Armoury Tip 3 White light problems – Fault finding

Although electric fencing test boxes are available (at a price!) to check weapons you can’t beat a multimeter to really pin things down and they can cost less than £10!

They look complicated but are not, in fact I rarely use more than one setting on the selection dial; the 1- 200 Ω (Ohm) setting to measure electrical resistance.

The maximum resistance through the weapon from the socket is 2Ω. Pressing the point should open (break) the circuit (on a foil) and cause the meter to read 1,   being infinity. (Pressing the point on an epee closes (makes) the circuit which should thus move from infinity to 2Ohms).

There are several places you can test the weapon which are at each ‘joint’ in the circuit if you can call them ‘joints’! Some are just metal to metal contact ie dry joints. Any tarnish or loose connection between these will send resistance readings through the roof and trigger white lights.

1. From the socket. This tests the entire weapon circuit. Attach either crocodile clip (or use an adapted bayonet plug) to the socket connecting screw and the other to the metal socket frame (make sure it doesn’t go in too far and touch the brass disc as this will short straight over to the screw connector and all will look perfect!)

If the resistance reading wobbles either side of 2Ω wiggle the connectors to ensure a good connection. Or the point may need a twiddle to shine up the grub screws. They are only mild steel and tarnish quickly if unused! If over 10Ω, up to 100+ then you are probably looking for something more!

2. From bayonet socket screw to point tip. This tests the wire down the blade, through the point base, the spring and the point and avoids the internals of the socket. Known as the Positive side. It should read well under 2Ω and nearer 0.9 . If much more and it wobbles around it’s not looking good. Bend the blade up and down at different points. If the resistance is not stable or goes to infinity its probably a broken wire. But first… 

3. Check the socket screw to the brass contact inside the socket. The socket contains two dry joints, base to spring and spring to brass contact. I have also discovered damage to the socket at this point where guards have interlocked during a bout.

4. From the blade (anywhere you can get a good connection, blades are often lacquered) and bayonet socket frame. This is known as the Earth side. It tests the electrical circuit from the blade through the guard and where the guard meets the socket bracket behind the pad… If the reading is over 2Ω see if the handle needs tightening to squeeze these components tighter together and lower the resistance.

5. If there is still an issue, test blade to guard (tests the tang to guard connection) and guard to socket bracket. This should give you a definitive diagnosis!

Another indication that there is a fault on the earth side is when the box lights up with a hit on your guard by your opponent’s point.

You should now know where the fault (or more than one fault) is/are.

If the wire is ok and the earth side is ok then it is a point problem (see Armoury tip 2)

If the fault is earth side (blade, guard, socket) disassemble and clean.

Disassemble the hilt (see Armoury Tip 5) and use some fine emery paper to shine up the tang where it contacts the guard and also inside the guard where it contacts the socket bracket. Even the back of the socket bracket… Clean with contact cleaner/cloth and reassemble, be sure not to pinch the wire with the handle… and re-test.

If the fault is in the wire… Well, its probably rewire time… Off to an armourer or try Armoury Tip 4…

Return to the Armourer’s Bench

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