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ACCESSION #: 9603280019 FOXBORO The Foxboro Company Foxboro, MA U.S.A. 02035-2099 Telephone: 508-543-8750 Telex: MCI-6817560 Fax: 508-549-6770 7 March 1996 U.S. Nuclear Regulatory Commission Document Control Desk 1155 Rockville Heights Mail Stop 0-9A1 Rockville, Maryland 02852 Attn: Chief of the Special Inspection Branch Gentlemen: Per our telephone conversation yesterday (6 March 1996) with Mr. Greg Cwalina, Mr. Robert Pettis, and Mr. Steve Alexander, enclosed is a copy of the letter which will be mailed to seven customers in the United States and five customers outside the United States. Very truly yours, Richard A. Anderson, Manager Quality Systems and Compliance baa(2996) SIEBE A SIEBE COMPANY FOXBORO The Foxboro Company Foxboro, MA U.S.A. 02035-2099 Telephone: 508-543-8750 Telex: MCI-6817560 Fax: 508-549-6770 March , 1996 ABC Utilities P.O. Box ABC Nuclear Power Generating Station ABC, State Zip Attention: Utility VP, Nuclear Operations Dear Mr : Reference: Foxboro Sales Order No. 92F-XXXXX y/ Customer Purchase Order No. bXXXX Model N-82Z Transmitter In compliance with 10CFR Part 21.21C this letter is to inform you of a potential failure with N-820 Series transmitters with analog output as referenced above. The N-820 Series transmitters have electronics modules which may have a potential to fail if exposed to high ambient thermal cycles during the transmitter application. Plated pins within the module which are used as the transmitter sensor connections have the potential to experience delamination of the plating. As delamination occurs the connection impedance changes, whereby the transmitter current output will shift 0.2% and/or become intermittent or fail. Intermittent means that the transmitter output will decrease to 0% output from any output level, downscale is always the failure direction. To date there have been no transmitter module failures with the N-820 series model codes in any nuclear facility world wide. The failures have been of the 820 series commercial grade type and only in specific world regions. The failures have been in outdoor applications in the MiddleEast, Southeast Asia and the US Southwest. These regions experience some the largest diurnal changes in the world. Of 25,000 transmitters shipped since 1992 only 90 failures(0.36%) have been identified recently as pin related failures. The 820/N-820 series potted electronics modules will fail if high thermal cycles exist in common with potting stresses present on the pins. Modules with date codes of 9201 to 9545 have been targeted as the potential failure units. All pin stock was purged and a new pin process, monitoring and quality measurements have been implemented. This notification is to allow each user to make an assessment of their application of the model transmitters specified above and determine their course of action. Transmitters with N-820.. -I or H analog model codes and module date codes earlier than 9545 should be replaced. SIEBE A SIEBE COMPANY FOXBORO A SIEBE COMPANY Page 2 N-820 modules in stock as replacement modules should also be replaced. The following are the N-820 Series electronics module part numbers which should also be replaced: BO139FZ BO139FY BO138RB BO138RA BO139EZ BO139EY DO135PZ DO135PY DO139GM DO139GL Questions regarding this notification and the replacement procedure should be directed to: Mr. James Keiper 508-549-6332 Truman L. King Director, Corporate Quality and Product Safety baa(2896) *** END OF DOCUMENT ***