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Probe Maintenance - ensuring low-noise performance
The EmD sensor sets up has a high-voltage electric field in the space behind the diaphragm. Diaphragm movement modulates this field, such that extremely small vibrations of the diaphragm are directly detected as field changes. For proper operation, the space in which the field exists must be clean and dust- and lint-free, and not contain excess moisture.
Under normal circumstances, the field will remain clean, and require no maintenance. However, if dust, lint or moisture do enter the Probe, unexpected background or louder noises can occur. The simple cleaning procedures below can then be used to rapidly re-establish noise-free operation, using a standard alcohol swab. These procedures are described in great detail for clarity. However, they are simple, and take less than 2 minutes to complete.
Noise Symptoms
Dust, lint or moisture in the field produces the following possible symptoms:
- intermittent faint white-noise.
- squealing sounds, either faint or more prominent.
- ticking sounds (static discharges).
- above artifact sounds change when the diaphragm is pressed or unscrewed slightly.
If you notice any of these symptoms, follow the cleaning procedures below. If your ds32a+ is operating well, these procedures are not required for regular maintenance.
Alcohol Cleaning
- Make sure the unit is turned off.
- Unscrew the diaphragm as described above. Open the probe in a clean, dust-free environment, and place the open part of the probe face-up. DO not touch the brass plate. Do not place the open probe on a dusty surface or a cloth surface. Lint could be attracted into the Probe.
- Using the alcohol swab, carefully wipe the brass plate inside the Probe. Do not touch the brass plate. This could permanently damage the sensor.
- Using a lint-free alcohol swab, carefully wipe the inner surface of the diaphragm as shown. Do not touch the inner plastic surface of the diaphragm with anything other than the alcohol swab.
- Allow the diaphragm and probe surfaces to dry by evaporation. Do not close the unit and power it up with alcohol moisture on the diaphragm. Only after evaporation will the surfaces be clean and ready for use.
Air Drying and Cleaning
The probe can further be cleaned using a dry air aerosol spray. These are available at hardware or office supply store, and are usually used for cleaning computers. This cleaning method is useful when the unit has been exposed to extreme dust, lint, humidity or moisture, or in addition to the alcohol-swab cleaning described above, the rare instance than contaminants exist inside the probe.
- Make sure the unit is turned off.
- Rotate the Aperture Ring to the open position to allow air flow in the Probe.
- Unscrew the Diaphragm Ring and remove the diaphragm. Place the diaphragm with Thinklabs logo face DOWN, so the inside surface does not become dusty.
- Using the dry air spray with the spray’s plastic straw, spray the inside of the probe via the vent holes in the Aperture Ring, and around the circumference of the brass plate. Do not touch the brass plate with anything, including the plastic straw. Do not overspray. White condensation sometimes forms, which is counterproductive when trying to dry out the Probe.
- Replace the Diaphragm, and close the Aperture Ring. Wait a few minutes for the Probe to stabilize, and then power up the unit to test.
If these cleaning procedures do not correct the problem, see Tips and Troubleshooting and contact Thinklabs. We can assist you and ensure that your ds32a+ is operating optimally.
