parts can be repaired with glue (I like to use JB Plastic Weld), hot melt glue, crazy glue, heat or friction welding – Make Magazine has a good article on repairing plastic. Storing liquid glue long-term as part of your preps can be an iffy proposition as it tends to dry out, but I’ve experimented with vacuum sealing an unopened tube of JB Weld Plasticweld in a mylar bag, and two years later when I opened it it worked fine. Another skill that I’ve found occasionally useful when replacing plastic parts in devices is aluminum sand casting – you can easily cast lots of different parts to replace broken ones, and it’s something you can continue to do even in a long-term grid-down scenario.

Replacing parts like broken switches, buttons and connectors is slightly more difficult and will depend a lot on what kinds of spares you have available. As I mentioned I’ve deconstructed hundreds of electronic devices over the years, so I have a decent supply of spare parts. If you do need to stock up on some parts I highly recommend Electronics Goldmine, which sells surplus electronics parts for really good prices. They occasionally sell bundles of assorted switches, connectors, etc. that have supplied me with many critical parts over the years.

Hack-a-Day also has a good article that discusses sources for various electronic components. If you can’t find an exact match for the broken part you may be able to substitute a similar part – I had a small slide switch break on a device and I couldn’t find a direct replacement, so I slightly enlarged the existing opening using a file and attached a slightly bigger slide switch I had into the new opening and held it in place with hot melt glue.

One thing to keep in mind is that like any complex topic, electronics has it’s own language. Even something as simple as replacing a broken connector can turn into a task if you don’t know it’s ‘official’ name. There are some good introductions to various categories of physical electronics components available on the web – I recommend you review them and save copies for future reference:

• General connectors
• Ribbon cable connectors
• Power connectors
• Switches
• All connector types
• Mounts

One thing I always do when I have a device open is to check all of the connectors and mechanical parts. Ribbon connectors, power socket connectors, etc. are physical connections that rely on a mechanical or friction-based grip to retain the connection, and things like switches are mechanical and tend to break before anything else. I’ve spent hours trying to troubleshoot devices, only to discover that the problem was a loose connection or a broken switch.

More Power, Scotty!

If the device isn’t physically damaged, the next most common type of problems you’ll encounter tend to be related to power. Every small electronic device requires power to operate, which usually is provided by some form of battery. Batteries utilize a chemical process to store and release power, and a battery’s capability to store power degrades over time until eventually it can’t power the device. This can result in reduced or inconsistent operation of the device, or failure to even power up.

If the device uses standard replaceable batteries (e.g. AA/AAA/coin/9V/etc.), you should first check how much power the batteries are providing using your multimeter. Standard replaceable batteries are rated at something called ‘nominal’ voltage, which is the voltage they provide when fully charged and is what most manufacturers list as the voltage. Here’s a table that shows the typical nominal voltage for standard battery types and whether or not they’re rechargeable:

As batteries are used they discharge over time and their voltage drops. For example, a standard AA battery may start out at 1.5V, but after even a short period of use it may drop to 1.3V and stay they for a long time, even as it continues to discharge. Most electronics are designed to accommodate this voltage drop, but every device has a voltage ‘floor’, which is the lowest possible voltage it’s batteries can reach and still continue to function. Some devices will display a message, flash an LED or beep when the battery voltage gets too low, some will continue to try to run until the batteries are exhausted. The user manual for your device may include information on how it alerts on a low battery level. If the device won’t power on at all, try to remove the batteries and measure their voltage using your multimeter – if it’s significantly below the nominal try new or recharged batteries. Make sure you measure the voltage on the replacement batteries to verify they’re ‘full’ before putting them in!

Many modern electronic device come with a rechargeable Lithium battery instead of standard batteries. The vast majority of these are flat rectangular batteries designed to provide a nominal voltage of 3.7V. Some are designed to be replaceable by users while others are built into the device. Regardless of the type they’re subject to same limitations as standard batteries – they can only be recharged a certain number of times before they lose their ability to hold a charge. Lithium-based batteries tend to provide a longer life than other types of batteries, so they can last through thousands of charge/discharge cycles before degrading below what’s required to run the device. However, if you intend to rely on the device as part of your long-term survival preparations there are a few things to consider:

• Devices with Lithium batteries are typically recharged using some kind of cable connected to a power supply, which might plug into the device using USB, a barrel connector or some other type of connector. You should always make sure you have an extra charging cable for every device – I can’t tell you how many frustrating hours I’ve wasted trying to troubleshoot problems on a device, only to find out the problem was a bad cable!
• The same applies to the charging power supply – make sure you have multiple possible sources of charging power in case one dies.
• Whenever I acquire a device with a Lithium battery that that’s part of my preps I always buy a spare battery for it, since I know I’ll have to replace it eventually. I’ve stored replacement Lithium batteries for over two years and they still work as good as new when I installed them. If it’s a device I use fairly frequently I’ll swap the batteries every year or so. The industry recommendation is to charge Lithium batteries once a year, and to store them with around a 50% charge.
• If you don’t want to open up your device every year to swap the batteries, there are USB battery chargers designed to plug into and recharge your spare 3.7V Lithium batteries. The problem is going to be making sure you have the right type of connector, so you need to carefully measure your battery’s connector. A digital caliper is useful for fine measurement of connectors.
• If the device doesn’t seem to run as long as it used to that’s a good sign the battery is dying. Lithium batteries will typically slowly degrade over time, depending on the rate of usage and recharge frequency, then they’ll hit a point and drop off quickly. Something else you may notice is the device appearing to swell up – that’s a sure sign the battery is past it’s useful life and needs to be replaced before it ruptures.

Talk To Me

Something else that can be useful when troubleshooting electronic devices is information provided by the device itself. If the device has any kind of screen it’ll frequently provide error codes when something goes wrong. The same holds true for various LEDs – manufacturers will frequently set up different blinking or color codes to provide information about problems that may occur. The problem is that just like car manufacturers, device manufacturers don’t always provide information on what the error codes mean. You can check the user’s guide which may provide that information, or you do a web search for things like ‘model_name led codes’, ‘model_name led blinking blue’, or any other relevant condition you observe. Don’t forget to save anything useful you find in your local collection in case you run into the same problem in the future.

Where To, Next?

Being able to fix user, physical and power-related issues will enable you address a large percentage of the problems you’ll encounter with electronic devices. Going beyond that will require you invest in some additional study to learn slightly more advanced electronics repair techniques. Here are some references I recommend if you want to take your electronic repair skills to the next level:

• ‘How to Diagnose and Fix Everything Electronic, Second Edition’ by Michael Geier
• ‘Practical Troubleshooting of Electronic Circuits for Engineers and Technicians’, EIT training course (online course material)
• ‘Troubleshooting & Repairing Consumer Electronics Without a Schematic 3rd Edition’, by Homer L. Davidson

Conclusion

Many of us incorporate electronic devices into our preps and plan our survival activities to leverage these devices. Such devices can significantly extend your observation range, improve your safety, help you shoot, allow you to see in the dark, and give you instant access to an extensive range of critical information. While you hopefully have backup plans and capabilities available that can allow you to continue to function without the devices, having the ability to repair them can significantly extend their useful life and enable you to continue to leverage them.

Repairing the most common failure types for electronics isn’t difficult – it just requires some knowledge, basic tools and patience. Start practicing now to save money and start building a collection of spare parts, and you’ll be a lot better positioned when the grid goes away and you’re forced to fall back on your own resources and skills.