Troubleshooting: Getting to the Source of the Problem


By Hylan Joseph

Troubleshooting is crucial to what we do as coffee technicians. Over the years, I’ve collected manuals and books about the best way to troubleshoot systems. This entry is a combination of several articles, training manuals, and other sources on troubleshooting that I’ve edited for training purposes. 

One of the most valuable—yet difficult-to-learn—skills for any technical person to have is the ability to troubleshoot a system. Troubleshooting is the act of pinpointing and correcting problems in any kind of system. For an auto mechanic, this means determining and fixing problems in cars based on the car's behavior. For a doctor, this means correctly diagnosing a patient's malady and prescribing a cure.

Troubleshooters must be able to determine the cause or causes of a problem simply by examining its effects. Rarely does the source of a problem directly present itself. Cause/effect relationships are often complex, even for seemingly simple systems, and often the proficient troubleshooter is regarded by others as something of a miracle-worker for their ability to quickly discern the root cause of a problem. While some people are gifted with a natural talent for troubleshooting, it is a skill that can be learned like any other.

A misbehaving system is still functioning to some degree, and may be stimulated and adjusted by the troubleshooter as part of the diagnostic procedure. In this sense, troubleshooting is a lot like scientific method: determining cause/effect relationships by means of live experimentation.

Questions to ask before proceeding:

  • Has the system ever worked before? If yes, has anything happened to it since then that could cause the problem?
  • Has this system proven itself to be prone to certain types of failure?
  • What are the safety concerns, before I start troubleshooting?
  • What are the process quality concerns, before I start troubleshooting (what can I do without causing interruptions in production)?

These preliminary questions are not trivial. Indeed, they are essential to expedient and safe troubleshooting. They are especially important when the system in question is large, dangerous, and/or expensive.

When first approaching a failed or otherwise misbehaving system, the new troubleshooter often doesn't know where to begin. The following strategies are not exhaustive or comprehensive by any means, but provide a simple checklist of questions to ask in order to start isolating the problem and serve as a starting point for the troubleshooting process. An essential part of expedient troubleshooting is probability assessment, and these tips help the troubleshooter determine which possible points of failure are more or less likely than others.

  • General troubleshooting tips
    • Prior occurrence
    • Recent alterations
    • Function vs. non-function
    • Hypothesize
  • Specific troubleshooting techniques
    • Swap identical components
    • Remove parallel components
    • Divide system into sections and test those sections
    • Simplify and rebuild
    • Trap a signal
  • Likely failures in proven systems
    • Operator error
    • Bad wire connections
    • Power supply problems
    • Active components
    • Passive components
  • Likely failures in unproven systems
    • Wiring problems
    • Power supply problems
    • Defective components
    • Improper system configuration
    • Design error

Good luck to you in all of your troubleshooting adventures!