Fault Finding on FST Life

7 posts tagged Fault Finding. Read the guide: Industrial Electrical Diagnostics.

• 

  Neal Wareing

  Field service technician and founder, FindFST

  30 Dec 2026

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  Looks fine. No comms.

  Profinet plug was in the right port, nothing obviously wrong. But the machine wasn't talking. Then look closer and you can see the profinet plug isn't properly closed. The fix isn't pretty. Pipe grips, steady pressure, make sure every pin is actually biting into the conductor. Caveman engineering. But it works. The temptation is always to replace the cable and move on. Takes longer, costs more, and half the time the new one has the same problem if you don't know what you're looking for. A proper crimp tool and a decent RJ45 plug would have avoided all of it.

  

  • Field Service
  • Fault Finding
  • Industrial Maintenance
• 

  Neal Wareing

  Field service technician and founder, FindFST

  3 Dec 2026

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  Terminals installed directly under a fan

  Multiple signals dropping out, no obvious cause. Pulled the covers and found it straight away. Dust being blown directly into the terminals, constantly. Every time that fan runs, it's packing debris into the connections. Not a fault with the signals. Not a fault with the wiring. A fault with where someone decided to put the terminals in the first place. Common sense isn't always common. The fix for the signals was straightforward. Getting someone to relocate those terminals properly is the actual job.

  

  • Field Service
  • Fault Finding
  • Industrial Maintenance
• 

  Neal Wareing

  Field service technician and founder, FindFST

  25 Oct 2026

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  Rookie mistake that cost me a full day

  First time I installed new cables, I did it as fast as possible. Get to the cabinet and all the plugs were damaged, cannot connect them. Spent the remainder of the day fiddling with a screw drive trying to re form the plugs. Spend an extra 10 minutes wrapping the sub-D plugs properly before running new cables. Save yourself hours of messing around trying to re form the plug later. It's a mistake you make once but a sure way to tell if someone is experienced

  

  • Field Service
  • Industrial Maintenance
  • Fault Finding
• 

  Neal Wareing

  Field service technician and founder, FindFST

  24 Oct 2026

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  More often than I can count, the long journey has ended with a straightforward fix.

  This was one of them. Intermittent faults are the ones that get your brain working. No pattern, no error code, machine runs fine for days then stops without warning. Power cycle, back to normal. Repeat. When someone says it happens randomly, that's the signal to look harder, not accept it. Attention to detail is what separates a proper diagnosis from a parts swap and a prayer. The photo says it all. Screws too long, plug not properly secured. The slightest vibration or movement interrupts the connection. Machine stops, customer power cycles, runs fine for another few days. Meanwhile the waste from every unplanned stop is quietly adding up. The fix took minutes. Finding it was the job.

  

  • Intermittent faults
  • Fault finding
  • Power cycle
  • Field service technician
• 

  Neal Wareing

  Field service technician and founder, FindFST

  1 Oct 2026

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  Commissioning an upgrade, EPROMs had just been changed. Power up, software errors, board not initialising.

  At first glance everything looks correct. Look closely and there's a bent pin not making contact. Hours can go into faults like this. Knowing what's changed in the past few weeks is a godsend when it comes to narrowing it down.

  

  • Commissioning
  • EPROM
  • Fault finding
  • Machine upgrade
• 

  Neal Wareing

  Field service technician and founder, FindFST

  27 Aug 2026

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  Machine down repeatedly, cause unknown. Current solution: power off and on.

  The signal kept dropping. No pattern, no error code. The machine would run fine for hours, then stop "randomly". Nothing is random. The cause is in the photo on the left. Wire insulation was clamped under the screw instead of the copper. Sometimes the strands made contact. Sometimes they didn't. On the right is how it should look. Crimped, correct strip length, nothing under the screw but copper. A hard fault costs you an hour. An intermittent one can cost weeks, because everyone starts by suspecting the expensive parts first. That is the real price of a shortcut during installation. Finding the right Field Service Technician can be priceless.

  

  • Intermittent faults
  • Wiring termination
  • Fault finding
  • Field service technician
• 

  Neal Wareing

  Field service technician and founder, FindFST

  13 Aug 2026

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  Emergency stop, machine down all because of one bad termination.

  I had a hunch it was an Arcnet connection. Found this. Insulation tape, broken solder, shield not even connected. Full cut and re-terminate, proper job. My soldering skills are a bit rusty, but when the machine is down you do what you have to, even it it means holding the solder with your teeth. One surprise, the sub-D plug is plastic. No obvious way to ground the shield. I'll need to get creative on that. And for the record, I'm very glad Arcnet is history.

  

  • Arcnet
  • Cable termination
  • Shielding
  • Emergency stop
  • Fault finding