United States Nuclear Regulatory Commission - Protecting People and the Environment

ACCESSION #:  9502020175

A subsidiary of Thermo Instrument Systems Inc.


January 30, 1995

Nuclear Regulatory Commission
Document Control Desk
Washington, D.C. 20555

Subject:  Spare parts supplied for Westronics chart recorder models S4N, 
          D4N, T4N and 2100C.

Westronics has discovered that the possibility exists that some
nonconforming diodes may have ben used in safety related spare parts
provided for the above noted instruments.

The offering parts are generic 6.3 V zener reference diodes 1N825
(Westronics part number SE01N825-00).  These particular diodes are easily
identified as they are flat black in color with a gray band.  These
diodes were mixed in with other diodes received from an electronics
component distributor.

An internal purge was performed in August of 1994 in our commercial
production when the nonconforming diodes were discovered.  All existing
stock was purged because good and bad diodes were mixed together in
stock.  Westronics felt at the time that all of the bad components had
been accounted for.  However, service activity performed for GPU Nuclear
Oyster Creek in January, 1995 on some commercial recorders (D4E3)
revealed that some nonconforming diodes had been dedicated from our
commercial stock and supplied in safety related spare parts.

The 1N825 diode is used to generate reference voltages in the signal
conditioning circuits of the noted instruments.  The nonconforming diodes
are "noisy" and cause a drift in calibration of the host instrument.  The
diodes are found on the CB100124N02 and CB100124N04 signal input boards
for the S4N, D4N and T4N series and the CB100243C01 ADC board for the
2100C series.

Westronics has been able to precisely determine which customers may have
received spare parts with the bad diodes.  A list of affected license
holders and other recipients ia attached for your reference.  All
customers on the list have received a similar notification.

Customers may obtain replacements or return boards for repair by
contracting Westronics Recorder Service department at 1-800-433-2184.

For further information, please contact the undersigned at (713) 348-1780


Westronics Inc.

Chris Kelly
Quality Assurance Manager

    P.O. Box 4500 o 22001 North Park Drive o Humble, Texas 77347-4500
                 Phone: 713/348-1800 o Fax: 713/348-1288

List of Affected Customers:

Customer                           Part Number    Lot Number     Qty

Entergy Operations - River
     Bend Station                  CB100124N04    0037510         1

Florida Power - Turkey Point 
     Plant                         CB100124N04    0037510         1
                                   CB100124N04    0049330         1
                                   CB100243C01    0036510         2
                                                  Supplied as
                                                  KT100161C03 kit

New York Power - J.K. Fitzpatrick 
     Plant                         CB100124N04    0049330         1

Taiwan Power Company               CB100124N04    0037510         3

Victoreen Inc.                     CB100124N02    0048910        15


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