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                                                                 EXHIBIT 10.4(f)


    When recorded, mail to:
    STREICH-LANG, P.A.
    Renaissance One
    Two North Central Avenue
    Phoenix, Arizona 85004-2391
    Attn: Matthew Mehr, Esq.


                            MODIFICATION OF MORTGAGE
                                    (Indiana)


  DATE:         March 28, 1997

  DESCRIPTION OF MORTGAGE (the "Mortgage"):

           PARTIES: Mortgagor:              BOWMAR INSTRUMENT CORPORATION,
                                            an Indiana corporation

                             Mortgagor      5080 North 40th Street, Suite 475
                             Address:       Phoenix, Arizona 85018
                                            Attention:    Joseph G. Warren, Jr.

                             Bank:          BANK ONE, ARIZONA, NA,
                                            a national banking association.

                             Bank           Post Office Box 71
                             Address:       Phoenix, Arizona 85001
                                            Attention: Commercial Banking A593

           RECORDING
           DATA:                  Mortgage, Security Agreement, Assignment of
                                  Rents and Fixture Filing dated August 28,
                                  1995, by Mortgagor in favor of Bank, recorded
                                  November 17, 1995, in Instrument Number
                                  95-053967, official records of Allen County,
                                  Indiana.



FOR VALUE RECEIVED, IT IS AGREED AS FOLLOWS:

         1. The promissory notes and other indebtedness secured by the Mortgage
has been modified by that certain Third Modification Agreement of even date
herewith between Mortgagor and Bank (the "Third Modification Agreement"). In
addition, pursuant to the Third Modification Agreement, Bank has agreed to
provide Mortgagor with an additional revolving line of credit/term loan in the
principal amount of $1,200,000.00 (the "RLT") secured by, among other things,
the

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Mortgage. In connection with the modification of such indebtedness and the
extension of such additional credit, the Mortgage is hereby modified as provided
in this Modification.

         2. The Mortgage is hereby amended to secure, in addition to the
indebtedness and obligations of Mortgagor described therein, the obligation of
Mortgagor to repay all advances made by the Bank to the Mortgagor under the RLT.
Hereinafter, the term "Obligations," as defined in the Mortgage, shall include,
in addition to the other indebtedness described in the Mortgage, the RLT. The
final maturity date of the RLT is March 31, 2002.

         3. This Modification shall not affect or impair the lien or priority of
the Mortgage, as amended, with respect to the property subjected to the
Mortgage.

         4. All terms and provisions of the Mortgage shall remain in full force
and effect except as specifically modified herein and in the Third Modification
Agreement.

         5. This Modification may be executed in counterparts, all of which
executed counterparts shall together constitute a single document. Signature
pages may be detached from the counterparts and attached to a single copy of
this Modification to physically form one document.

         IN WITNESS WHEREOF, these presents have been executed as of the date
first written above.

                                        BOWMAR INSTRUMENT CORPORATION, an
                                        Indiana corporation


                                        By:    /s/ Joseph G. Warren, Jr.
                                               -------------------------
                                        Name:  Joseph G. Warren, Jr.
                                               -------------------------
                                        Title: Vice President
                                               -------------------------



                                                                       MORTGAGOR



                                       BANK ONE, ARIZONA, NA, a national banking
                                       association

                                       By:    /s/ Michael V. McCann
                                              -------------------------
                                       Name:  Michael V. McCann
                                              -------------------------
                                       Title: Vice President
                                              -------------------------

                                                                            BANK



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STATE OF ARIZONA         )
                         )ss:
County of Maricopa       )



         Before me, a Notary Public in and for the above County and State,
personally appeared Joseph G. Warren, Jr., the Vice President, of BOWMAR
INSTRUMENT CORPORATION, an Indiana corporation, who as such officer acknowledged
the execution of the foregoing Modification of Mortgage for and on behalf of the
corporation.

         WITNESS my hand and Notarial seal this 1st day of April, 1997.

                                              Signature: /s/ Cheryl A. Curtis
                                                        ---------------------
                                              Printed:  Cheryl A. Curtis
                                                        ---------------------
                                              Notary Public




                                                   "OFFICIAL SEAL"
                                [SEAL]             Cheryl A. Curtis
My Commission Expires:                          Notary Public - Arizona
                                                  Maricopa County
My County of Residence:                      My Commission Expires 3/3/2000





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STATE OF ARIZONA         )
                         )ss:
County of Maricopa       )

         Before me, a Notary Public in and for the above County and State,
personally appeared Michael V. McCann, the Vice President, of BANK ONE,
ARIZONA, NA, a national banking association, who as such officer acknowledged
the execution of the foregoing Modification of Mortgage for and on behalf of the
association.

         WITNESS my hand and Notarial seal this 10th day of April, 1997.



                                     Signature:  /s/ Joy L. Peckham
                                               ------------------------------
                                     Printed:    Joy L. Peckham
                                               ------------------------------
                                     Notary Public



                                               "OFFICIAL SEAL"
My Commission Expires:  2/27/99                 Joy L. Peckham
                        -------   [SEAL]      Notary Public-Arizona
                                                Maricopa County
My County of Residence: Maricopa             My Commission Expires Feb. 27, 1999
                        --------




THIS INSTRUMENT PREPARED BY:   /s/ 
                              -------------------------------------------------
                                           Attorney-at-law
                                           Streich Lang
                                           Renaissance One
                                           Two North Central Avenue
                                           Phoenix, Arizona 85004-2391
                                           Telephone:   (602) 229-5200


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