<PAGE>
-----------------------------
OMB APPROVAL
UNITED STATES OMB NUMBER 3235-0145
SECURITIES AND EXCHANGE COMMISSION EXPIRES: DECEMBER 31, 1997
WASHINGTON, D.C. 20549 ESTIMATED AVERAGE BURDEN
HOURS PER RESPONSE... 14.90
-----------------------------
SCHEDULE 13G
UNDER THE SECURITIES EXCHANGE ACT OF 1934
(AMENDMENT NO. 1)*
Dynatech Corporation
- -------------------------------------------------------------------------------
(Name of Issuer)
Common Stock
- -------------------------------------------------------------------------------
(Title of Class of Securities)
268138104
--------------------------------
(CUSIP Number)
Check the following box if a fee is being paid with this statement [ ]. (A fee
is not required only if the filing person: (1) has a previous statement on file
reporting beneficial ownership of more than five percent of the class of
securities described in Item 1; and (2) has filed no amendment subsequent
thereto reporting beneficial ownership of five percent or less of such class.)
(See Rule 13d-7).
*The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter the
disclosures provided in a prior cover page.
The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).
SEC 1745 PAGE 1 OF 10 PAGES
<PAGE>
- ------------------- ------------------
CUSIP NO. 268138104 13G PAGE 2 OF 10 PAGES
- ------------------- ------------------
- --------------------------------------------------------------------------------
1 NAME OF REPORTING PERSON
S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
John Hancock Mutual Life Insurance Company
I.R.S. No. 04-1414660
- --------------------------------------------------------------------------------
2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) [ ]
(b) [ ]
N/A
- --------------------------------------------------------------------------------
3 SEC USE ONLY
- --------------------------------------------------------------------------------
4 CITIZENSHIP OR PLACE OF ORGANIZATION
Commonwealth of Massachusetts
- --------------------------------------------------------------------------------
5 SOLE VOTING POWER
NUMBER OF
SHARES -0-
-------------------------------------------------------------
BENEFICIALLY 6 SHARED VOTING POWER
OWNED BY
EACH -0-
-------------------------------------------------------------
REPORTING 7 SOLE DISPOSITIVE POWER
PERSON
WITH -0-
-------------------------------------------------------------
8 SHARED DISPOSITIVE POWER
-0-
- --------------------------------------------------------------------------------
9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
None
- --------------------------------------------------------------------------------
10 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
SHARES*
N/A
- --------------------------------------------------------------------------------
11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
See line 9, above.
- --------------------------------------------------------------------------------
12 TYPE OF REPORTING PERSON*
IC, BD, IA, HC
- --------------------------------------------------------------------------------
*SEE INSTRUCTIONS BEFORE FILLING OUT!
PAGE 2 OF 10 PAGES
<PAGE>
- ------------------- ------------------
CUSIP No. 268138104 13G PAGE 3 OF 10 PAGES
- ------------------- ------------------
- --------------------------------------------------------------------------------
1 NAME OF REPORTING PERSON
S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
John Hancock Subsidiaries, Inc.
I.R.S. No. 04-2687223
- --------------------------------------------------------------------------------
2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) [ ]
(b) [ ]
N/A
- -------------------------------------------------------------------------------
3 SEC USE ONLY
- --------------------------------------------------------------------------------
4 CITIZENSHIP OR PLACE OF ORGANIZATION
Delaware
- --------------------------------------------------------------------------------
NUMBER OF 5 SOLE VOTING POWER
SHARES
-0-
-------------------------------------------------------------
BENEFICIALLY 6 SHARED VOTING POWER
OWNED BY
EACH -0-
-------------------------------------------------------------
REPORTING 7 SOLE DISPOSITIVE POWER
PERSON
WITH -0-
-------------------------------------------------------------
8 SHARED DISPOSITIVE POWER
-0-
- --------------------------------------------------------------------------------
9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
None
- --------------------------------------------------------------------------------
10 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
SHARES*
N/A
- --------------------------------------------------------------------------------
11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
See line 9, above.
- --------------------------------------------------------------------------------
12 TYPE OF REPORTING PERSON*
HC
- --------------------------------------------------------------------------------
*SEE INSTRUCTIONS BEFORE FILLING OUT!
PAGE 3 OF 10 PAGES
<PAGE>
- ------------------- ------------------
CUSIP No. 268138104 13G PAGE 4 OF 10 PAGES
- ------------------- ------------------
- --------------------------------------------------------------------------------
1 NAME OF REPORTING PERSON
S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
John Hancock Asset Management
I.R.S. No. 04-3279774
- --------------------------------------------------------------------------------
2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) [ ]
(b) [ ]
N/A
- -------------------------------------------------------------------------------
3 SEC USE ONLY
- --------------------------------------------------------------------------------
4 CITIZENSHIP OR PLACE OF ORGANIZATION
Commonwealth of Massachusetts
- --------------------------------------------------------------------------------
5 SOLE VOTING POWER
NUMBER OF
SHARES -0-
-------------------------------------------------------------
BENEFICIALLY 6 SHARED VOTING POWER
OWNED BY
EACH -0-
-------------------------------------------------------------
REPORTING 7 SOLE DISPOSITIVE POWER
PERSON
WITH -0-
-------------------------------------------------------------
8 SHARED DISPOSITIVE POWER
-0-
- --------------------------------------------------------------------------------
9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
None
- --------------------------------------------------------------------------------
10 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
SHARES*
N/A
- --------------------------------------------------------------------------------
11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
See line 9, above.
- --------------------------------------------------------------------------------
12 TYPE OF REPORTING PERSON*
HC
- --------------------------------------------------------------------------------
*SEE INSTRUCTIONS BEFORE FILLING OUT!
PAGE 4 OF 10 PAGES
<PAGE>
- ------------------- ------------------
CUSIP No. 268138104 13G PAGE 5 OF 10 PAGES
- ------------------- ------------------
- --------------------------------------------------------------------------------
1 NAME OF REPORTING PERSON
S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
The Berkeley Financial Group
I.R.S. No. 04-3145626
- --------------------------------------------------------------------------------
2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) [ ]
(b) [ ]
N/A
- -------------------------------------------------------------------------------
3 SEC USE ONLY
- --------------------------------------------------------------------------------
4 CITIZENSHIP OR PLACE OF ORGANIZATION
Commonwealth of Massachusetts
- --------------------------------------------------------------------------------
5 SOLE VOTING POWER
NUMBER OF
SHARES -0-
-------------------------------------------------------------
BENEFICIALLY 6 SHARED VOTING POWER
OWNED BY
EACH -0-
-------------------------------------------------------------
REPORTING 7 SOLE DISPOSITIVE POWER
PERSON
WITH -0-
-------------------------------------------------------------
8 SHARED DISPOSITIVE POWER
-0-
- --------------------------------------------------------------------------------
9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
None
- --------------------------------------------------------------------------------
10 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
SHARES*
N/A
- --------------------------------------------------------------------------------
11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
See line 9, above.
- --------------------------------------------------------------------------------
12 TYPE OF REPORTING PERSON*
HC
- --------------------------------------------------------------------------------
*SEE INSTRUCTIONS BEFORE FILLING OUT!
PAGE 5 OF 10 PAGES
<PAGE>
- ------------------- ------------------
CUSIP NO. 268138104 13G PAGE 6 OF 10 PAGES
- ------------------- ------------------
- --------------------------------------------------------------------------------
1 NAME OF REPORTING PERSON
S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
NM Capital Management, Inc.
I.R.S. No. 85-0268885
- --------------------------------------------------------------------------------
2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) [ ]
(b) [ ]
N/A
- -------------------------------------------------------------------------------
3 SEC USE ONLY
- --------------------------------------------------------------------------------
4 CITIZENSHIP OR PLACE OF ORGANIZATION
New Mexico
- --------------------------------------------------------------------------------
5 SOLE VOTING POWER
NUMBER OF
SHARES -0-
-------------------------------------------------------------
BENEFICIALLY 6 SHARED VOTING POWER
OWNED BY
EACH -0-
-------------------------------------------------------------
REPORTING 7 SOLE DISPOSITIVE POWER
PERSON
WITH -0-
-------------------------------------------------------------
8 SHARED DISPOSITIVE POWER
-0-
- --------------------------------------------------------------------------------
9 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
-0-
- --------------------------------------------------------------------------------
10 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
SHARES*
N/A
- --------------------------------------------------------------------------------
11 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9
0.0%
- --------------------------------------------------------------------------------
12 TYPE OF REPORTING PERSON*
IA
- --------------------------------------------------------------------------------
*SEE INSTRUCTIONS BEFORE FILLING OUT!
PAGE 6 OF 10 PAGES
<PAGE>
The original statement shall be signed by each person on whose behalf
the statement is filed or his authorized representative. If the statement is
signed on behalf of a person by his authorized representative other than an
executive officer or general partner of the filing person, evidence of the
representative's authority to sign on behalf of such person shall be filed with
the statement, provided, however, that a power of attorney for this purpose
which is already on file with the Commission may be incorporated by reference.
The name and any title of each person who signs the statement shall be typed or
printed beneath his signature.
Note: Six copies of this statement, including all exhibits, should be filed
with the Commission.
ATTENTION: INTENTIONAL MISSTATEMENTS OR OMISSIONS OF FACT CONSTITUTE
FEDERAL CRIMINAL VIOLATIONS (SEE 18 U.S.C. 1001)
Item 1(a) Name of Issuer:
--------------
Dynatech Corporation
Item 1(b) Address of Issuer's Principal Executive Offices:
-----------------------------------------------
3 New England Executive Park
Burlington, MA 01803
Item 2(a) Name of Person Filing:
---------------------
This filing is made on behalf of John Hancock Mutual Life
Insurance Company ("JHMLICO"), JHMLICO's direct, wholly-owned
subsidiary, John Hancock Subsidiaries, Inc. ("JHSI"), JHSI's
direct, wholly-owned subsidiary, John Hancock Asset Management
("JHAM"), JHAM's direct, wholly-owned subsidiary, The Berkeley
Financial Group ("TBFG") and TBFG's direct, wholly-owned
subsidiary, NM Capital Management, Inc. ("NM").
Item 2(b) Address of the Principal Offices:
--------------------------------
The principal business offices of JHMLICO, JHSI and JHAM are
located at John Hancock Place, P.O. Box 111, Boston, MA 02117.
The principal business offices of TBFG is located at 101
Huntington Avenue, Boston, Massachusetts 02199. The principal
business office of NM is 6501 Americas Parkway, Suite 950,
Albuquerque, NM 87110-5372.
Item 2(c) Citizenship:
-----------
JHMLICO, JHAM and TBFG were organized and exist under the laws
of the Commonwealth of Massachusetts. JHSI was organized and
exists under the laws of the State of Delaware. NM was
organized and exists under the laws of the State of New
Mexico.
Item 2(d) Title of Class of Securities:
----------------------------
Common Stock.
Item 2(e) CUSIP Number:
------------
268138104
Item 3 If the Statement is being filed pursuant to Rule 13d-1(b), or
-------------------------------------------------------------
13d-2(b), check whether the person filing is a:
-----------------------------------------------
JHMLICO: (a) (X) Broker or Dealer registered under (S)15 of
the Act.
(c) (X) Insurance Company as defined in (S)3(a)(19)
of the Act.
(e) (X) Investment Adviser registered under (S)203
of the Investment Advisers Act of 1940.
(g) (X) Parent Holding Company, in accordance with
(S)240.13d-1(b)(ii)(G).
PAGE 7 OF 10 PAGES
<PAGE>
JHSI (g) (X) Parent Holding Company, in accordance with
(S)240.13d-1(b)(ii)(G).
JHAM (g) (X) Parent Holding Company, in accordance with
(S)240.13d-1(b)(ii)(G).
TBFG (g) (X) Parent Holding Company, in accordance with
(S)240.13d-1(b)(ii)(G).
NM (e) (X) Investment Adviser registered under (S)203
of the Investment Advisers Act of 1940.
Item 4 Ownership:
---------
(a) Amount Beneficially Owned: -0-
-------------------------
(b) Percent of Class:
----------------
TBFG - 0.0%
NM - 0.0%
(c) (i) sole power to vote or to direct the vote: -0-
(ii) shared power to vote or to direct the
vote: -0-
(iii) sole power to dispose or to direct the disposition
of: -0-
(iv) shared power to dispose or to direct the disposition
of: -0-
Item 5 Ownership of Five Percent or Less of a Class:
--------------------------------------------
With this filing, the Reporting Persons state that they have
ownership of five percent or less of the class.
Item 6 Ownership of More than Five Percent on Behalf of Another Person:
---------------------------------------------------------------
N/A
Item 7 Identification and Classification of the Subsidiary which Acquired
------------------------------------------------------------------
the Security Being Reported on by the Parent Holding Company:
------------------------------------------------------------
See Items 2(a), 3 and 4.
Item 8 Identification and Classification of Members of the Group:
---------------------------------------------------------
Not applicable.
Item 9 Notice of Dissolution of a Group:
--------------------------------
Not applicable.
Item 10 Certification:
-------------
By signing below the undersigned certifies that, to the best of its
knowledge and belief, the securities referred to above were
acquired in the ordinary course of business and were not acquired
for the purpose of and do not have the effect of changing or
influencing the control of the issuer of such securities and were
not acquired in connection with or as a participant in any
transaction having such purpose or effect.
PAGE 8 OF 10 PAGES
<PAGE>
SIGNATURE
After reasonable inquiry and to the best of its knowledge and belief, each
of the undersigned certifies that the information set forth in this statement is
true, complete and correct.
JOHN HANCOCK MUTUAL LIFE INSURANCE COMPANY
By: /s/ John T. Farady
---------------------------------------
Name: John T. Farady
-------------------------------------
Dated: 2/7/96 Title: Senior Vice President & Treasurer
------------------- ------------------------------------
JOHN HANCOCK SUBSIDIARIES, INC.
By: /s/ John T. Farady
---------------------------------------
Name: John T. Farady
-------------------------------------
Dated: 2/7/96 Title: Treasurer
------------------- ------------------------------------
JOHN HANCOCK ASSET MANAGEMENT
By: /s/ James H. Young
---------------------------------------
Name: James H. Young
-------------------------------------
Dated: 2/7/96 Title: Secretary
------------------- -------------------------------------
THE BERKELEY FINANCIAL GROUP
By: /s/ Susan S. Newton
---------------------------------------
Name: Susan S. Newton
-------------------------------------
Dated: 2/7/96 Title: Vice President
------------------- ------------------------------------
NM CAPITAL MANAGEMENT, INC.
By: /s/ Susan S. Newton
---------------------------------------
Name: Susan S. Newton
-------------------------------------
Dated: 2/7/96 Title: Assistant Secretary
------------------- ------------------------------------
PAGE 9 OF 10 PAGES
<PAGE>
EXHIBIT A
JOINT FILING AGREEMENT
----------------------
John Hancock Mutual Life Insurance Company, John Hancock Subsidiaries,
Inc., John Hancock Asset Management, The Berkeley Financial Group and NM Capital
Management, Inc. agree that the Terminating Schedule 13G, to which this
Agreement is attached, relating to the Common Stock of Dynatech Corporation is
filed on behalf of each of them.
JOHN HANCOCK MUTUAL LIFE INSURANCE COMPANY
By: /s/ John T. Farady
---------------------------------------
Name: John T. Farady
-------------------------------------
Dated: 2/7/96 Title: Senior Vice President & Treasurer
------------------- ------------------------------------
JOHN HANCOCK ASSET MANAGEMENT
By: /s/ James H. Young
---------------------------------------
Name: James H. Young
-------------------------------------
Dated: 2/7/96 Title: Secretary
------------------- ------------------------------------
JOHN HANCOCK SUBSIDIARIES, INC.
By: /s/ John T. Farady
---------------------------------------
Name: John T. Farady
-------------------------------------
Dated: 2/7/96 Title: Treasurer
------------------- ------------------------------------
THE BERKELEY FINANCIAL GROUP
By: /s/ Susan S. Newton
---------------------------------------
Name: Susan S. Newton
-------------------------------------
Dated: 2/7/96 Title: Vice President
------------------- ------------------------------------
NM CAPITAL MANAGEMENT, INC.
By: /s/ Susan S. Newton
---------------------------------------
Name: Susan S. Newton
-------------------------------------
Dated: 2/7/96 Title: Assistant Secretary
------------------- ------------------------------------
PAGE 10 OF 10 PAGES
