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                                  EXHIBIT 10.4

      TERMINATION, REPLACEMENT AND RESTATEMENT AGREEMENT (this "TRR Agreement")
dated as of March 6, 1998, of the 364-day Competitive Advance and Revolving
Credit Facility Agreement dated as of March 21, 1994, among EG&G, INC., a
Massachusetts corporation (the "Company"), the Borrowing Subsidiaries (as such
term is defined therein; together with the Company, the "Borrowers"), the
financial institutions listed in Schedule 2.01 hereto under the caption
"Lenders" (the "Lenders") and THE CHASE MANHATTAN BANK (as successor to Chemical
Bank), a New York banking corporation, as administrative agent (in such
capacity, the "Administrative Agent") for the Lenders. Capitalized terms used
and not defined herein shall have the meanings assigned to such terms in the New
Credit Agreement (as defined below).


      WHEREAS, the Borrowers, the Lenders, and the Administrative Agent are
parties to a 364-day Competitive Advance and Revolving Credit Facility Agreement
dated as of March 21, 1994 (as amended, the "Original Credit Agreement");

      WHEREAS, the Original Credit Agreement is to be terminated as provided
herein; and

      WHEREAS, the Lenders are willing, subject to the terms and conditions of
this TRR Agreement, to replace the Original Credit Agreement with a new credit
agreement as provided herein.


      NOW, THEREFORE, in consideration of the mutual agreements contained in
this TRR Agreement and other good and valuable consideration, the sufficiency
and receipt of which are hereby acknowledged, the parties hereto hereby agree as
follows:

      SECTION 1. TERMINATION, REPLACEMENT AND RESTATEMENT. Subject to the
conditions set forth in Section 3 hereof:

      (a) the Original Credit Agreement, including all schedules and exhibits
thereto, is hereby terminated, subject to applicable provisions set forth
therein as to the survival of certain rights and obligations, and simultaneously
replaced by a new credit agreement (the "New Credit Agreement") identical in
form and substance to the Original Credit Agreement except as expressly set
forth below.



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      (b) The heading of the New Credit Agreement shall read as follows:

          "364-DAY COMPETITIVE ADVANCE AND REVOLVING CREDIT FACILITY AGREEMENT
          dated as of March 6, 1998, among EG&G, INC., a Massachusetts
          corporation (the "Company"), the Borrowing Subsidiaries (as such term
          is defined herein; together with the Company, the "Borrowers"), the
          lenders listed in Schedule 2.01 (the "Lenders") and THE CHASE
          MANHATTAN BANK, a New York banking corporation, as administrative
          agent for the Lenders (in such capacity, the "Administrative Agent")."

and all references to the "Closing Date" in the New Credit Agreement shall be
deemed to refer to March 6, 1998.

      (c) (i) The definition of "Amendment Effective Date" is hereby deleted in
its entirety.

          (ii) The definition of "Maturity Date" in Section 1.01 of the New
Credit Agreement shall read as follows:

"'Maturity Date' shall mean March 5, 1999."

      (d) The reference to "March 31, 1996" in Section 2.05(a) of the Original
Credit Agreement shall be changed to a reference to "March 31, 1998" in the New
Credit Agreement.

      (e) Section 3.04(a) of the New Credit Agreement shall read as follows:

          "The Company has heretofore furnished to the Administrative Agent and
          the Lenders copies of its consolidated financial statements as of and
          for the fiscal year ended December 31, 1996, and as of and for the
          period of nine months ended September 30, 1997. Such financial
          statements present fairly, in all material respects, the consolidated
          financial condition and the results of operations of the Company as of
          such dates and for such periods in accordance with GAAP."

      (f) Section 4.02(d) of the New Credit Agreement shall read as follows:

          "The commitments under the 364-day Competitive Advance and Revolving
          Credit Facility Agreement dated as of March 21, 1994, among the
          Borrowers, the lenders party thereto and The Chase Manhattan 

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          Bank, as administrative agent shall have been terminated and all
          principal, interest and other amounts outstanding thereunder
          (including all Fees accrued thereunder to the Closing Date) shall have
          been paid in full."

      (g) The references to "March 21, 1994" in Exhibit A-1, Exhibit A-2,
Exhibit A-3, Exhibit A-4, Exhibit A-5, Exhibit C, Exhibit D-1, Exhibit D-2 and
Exhibit E of the Original Credit Agreement shall be changed to references to
"March 6, 1998" in the New Credit Agreement.

      (h) Schedule 2.01 to the New Credit Agreement shall be in the form of
Schedule 2.01 to this TRR Agreement.

      SECTION 2. REPRESENTATIONS AND WARRANTIES. The Company represents and
warrants to each of the Lenders that:

      (a) This TRR Agreement and the New Credit Agreement have been duly
authorized and, in the case of this TRR Agreement, executed and delivered by it
and constitute its legal, valid and binding obligations enforceable in
accordance with their terms.

      (b) The representations and warranties set forth in Article III of the New
Credit Agreement, after giving effect to this TRR Agreement, are true and
correct in all material respects on the date hereof with the same effect as if
made on the date hereof, except to the extent such representations and
warranties expressly relate to an earlier date.

      (c) Before and after giving effect to this TRR Agreement, no Default has
occurred and is continuing.

      SECTION 3. CONDITIONS TO EFFECTIVENESS. This TRR Agreement shall become
effective as of March 6, 1998 (the "Effective Date") upon the occurrence of the
following conditions precedent:

      (a) The Administrative Agent shall have received counterparts of this TRR
Agreement which, when taken together, bear the signatures of all the parties
hereto.

      (b) The Administrative Agent shall have received, on behalf of itself and
the Lenders, favorable written opinions of General Counsel for the Company,
substantially to the effect set forth in Exhibit D-1 of the Original Credit
Agreement but referring to this TRR Agreement and the New Credit Agreement, (i)
dated the date hereof, (ii) addressed to the Administrative Agent and the
Lenders, 

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and (iii) covering such other matters relating to this TRR Agreement
and the Transactions as the Administrative Agent shall reasonably request, and
the Company hereby instructs such General Counsel to deliver such opinions.

      (c) All legal matters incident to this TRR Agreement, the New Credit
Agreement and the borrowings and extensions of credit hereunder shall be
satisfactory to the Lenders and to Cravath, Swaine & Moore, counsel for the
Administrative Agent.

      (d) The Administrative Agent shall have received on the date hereof (i) a
copy of the certificate or articles of incorporation, including all amendments
thereto, of the Company, certified as of a recent date by the Secretary of State
of the state of its organization, and a certificate as to the good standing of
the Company as of a recent date, from such Secretary of State; (ii) a
certificate of the Secretary or Assistant Secretary of the Company dated the
date hereof and certifying (A) that attached thereto is a true and complete copy
of the by-laws of the Company as in effect on the date hereof and at all times
since a date prior to the date of the resolutions described in clause (B) below,
(B) that attached thereto is a true and complete copy of resolutions duly
adopted by the Board of Directors of the Company authorizing this TRR Agreement
and the execution, delivery and performance of this TRR Agreement and the
borrowings under the New Credit Agreement, and that such resolutions have not
been modified, rescinded or amended and are in full force and effect, (C) that
the certificate or articles of incorporation of the Company have not been
amended since the date of the last amendment thereto shown on the certificate of
good standing furnished pursuant to clause (i) above, and (D) as to the
incumbency and specimen signature of each officer executing this TRR Agreement
or any other document delivered in connection herewith on behalf of the Company;
(iii) a certificate of another officer as to the incumbency and specimen
signature of the Secretary or Assistant Secretary executing the certificate
pursuant to (ii) above; and (iv) such other documents as the Lenders or Cravath,
Swaine & Moore, counsel for the Administrative Agent, may reasonably request.

      (e) The Administrative Agent shall have received a certificate, dated the
date hereof and signed by a Financial Officer of the Company, confirming
compliance with the conditions precedent set forth in paragraphs (b) and (c) of
Section 2.

         (f) The Administrative Agent shall have received all Fees and other
amounts due and payable on or prior to the 

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date hereof, including, to the extent invoiced, reimbursement or payment of all
out-of-pocket expenses required to be reimbursed or paid by the Company
hereunder.

       SECTION 4. APPLICABLE LAW. THIS TRR AGREEMENT SHALL BE CONSTRUED IN
ACCORDANCE WITH AND GOVERNED BY THE LAWS OF THE STATE OF NEW YORK.

       SECTION 5. ORIGINAL CREDIT AGREEMENT. Until the occurrence of the
Effective Date as provided in Section 3 hereof, the Original Credit Agreement
shall continue in full force and effect in accordance with the provisions
thereof and the rights and obligations of the parties thereto shall not be
affected hereby, and all Fees and interest accruing under the Old Credit
Agreement shall continue to accrue at the rates provided for therein.

       SECTION 6. COUNTERPARTS. This TRR Agreement may be executed in two or
more counterparts, each of which shall constitute an original but all of which
when taken together shall constitute but one contract.

       SECTION 7. EXPENSES. The Company agrees to reimburse the Administrative
Agent for its out-of-pocket expenses in connection with this TRR Agreement
including the reasonable fees, charges and disbursements of Cravath, Swaine &
Moore, counsel for the Administrative Agent.

         IN WITNESS WHEREOF, the parties hereto have caused this TRR Agreement
to be duly executed by their respective authorized officers as of the day and
year first written above.


                                      EG&G, INC,

                                      by
                                      /s/ Daniel T. Heaney
                                      ---------------------
                                      Name:  Daniel T. Heaney
                                      Title: Treasurer


                                      THE CHASE MANHATTAN BANK, 
                                      individually and as
                                      Administrative Agent,

                                      by
                                      /s/ Carol A. Ulmer
                                      -----------------------
                                      Name:  Carol A. Ulmer
                                      Title: Vice President


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                                      BANKBOSTON, N.A.,


                                      by
                                      /s/ Harvey H. Thayer
                                      -------------------------------
                                      Name:  Harvey H. Thayer
                                      Title: Director


                                      DRESDNER BANK AG, NEW YORK 
                                      and Grand Cayman Branches

                                      by
                                      /s/ Anthony J. Berti
                                      -------------------------------
                                      Name:  Anthony J. Berti
                                      Title: Assistant Treasurer

                                      by
                                      /s/ B. Craig Erickson
                                      -------------------------------
                                      Name:  B. Craig Erickson
                                      Title: Vice President


                                      THE FIRST NATIONAL BANK OF
                                      CHICAGO,

                                      by
                                      /s/ Paul Chao
                                      -------------------------------
                                      Name:  Paul Chao
                                      Title: Vice President


                                      THE NORTHERN TRUST COMPANY,

                                      by
                                      /s/ James F. McArdle
                                      -------------------------------
                                      Name:  James F. McArdle
                                      Title: Vice President


                                      ROYAL BANK OF CANADA,

                                      by
                                      /s/ Charles Romano
                                      -------------------------------
                                      Name:  Charles Romano
                                      Title: Manager


                                      SOCIETE GENERALE

                                      by
                                      /s/ Michelle Martin
                                      -------------------------------
                                      Name:  Michelle Martin
                                      Title: Assistant Vice President

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                                      STANDARD CHARTERED BANK,

                                      by
                                      /s/ Kristina McDavid
                                      ----------------------------
                                      Name:  Kristina McDavid
                                      Title: Vice President

                                      by
                                      /s/ David D. Cutting
                                      ----------------------------
                                      Name:  David D. Cutting
                                      Title: Senior Vice President


                                      WACHOVIA BANK, N.A.

                                      by
                                      /s/ John P. Rafterty
                                      ----------------------------
                                      Name:  John P. Rafterty
                                      Title: Senior Vice President




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                                  SCHEDULE 2.01




         LENDERS                                      COMMITMENT

                                                          
         The Chase Manhattan Bank                    $16,000,000
         BankBoston, N.A.                            $10,500,000
         Dresdner Kleinwort Benson                   $10,500,000
         The First National Bank of Chicago          $10,500,000
         The Northern Trust Company                  $10,500,000
         Royal Bank of Canada                        $10,500,000
         Societe Generale                            $10,500,000
         Standard Chartered Bank                     $10,500,000
         Wachovia Bank, N.A.                         $10,500,000