ODYSSEY 2.4G DIODE LASER

Description of Event or Problem

OPERATOR OF DEVICE REPORTED THAT WHEN THE FOOT PEDAL WAS PRESSED TO ACTUATE THE LASER, THE UNIT WOULD CONSISTENTLY RETURN AN ERROR MESSAGE AND THE OPTICAL FIBER TIP WAS SMOKING. THE UNIT WAS RETURNED TO THE MFR FOR SERVICING. DURING TESTING OF THE UNIT'S PERFORMANCE, IT WAS DISCOVERED THAT LASER EMISSIONS WERE IN EXCESS OF 20% OF SETTING AS DICTATED BY 21 CFR 1040.10. BECAUSE THE EMISSIONS WERE EXCESSIVE AT THE PROSCRIBED SETTINGS, A THREAT TO HEALTH EXISTS WITH THIS UNIT AND IS THEREFORE REPORTABLE. NO INJURY OR DAMAGE WAS REPORTED.

Additional Manufacturer Narrative

INVESTIGATION REVEALED THAT THE EMISSIONS ERROR RESIDES WITHIN THE CLOSED-LOOP MONITORING SYSTEM THAT GOVERNS LASER MODULE. INTERCHANGING CIRCUIT BOARDS AND LASER MODULES WITH OTHER KNOWN GOOD SPECIMENS RULED OUT ELECTRONIC, CONTROL, OR SOFTWARE ISSUES WITH THE CIRCUIT BOARD AND ISOLATE THE FAILURE TO A WIRE HARNESS THAT CONNECTS THE LASER MODULE WITH THE CIRCUIT BOARD. A SHORT IN THE WIRING OF THE CLOSED-LOOP FEEDBACK SIGNAL PROVIDES ERRONEOUS SIGNALS TO THE CONTROL PROCESSOR. THE PROCESSOR THEN INCORRECTLY THINKS THE LASER MODULE IS UNDERPOWERED AND SUPPLIES MORE POWER TO THE LASER MODULE. THIS RESULTS IN EMISSIONS THAT ARE GREATER THAN THE DISPLAYED VALUE. THE INCREASE IN POWER CONTINUES UNTIL AN UPPER LIMIT IS REACHED, WHEN THE PROGRAMMING CAUSES A REDUNDANT FAILSAFE IN THE DEVICE TO SHUT DOWN THE LASER EMISSIONS AND PRESENT AN ERROR MESSAGE TO THE OPERATOR. THE SHORT CIRCUIT OCCURRED WHERE THE WIRE TERMINATIONS ARE CRIMPED INTO A CONNECTOR SOCKET AND FITTED INTO THE CONNECTION TERMINAL. THE INSULATION WAS NOT SUFFICIENTLY STRIPPED BACK, AND THE CRIMP PARTIALLY COVERED THE INSULATION. THE EXTENT OF THE CRIMP WAS NOT SUFFICIENT TO PENETRATE THE INSULATION AND MAKE RELIABLE CONTACT WITH THE CONDUCTIVE WIRE. MOVEMENT OR ORIENTATION OF THE DEVICE WOULD CAUSE THE WIRE TO MOVE AND THUS AFFECT THE EXTENT OF CONTACT BETWEEN THE CRIMP TERMINAL AND THE WIRE. THE EXCESSIVE EMISSIONS WOULD HAVE CAUSED THE OBSERVED "SMOKING AT THE TIP" REPORTED BY THE OPERATOR. THE RESPONSE OF THE ELECTRONICS FOR THE REDUNDANT MONITOR MECHANISM TO ACKNOWLEDGE THE ERROR AND INITIATE THE SHUT DOWN HAS A RESPONSE TIME OF APPROX 0.02 SECONDS. A RISK ASSESSMENT WAS PERFORMED IN TERMS OF THIS FAILURE. THIS ASSESSMENT ASSIGNS A NUMBER BASED ON A LEVEL OF RISK, WITH 0 BEING NO RISK AND 10 BEING EXTREME RISK. FURTHER, THE RISK WAS EVALUATED IN TERMS OF HOW OFTEN THE FAILURE IS LIKELY TO OCCUR, THE SEVERITY OF THE FAILURE IF IT SHOULD OCCUR, AND THE POINT IN THE PRODUCT'S LIFE CYCLE THAT THE FAILURE DID OR IS LIKELY TO OCCUR. THE FAILURE AS DESCRIBED IS ATTRIBUTED TO ONE LOT OF WIRE HARNESS THAT CONNECTS THE LASER MODULE TO THE MAIN PRINTED CIRCUIT BOARD ASSEMBLY. THERE IS A POTENTIAL OF 1039 UNITS THAT CONTAIN THE SUSPECTED LOT OF WIRE. TO DATE, ONLY ONE OCCURRENCE OF THE SHORTING ISSUE HAS BEEN IDENTIFIED. THIS PROVIDES A FREQUENCY OF FAILURE OF <1 IN 1000 FOR A RISK SCORE OF 3. SHOULD THE FAILURE OCCUR, THERE WILL BE NO WARNING TO THE OPERATOR THAT THERE IS A FAILURE. IF THE FAILURE OCCURS, IT IS POSSIBLE THAT SAFETY AND COMPLIANCE OF THE DEVICE IS COMPROMISED. THIS YIELDS A SEVERITY RISK SCORE OF 10. THE POINT AT WHICH THE FAILURE HAS OCCURRED RELATIVE TO THE LIFECYCLE OF THE PRODUCT IS PLACED AT 97% OF THE PRODUCT'S EXPECTED SERVICE LIFE OF 5 YEARS. THIS IS BASED ON THE ONE FAILURE UNIT WHICH WAS MFG IN OCTOBER 2005 AND THE FAILURE OCCURRING IN (B)(6) 2010. THIS YIELDS A TIMEFRAME RISK SCORE OF 2. THE AVERAGE VALUE OF THE THREE RISK SCORES GENERATES AN OVERALL RISK SCORE OF 5.0. THIS RISK IS THEN EVALUATED IN TERMS OF THE ACTUAL OUTCOME OBSERVED WITH THIS PARTICULAR FAILURE. IN THIS CASE, THE PRIMARY CONTROL MECHANISM FAILED, YET A REDUNDANT SAFETY MECHANISM DID WORK AND SERVED TO SHUT DOWN LASER EMISSIONS WHEN THE REDUNDANT MECHANISM DETECTED THE FAILURE. THE RESPONSE TIME BETWEEN WHEN THE REDUNDANT SAFETY FEATURE DETECTED THE ERROR AND LASER EMISSIONS WERE INTERRUPTED IS ESTIMATED TO BE 0.02 SECONDS, BASED ON THE PROCESSOR CLOCK SPEED OF THE MICROCONTROLLER. AT THIS TIME, THE FAILURE IS SUSPECTED WITHIN ONE LOT OF WIRE HARNESSES WHICH WERE CONSUMED BY (B)(6) 2006. ALL SUBSEQUENT LOTS OF THE WIRE HARNESS HAVE HAD AN INCOMING QUALITY CONTROL TEST UPON RECEIPT TO EVALUATE THE ROBUSTNESS OF THE CONNECTORS AND RELEASE THE PART FOR MFG USE. THIS QC TEST WENT INTO EFFECT IN (B)(6) 2005. BECAUSE THE REVIEW RISK RECEIVED A SCORE OF 5.0 ON A SCALE OF 0 TO 10, AND BECAUSE THE REDUNDANT SAFETY MECHANISM FUNCTIONED IN THIS INSTANCE, IT IS DETERMINED THAT NO FURTHER CORRECTIVE ACTION WILL BE INITIATED, BEYOND THE IMPROVED WIRE HARNESS PROCESS AND INSPECTION TESTS THAT WERE ALREADY INSTITUTED AS PREVIOUSLY MENTIONED.