Category:Common Issues

Introduction
This article is a starting point that can and should be expanded an elaborated on. Please be aware there might be omissions or oversights, and not all instructions may apply to your specific issue or device. Before all, apply a generous amount of judgement.

General Advice

 * Try the easiest thing first.
 * Don't trust the other guy (the one who worked on it before you).
 * 90% of problems are human error or oversight.

Based on AvE troubleshooting 101 video, credit:

Formalized extended troubleshooting procedures
These “best practice” steps have proven themselves in many real world situations. The first steps are analytical and preventive actions that can (should...) always be taken, regardless of what the issue on hand is.


 * Document the case as presented by the client.
 * Research the failure and repair history of the equipment.
 * Analyze and document the current state of functionality as positives or negatives.

Now you have a dossier for the equipment that you can refer to for your technical analysis.

In order to troubleshoot safely, set up an environment that prevents error, overload or further damage.

Next, before you begin working on the device, do the following:


 * Disconnect the equipment from the mains power.
 * Place the equipment on an anti-static work area.
 * Disconnect any batteries.
 * Remove any storage.

This will minimize the risk of cumulative and/or collateral damage.

Once the equipment is well documented and secured, you can proceed to technical analysis of the issues.

Technical analysis
Start with a complete visual inspection. There may not be a singular fault: some defects are compound, involve multiple components, can be on both sides of a board, etc. A guide to Visual inspection of electronic components

Document your findings.
A simple sketch/diagram of where the visually-damaged components are is enough, and is useful further on in the process and to communicate with the client.

If visible defects are found, verify individual components and adjacent/connected components with electronic measurements to determine which ones are faulty and to what extent. A component may look bad, but be working fine, e.g. a connector that is slightly bent but is not otherwise compromised. If no visible defects are found, proceed to doing measurements on the electronics.

Continuity test
The most straightforward, easiest and most widely used measurement is the continuity test, which determines if a signal or current can travel freely between components. Failing continuity indicates if a component, connector or trace is broken. A continuity test can be done with something as simple as a battery and an LED (with the appropriate resistor).

Current flow test
Testing current flow requires testing equipment that can measure voltage, amperage, and/or resistance. In order to successfully test current flow you need to have a basic understanding of electrical components such as resistors, diodes, capacitors, transistors etc., and some idea of what is supposed to happen with the current inside the equipment. An original schematic is very useful for this, but wihout a schematic it is still possible to infer various functionalities based on the design of the device. Refer to electronic measurements guides, your test equipment documentation, and available schematics for operational details. If original, matching documentation and/or schematics are not available, it is possible to use “nearest neighbour” documentation, however be aware there are often significant differences between iterations of equipment.

Once a fault has been located, verified and isolated, the next step is the actual repair, which of course is a procedure in itself.