The Most Annoying Repair is the “Simple” One
In my line of work, I handle a lot of automation parts. Sometimes, surplus items pop up. I recently sold a tested, working Yaskawa Sigma-5 servo motor on a used parts forum. I confirmed it was working and shipped it, but a few days later, I got a message from the buyer: “It doesn’t work.”
I immediately issued a refund and got the motor back. I was genuinely curious about the cause of failure.
As soon as the motor arrived, I didn’t even need to hook it up to an amp or a tester to find the problem. A quick visual inspection was all it took.
Yep. One single bent encoder pin. This was almost certainly the culprit. And honestly, I felt a bit… deflated. This wasn’t a complex failure. It was just a “bent pin.” A trivial, annoying, and easily avoidable problem.
The Technician’s Dilemma: Why Tweezers and Pliers Fail
Now, “just straightening it” isn’t as simple as it sounds. These pins are incredibly thin, fragile, and packed densely together.
- Needle-nose pliers? Too big. You can’t get to the bent pin without damaging the surrounding ones.
- Thin tweezers? Maybe, but they lack the rigidity. They tend to slip, and you can’t apply controlled force to straighten the pin properly. You’re more likely to just kink it in another direction or break it off.
So, what’s the solution? A ferrule terminal.
The A-Grade Trick: Using a Ferrule as a Custom Tool
This is my go-to method. A ferrule (the little metal tube you crimp onto the end of stranded wire) is the perfect tool for this job.
- It’s hollow, allowing it to slide over the pin.
- It’s strong, providing 360-degree support to the fragile pin.
- It comes in various sizes, so you can find one that fits the pin diameter perfectly.
I just find a ferrule of a similar size, maybe give it the slightest crimp with my pliers so it’s a snug fit, and it becomes the ultimate pin-straightening jig.
⚠️ A Quick Warning: This is a delicate operation. Be gentle. If you use excessive force or get impatient, you will break the pin clean off. Attempt this at your own risk.
You just gently slide it over the pin and slowly, carefully bend it back to its original vertical position. Because the ferrule supports the entire pin shaft, the risk of kinking or breaking it is dramatically reduced.
The Result: Back in Business
It’s a manual, handcrafted repair, so it’s impossible to get it perfectly straight back to the factory-original state. But it’s more than good enough.
I tested the motor again, and of course, it worked flawlessly. The problem was solved. Now, this motor goes back into my warehouse.
The Real Fix: How to Prevent This Mishap
This whole incident was just a simple, unfortunate mishap. But it brings up a critical point. This kind of damage almost always happens for one reason: forcing the connector in at the wrong angle.
If you align the connector properly before you push, this will almost never happen (unless a pin was already bent). It seems trivial, but the basics are always the most important.
A little patience costs nothing. A new servo motor costs a fortune.
