GentleLASE PRO DCD Pressure and Bubble Verification Procedure
WARNING – SHOCK HAZARD!!!
The high voltage capacitor in the GentleLASE PRO laser retains LETHAL voltages and must be safely discharged, before working near the laser head or inside the HV section for any reason. This procedure must be performed only by those technicians who are familiar with the precautions required when working with high voltage specific to the GL PRO laser system, and those who have been trained on the GL PRO laser system and its particular hazards.
Residual voltages require stick discharging if access to the head or high voltage sections are necessary. This must be done using the discharge stick located in the HV section. Discharge all 3 capacitor terminals for several seconds each. Verify that the capacitor is discharged below 25 VDC using a DVM and a high voltage probe.
WARNING – LASER LIGHT!!!
During this procedure it is possible that the laser may perform a bleeder pulse, emitting laser radiation. Therefore safety eyewear must be worn at all times during these procedures. The eyewear must have an optical density of ≥ 5.8 at 745 – 765 NM for the Alex Head.
NOTE: If the OPHIR NOVA display is used, be sure the wavelength is set to “YAG, NIR or .8-6”, depending on the meter head being used.
DCD PRESSURE VERIFICATION PROCEDURE:
- Turn laser on, allow for normal warm up, and enter Maintenance Mode (MM). CAUTION!!! The following tests will cause cryogen to be sprayed from the handpiece. Make sure to hold the hanpiece so that the spray nozzle faces down toward the floor. Do not spray into the calport. If the handpiece is held in your hand, be sure to aim it away from yourself and others.
- The cryogen canister must be warmed up to a pressure of greater than 115 PSI in order to start these tests. The cryogen is fully warmed up when the canister pressure on the maintenance screen is between 118 and 125 PSI. ATTENTION!!! The pressure transducer must be purged and reset to zero before each measurement. Connecting the pressure transducer that has not been purged to zero will result in erroneous measurements.
- Disconnect the delivery system DCD cable from the bulkhead and connect the pressure transducer to the bulkhead fitting. Select Toggle screen, press the Mode button to select Manual control. Turn the DCD heater OFF by entering 0%, and turn DCD Fan to OFF. Verify DCD Fan is OFF and press the Pressure Cal button. Enter the reading from the pressure transducer to calibrate the DCD pressure.
- Allow the system to stabilize and adjust tot the calibrated pressure and verify the DCD Pressure displayed on the Toggle screen and Transducer agree with +/- 2 psi them remove the Transducer.
- Connect a DVM to the Hand Piece Bubble Sense Test Points on the CPU I/O PCB at TP51 (+) and TP47 (-). Verify the “no bubble” voltage is 7.75 VDC ± 0.75 VDC, (7.00 – 8.50V).
- Disconnet the HP cryogen line from the front panel bulkhead connector. Set DCD settings to Pre 50 and Delay 50. Turn the DCD valve on by repeatedly pressing and holding the HP Purge button until the cryogen line is completely empty and sprays no more cryogen. Verify the voltage on the CPU I/O PCB at TP51 (+) and TP47 (-) is greater than 10.25 VDC. Also, verify that the HP Bubble Status changes from “Not Present” to “Present”. HP Bubble Voltage should be (>10.25V).
- Reconnect the HP cryogen line to the front panel bulkhead connector. Verify that within two minutes, the HP Bubble Status changes from “Present” to “Not Present” and the HP no bubble voltage on the CPU I/O PCB at TP51 (+) and TP47 (-) is 7.75 VDC ± 0.75 VDC.
- Press the HP Bubble Test button and verify the status changed to Passed.
- Connect DVM to the Canister Bubble Sense Test Point on the CPU I/O PCB at TP49 (+) and TP47 (-). Verify Canister no bubble voltage is 7.75 VDC ± 0.5 VDC, (7.25 – 8.25V).
- Verify that the HP cryogen line is connected to the front panel bulkhead connector. Remove the canister from the DCD Assmebly. Set DCD settings to Pre 50 and Delay 50. Turn the DCD valve on by repeatedly pressing and holding the HP Purge button until the cyogen line is completely empty and sprays no more cryogen. Verify the bubble voltage on the CPU I/O PCB at TP49 (+) and TP47 (-) is greater that 11.0 VDC (>11.0). Also verify that the Canister Bubble Status changes from “Not Present” to “Present”.
- Re-install the canister into the DCD assembly. Verify that within two minutes, the Canister Bubble Status changes from “Present” to “Not Present” and Canister no bubble voltage on the CPU I/O PCB at TP49 (+) and TP47 (-) is 7.75 VDC ± 0.5 VDC, (7.25 – 8.25V).
- Press the Canister Bubble Test button and verify the status changed to Passed.
- Connect the delivery system DCD cable to the bulkhead fitting.