Avometer Cut-Out Repair

The Avometer cut-out mechanism sometimes does not lock into place, and when you push the cut-out knob, it does not stay in. In this article, we look at some of the basic simple things you can so to repair it.

Firstly, people often do not realise, that it only works when the meter is lying on its back, which is the proper way to use the meter. Usually the cut-out knob will not lock in if the meter is upright.

The locking mechanism itself is very simple and mounted on a brass base plate. There is a locking lever and latch arrangement, as shown in the header section of this article. When properly locked it should appear as shown in the photograph. The lever remains locked on a sharp knife-edge point, and when an overload occurs, the slightest movement causes it to release from the latch. These metal components slide over each other, and therefore if there is dried grease or insufficient lubrication, then the lever will stick and not lock with the latch. Usually a little contact cleaner helps especially if there are signs of oxidation or rust.

There is also a wire spring, which pushes one end of the lever up to bring it into a locking position. This thin wire spring produces a very small force, and therefore if the lever is sticking to the base plate, then it will not lock into the latch. I have had meters where the spring was missing, and sometimes the lever sticking. Most of the time it is lubrication issue because the mechanism design is very good.

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