There are various connection schemes, depending on which the variable resistor can be both a source of variable resistance and a potentiometer. It all depends on the type of connection of its third output.
Instructions
Step 1
Look carefully at the circuit itself or the documentation to establish how to connect the resistor in this particular case. As mentioned earlier, it can perform two functions: a variable resistance source and a potentiometer. The documentation should indicate the variable resistance value in this connection. It is best to determine this number by a practical method, using a special measuring device. So you can more accurately select a variable resistor or some equivalent.
Step 2
Take an ohmmeter to measure the total resistance in the circuit. Connect its terminal to the NO contacts. The resistance value should be displayed on the screen. Then measure the resistance at a specific node in the circuit. If the value is not reflected, then the connection is broken somewhere.
Step 3
Examine all contacts carefully. If necessary, connect them with any metal wire. You will make a more reliable connection when you solder the resistor. Select a suitable resistor depending on the value obtained. Start assembling it into the diagram.
Step 4
Solder out the old, broken resistor. Try to do this so that the remnants of the solder do not fall on the circuit, in order to avoid short-circuiting adjacent contacts. Then take a new variable resistor. Solder it in the same way as the one you just removed.
Step 5
Follow the same precautions to avoid bridging the pins. Turn on the circuit, check its performance. If it does not work or does not work properly, re-solder the resistor. On some foreign-made resistors, the contacts may be located a little differently. Swap the center contact with any of the outer ones. If this does not bring the expected results, use the device to check the serviceability of the new resistor.
