Why do I receive “No Crystal”, “-2”, or ”-3” for the crystal frequency?

If the term “No Crystal” is shown in the software’s status screen, the graph screen shows a “-3” or “-2”, or the RS232 communication is reporting a -2 or -3 from the unit is indication that the Eon™ unit is not receiving a signal from the crystal of the sensor head. This issue is generally due to a hardware issue, and generally not related to the software.

This can be caused by the following issues:
   1. The crystal is not properly seated
          a. Causes
                    i. The crystal was dislodged from the crystal pocket when screwing down the back                         plate of the sensor cap.
          b. Solution
                    i. Replace the crystal that is currently inside of the sensor head with a new                         one.

   2. The crystal you are using is outside of the frequency range of the system or malfunctioning
          a. Causes
                    i. The system can read frequencies from 6.1Mhz to 4.5 Mhz. Any frequency outside                         of this range will not be recognized by the device.
          b. Testing
                    i. Insert a new 6 Mhz crystal into the sensor head.
                    ii. If the frequency appears, there was an issue with the previous crystal.
          c. Solution
                    i. Use a new crystal
                    ii. Ensure the crystals used with the unit are 6Mhz crystals.

   3. A bad connection between the crystal and the oscillator or Eon™ unit.
          a. Causes
                    i. This can happen if there are bad cables, or the sensor head is not connected                         correctly. Loose adaptors can also cause this issue.
          b. Testing
                    i. Testing the center pin
                              1. Simply unplug the sensor head from the Eon™ or from the external oscillator                                   if one is being used.
                              2. Remove the cap of the sensor head. Leaving the spring in place.
                              3. Set the multimeter to measure resistance.
                              4. Without touching the spring, touch one lead of the multimeter to the screw                                   in the center of the spring.
                              5. Touch the other lead of the multimeter to the center pin of the BNC cable                                   that would normally connect to the Eon™ unit, or external oscillator if used.
                              6. You should see a resistance of approximately 2 ohms or less.
                                            a. If you see no resistance (OPEN) then there is a cable that is not                                                 making connection.
                                            b. If you see a much higher resistance then it could be that the                                                 cables are not seated correctly.
                    ii. Testing the ground
                              1. Set the multimeter to measure resistance.
                              2. With the sensor head cap screwed into the sensor head, touch one lead of                                   the multimeter to the top of the cap of the sensor head.
                              3. Touch the other lead of the multimeter to the outside of the BNC connector
                                  that screws into the Eon™ unit.

          c. Solution
                    i. Ensure that all cables are connected correctly.
                    ii. Make sure all cable connections are secure.
                    iii. Replace the cables being used.

   4. Debris build around crystal in sensor head.
          a. Causes
                    i. The sensor head has been used though several deposition runs without being                         cleaned.
                    ii. Debris builds up behind and around the crystal in the pocket it sits in                         after several runs.
          b. Testing
                    i. Unscrew the cap of the sensor head
                    ii. Remove the back plate of the sensor head cap where the crystal resides
                    iii. Visually inspect the crevasse and corners to ensure there is no observable debris
                    iv. Even if no debris is visible, there can still be material build up preventing the                         crystal from oscillating freely.
          c. Solution
                    i. Clean the pocket where the crystal sits lightly with a scouring pad                        and isopropyl alcohol. (Do not use a steel scrubber or a Brillo Pad®)
                              2. ENSURE THAT NO ADDED PRESSURE IS APPLIED TO THE SPRING DURING THIS                                   PROCESS
                              3. To clean the spring, take an X-Acto® knife and gently scraped the top of the                                   spring which makes contact with the crystal. ONLY do this to the top rung of                                   the spring that makes physical contact with the crystal.
                                            a. This will remove and debris build up on the top of the spring,                                                 preventing it from making an electrical contact with the crystal.

   5. The BNC between the sensor head and the Eon™ or oscillator is too long.
          a. Notes:
                    i. The total length of wire between the crystal in the sensor head and                         the Eon™ unit must be under 36 inches.
                              1. This is not the distance from the flange to the Eon™ unit;                                   it is the distance from the actual crystal to the Eon™ unit.
                    ii. While exceeding this limitation will not result in an immediate signal                         failure, it can cause the signal to be much weaker resulting in inaccurate readings                         or no signal at all. Industrial noise and interference from the surrounding                         environment can have a much bigger impact on the signal.
                    iii. If a longer distance is needed than 32 inches, an external oscillator                         can be purchased to increase the length, however, the unit will also need to be                         modified by Colnatec to allow it to use the external oscillator
          b. Causes
                    i. The BNC cable installed between the flange and the Eon™ or oscillator causes the                        total length to exceed 32 inches.
          c. Other Symptoms
                    i. The signal is intermittent
          D. Solution
                    i. Use a shorter cable between the sensor head and the Eon™ or oscillator unit.

   6. The external oscillator being used is backwards. (If the unit was purchased as an external        oscillator unit, or is an Eon™ unit).
          a. Causes:
                    i. The external oscillator was connected incorrectly
          b. Testing
                    i. Check to see that the labeling on the oscillator is connected correctly as indicated.
                    ii. If not, try flipping the oscillator in place
                    iii. If a frequency appears in the software, then the oscillator is connected correctly.
          c. Solution
                    i. Continue using the oscillator in the correct orientation.

   7. The unit is set for external oscillator, but the oscillator is not being used with the system.
          a. Notes:
                    i. If the unit is setup to use an external oscillator, it must be used with an external                        oscillator, even if a shorter BNC cable is used.
                    ii. If the unit was purchased as an internal oscillator no external                        oscillator is required.
          b. Causes:
                    i. Customer requested unit as external oscillator, but the user has not connected the                        oscillator in line with the BNC cables that go to the head.
          c. Testing
                    i. Connect the Colnatec Oscillator in line with the BNC cables connected from the                        Eon™ unit to the sensor head.
                    ii. If a frequency appears in the software then the unit is set to an external oscillation                        unit.
          D. Solution
                    i. If you now see the frequency in the software, continue using the external oscillator.