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TN 219 Arm Position Contact Cleaning

Tech Notes –  TN 219 Arm Position Contact Cleaning
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Technical Note 219

TN 219 Arm Position Contact Cleaning

Introduction

Some DeNovix products include a patented mechanism for detecting that the arm has been lowered to the “down” or “closed” position. On rare occasions, a resistive layer can build up and need to be removed.  The contact button in the arm and the screw head will need to be cleaned to remove the resistive layer so the mechanism can function properly. This technical note describes the steps for refurbishing these components and restoring proper function.

Arm Contact and Screw

Normally when the arm is down, an electrical circuit is completed between the contact button (Figure 1 – ① ) in the arm and the head of the screw (Figure 1 – ② ). The instrument reliably detects this contact. However, if there is contamination or an oxidized layer interfering with the two contact points, a “Lower Arm” alert may be present even when the arm is in the down position. Ethanol cleaning following the steps below will remove the resistive layer.

arm_up
Figure 1.

Ethanol Cleaning of Contact Points

  1. Spray a standard laboratory wipe with 70% ethanol. Do not pour or douse the instrument directly with the fluid.
  2. Lift the instrument arm.
  3. Using the lab wipe, vigorously clean the contact button located on the bottom of the arm (Figure 2).
  4. Repeat this process and clean the top of the screw. (Figure 3).
clean1
Figure 2.
clean2
Figure 3.

24-JUL-2026

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