I got a new Testec TT-LF312 probe for my oscilloscope and I noticed that on the probe's BNC connector, the pin in the center is bent sideways a little bit.

The result is that it takes a little bit more force than I'd expect to insert the probe and there's a good connection even when the BNC connector hasn't been twisted in the receptacle.

So is this normal manufacturing practice or a manufacturing defect?

UPDATE: Here's the photo. On the left, I have old probe and on the right I have new probe.

enter image description here

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    \$\begingroup\$ Can you post a picture? Incidentally, Having a good connection before the bayonet lock is twisted is common. Also, Where is the friction in the mating process? A good (new) BNC connector will normally be a bit stiff, as the metal fingers in the connector wear in. \$\endgroup\$ – Connor Wolf Feb 3 '13 at 10:09
  • \$\begingroup\$ I'd love to see an image. My gut feeling says it is bad for the connector at scope side and if there is one thing you don't want, it is breaking a connector on your oscilloscope. BNC-connectors are usually produced to pretty accurate specifications (due to their RF-nature). \$\endgroup\$ – jippie Feb 3 '13 at 10:22
  • \$\begingroup\$ @Fake Name Well the scope is 6 months old and the socket had less than 100 insertions on it. The probes that came with the scope connect with no force needed. I'll try to post some pictures, but I'm having problems taking a good photo. \$\endgroup\$ – AndrejaKo Feb 3 '13 at 10:22
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    \$\begingroup\$ It doesn't look all that bent in the picture. The pin is supposed to be centered. If not, just bend it back. However, do so gently since these pins are often made from rather brittle metal that is not intended to be bent. There are special tools for bending back pins of BNC connectors. Look for something called a screwdriver in a hardware store. \$\endgroup\$ – Olin Lathrop Feb 3 '13 at 16:35
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    \$\begingroup\$ @Olin Lathrop I'm afraid that here no hardware stores have such a specialized tool in stock. Most of the people I've talked to had to import them from abroad or make do with a simpler tool. Ah well, such is life. :) \$\endgroup\$ – AndrejaKo Feb 3 '13 at 18:03

Not usual and not part of the connector standard I'd say. But acceptable if it does not actually foul.

Straightening the pin (which should not be necessary in new equipment) would be likely to be safe for a careful competent user doing things with due care. One method is to slide a tube whose ID is just larger than the pin's OD, over the pin and bend slowly and gently.

Semi-universal special tool [tm]:
In emergency situations (eg bent pin on CF card reader & far from home) a remarkably successful tool is a ballpoint pen with the tip retracted. The hole is much larger than the pin diameter but the pen tip fills much of the hole and the pin slides in between tip and barrel. Bend carefully. I have used a ball point pen for this purposes a number of times over the years to straighten pins when nothing else is available. Success rate is much larger than one may expect. Probably not suitable for BNC. May be :-).

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  • \$\begingroup\$ There's also the "finger" universal tool that IIRC works for BNCs :-) . At any rate, the OPs BNC looks OK so the difference in insertion force is probably unrelated to the pin being at a very slight angle. \$\endgroup\$ – Guy Sirton Feb 3 '13 at 23:47
  • \$\begingroup\$ In addition to ballpoint pens: mechanical pencils (0.5-0.9mm are useful standard sizes, depending on your pin size). Had good luck bending bent pins on old s478 Intel processors with such pencils =) \$\endgroup\$ – Shamtam Feb 4 '13 at 3:46
  • \$\begingroup\$ I tired using fingers, screwdrivers and pens, but it was impossible to bend the pin. In the end, I went back to the store I got it from and compared it to other probes of the same model. Turns out that they normally have straight pins. \$\endgroup\$ – AndrejaKo Feb 5 '13 at 7:28

I wouldn't worry about it. Bending the pin might cause it to snap and break. The pin is tapered so that it aligns and centers in the hole. That it isn't bent so much as to stop the connection is a good thing. As to the added friction, well it may eventually rub (grind) to be less or even straighten itself out just a little. The extra friction will just guarantee a more solid connection.

I think if you do choose to bend it back, have the skills for it, be gentle and know that there is now added stress in the pin.

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