Clean that Rotary Selector Switch!

Wouldn't you know it..my trusted and long time friend MASTECH MY68 failed to turn on!

Oh my! Batteries must need replacing...Changed. Uh-Oh...Nothing..

After careful inspection I noticed the selector tracks were in dire need of a proper cleaning and had dirt all over them.

Cleaning a multimeter's rotary selector switch can help improve its performance and ensure accurate measurements. Here's a step-by-step guide on how to clean the rotary selector switch:

1. Disconnect Power: Before cleaning any electrical device, always disconnect the power source to ensure your safety.

2. Gather Cleaning Supplies: You'll need some basic cleaning supplies, including electronic contact cleaner, isopropyl alcohol (at least 90% concentration), cotton swabs, and a small brush.

3. Prepare the Multimeter: Set the multimeter's rotary selector switch to the "Off" or "Zero" position.

4. Spray Electronic Contact Cleaner: Use a can of electronic contact cleaner and spray a small amount directly onto the rotary selector switch. The cleaner will help dissolve any dirt, dust, or oxidation that may be affecting the switch's performance.

5. Rotate the Switch: After applying the cleaner, rotate the selector switch back and forth several times. This helps distribute the cleaner and dislodge any debris or contaminants that may be causing issues.

6. Remove Excess Cleaner: Use a clean, dry cotton swab to remove any excess cleaner or dirt that comes off the switch. Be gentle to avoid damaging the switch or any surrounding components.

7. Clean with Isopropyl Alcohol: Dip a cotton swab in isopropyl alcohol and gently clean the switch contacts. The alcohol helps remove any remaining residue and provides further cleaning. Ensure the cotton swab is not too wet to prevent liquid from dripping into the multimeter.

8. Now add some Dielectric on those tracks. Not too much is needed just a bit goes along way and helps to increase the longevity of the tracks.

9. Brush Away Debris: Use a small brush, such as a soft toothbrush or a small paintbrush, to gently brush away any loose dirt or debris from the switch and surrounding area.

10. Allow Drying: Let the multimeter air dry completely before reassembling or using it again. This ensures that any residual moisture evaporates.

11. Reassemble and Test: Once the multimeter is dry, reassemble any removed parts and reconnect the power source. Test the rotary selector switch by rotating it through the different positions and verifying smooth operation.

Footnote: The older a multimeter gets. The greater the chance that dirt and sludge may affect the selector tracks and degrade your meter's performance., There's no such thing as a multimeter that's too old. Take care of your precious test instrument and it will take care of you.

Note: Always follow the manufacturer's guidelines and recommendations for cleaning your specific multimeter model. Some multimeters may have sensitive components that require special cleaning considerations. If in doubt or if the switch still does not function properly after cleaning, consult the manufacturer's customer support or consider professional servicing.