<PAGE>   1
                                                                    EXHIBIT 10.1

                            SECOND AMENDMENT TO LEASE


         THIS SECOND AMENDMENT TO LEASE (the "SECOND AMENDMENT") is made as of
April 28, 2000 between MANOR PARKWAY LLC, a Minnesota limited liability company
("LANDLORD"), and HADCO CORPORATION, a Massachusetts corporation ("TENANT").

                                    RECITALS:

         A. Tenant occupies certain premises in the building (the "BUILDING")
located at 12B Manor Parkway, Salem, New Hampshire under that certain Lease
dated November 1, 1995 (the "ORIGINAL LEASE") between Equity Property Associates
I, a New Hampshire limited partnership ("PRIOR LANDLORD"), as landlord, and
Tenant, as Tenant. The original Lease has been amended by that certain Amendment
to Lease dated May 29, 1998 (the "FIRST AMENDMENT") between Prior Landlord and
Tenant. The Original Lease, as amended by the First Amendment, is the "PRIOR
LEASE". All capitalized terms not otherwise defined in this Second Amendment
shall have the meanings specified in the Prior Lease. The Prior Lease, as
amended by this Second Amendment, is the "LEASE".

         B. Landlord has purchased the Building and has succeeded to all right,
title and interest of Prior Landlord, in, to and under the Prior Lease.

         C. The premises originally leased under the Original Lease consist of
approximately 5,376 rentable square feet of space (the "ORIGINAL PREMISES") in
the Building. The First Amendment added to the Original Premises an additional
1,081 square feet of space in the Building (the "FIRST EXPANSION PREMISES"). The
Original Premises, together with the First Expansion Premises, are the "PRIOR
PREMISES".

         D. Under the Original Lease, the initial Term (the "INITIAL TERM") was
scheduled to expire on October 31, 2000. The First Amendment extended the
expiration date of the Initial Term to May 31, 2003, and granted Tenant two
options to renew the Term, (the "RENEWAL OPTIONS").

         E. Landlord and Tenant have agreed, according to the terms of this
Second Amendment, to: (i) add to the Prior Premises that certain additional
space in the Building (the "SECOND EXPANSION PREMISES") which contains
approximately 4,947 rentable square feet, and which is depicted on the EXHIBIT A
attached to this Second Amendment; and (ii) renew the Term for the ten-year
"First Renewal Term", as that term is defined below in Section 3 of this Second
Amendment.

         NOW THEREFORE, the parties agree as follows:

         1. INTERPRETATION. The Prior Lease, as amended by this Second
Amendment, remains in full force and effect. In the event of a conflict between
the terms of the Prior Lease and this Second Amendment, this Second Amendment
shall control.


<PAGE>   2

         2. EXPANSION OF PREMISES. Effective May 1, 2000, the Second Expansion
Premises shall become part of the premises leased under the Lease for the
remainder of the Term, and each reference in the Lease to the "Premises" shall
be a collective reference to the Original Premises, the First Expansion
Premises, and the Second Expansion Premises. Tenant agrees that on and after May
1, 2000 the Premises shall be conclusively deemed, for all purposes related to
the Lease, to contain 11,404 rentable square feet. Tenant acknowledges that,
prior to the date of this Second Amendment, it has inspected the Second
Expansion Premises and has accepted possession of the Second Expansion Premises
in their "As-Is" condition without any objection or claim whatsoever relating to
the condition of the Second Expansion Premises. Tenant's occupancy of the Second
Expansion Premises prior to the date of this Second Amendment and through April
30, 2000 have been and shall continue to be subject to the terms of the Lease,
with the same effect as if the Second Expansion Premises were part of the
"Premises" throughout such period, except that Tenant shall not be obligated to
pay Annual Fixed Rent or Operating Costs or Tax Expenses with respect to the
Second Expansion Premises for the period prior to May 1, 2000.

         3. RENEWAL OF TERM. The Prior Lease is hereby amended so that the
Initial Term will expire on April 30, 2000, and the Term is hereby renewed for
the period (the "FIRST RENEWAL TERM") from May 1, 2000 through April 30, 2010.
The renewal of the Term for the First Renewal Term shall be deemed to be
Tenant's exercise of both Renewal Options, and Tenant shall have no further
right to renew or extend the Term beyond the First Renewal Term, whether under
the Exhibit D to the First Amendment, or otherwise.

         4. RENT.

                  a. ANNUAL FIXED RENT. Each 12-month period during the Term
         commencing on May 1 shall be a "FIRST RENEWAL TERM LEASE YEAR".
         Effective on and after May 1, 2000, Tenant shall pay Annual Fixed Rent
         in accordance with the following schedule:

<TABLE>
<CAPTION>
------------------------------------- ----------------------------------- -----------------------------------
         FIRST RENEWAL TERM                   ANNUAL FIXED RENT                MONTHLY INSTALLMENTS OF
             LEASE YEAR                                                           ANNUAL FIXED RENT
=============================================================================================================
<S>                                               <C>                                 <C>
                 1                               $ 92,372.40                          $7,697.70
------------------------------------- ----------------------------------- -----------------------------------
                 2                               $ 94,219.85                          $7,851.65
------------------------------------- ----------------------------------- -----------------------------------
                 3                               $ 96,104.25                          $8,008.69
------------------------------------- ----------------------------------- -----------------------------------
                 4                               $ 98,026.33                          $8,168.86
------------------------------------- ----------------------------------- -----------------------------------
                 5                               $ 99,986.86                          $8,332.24
------------------------------------- ----------------------------------- -----------------------------------
                 6                               $101,986.59                          $8,498.88
------------------------------------- ----------------------------------- -----------------------------------
                 7                               $104,026.33                          $8,668.86
------------------------------------- ----------------------------------- -----------------------------------
                 8                               $106,106.85                          $8,842.24
------------------------------------- ----------------------------------- -----------------------------------
                 9                               $108,228.99                          $9,019.08
------------------------------------- ----------------------------------- -----------------------------------
                 10                              $110,393.57                          $9,199.46
------------------------------------- ----------------------------------- -----------------------------------
</TABLE>

<PAGE>   3

                  b. OPERATING COSTS AND TAX EXPENSES. Notwithstanding that,
         under the Prior Lease, Annual Fixed Rent included a specified "Included
         Operating Expense Share" and an "Included Tax Expense Share", Annual
         Fixed Rent on and after May 1, 2000 shall be entirely net of all
         Operating Expenses and Tax Expenses. Effective on and after May 1,
         2000, Tenant shall pay to Landlord, together with each monthly
         installment of Annual Fixed Rent, one-twelfth of the full amount of
         Tenant's Share of Landlord's estimate of Operating Costs and Landlord's
         Tax Expenses for the current calendar year. Effective on and after may
         1, 2000, Tenant's Share of Operating Expenses and Landlord's Tax
         Expenses shall be 38.01%.

         5. ALLOWANCE FOR TENANT WORK. Prior to the date of this Second
Amendment, Tenant has performed certain tenant improvement work (the "TENANT
WORK") in the Second Expansion Premises. Landlord shall reimburse Tenant for all
or some portion of the total cost to Tenant of all labor, materials, and
services supplied in the construction or installment of the Tenant Work,
together with all design costs and other fees and expenses properly allocable to
the performance of the Tenant Work (Collectively, the "PROJECTS COSTS") through
an allowance (the "ALLOWANCE") in an amount of up to $100,000.00. Provided that
no default then exists with respect to Tenant's obligation to pay any rent and
Tenant is then lawfully in occupancy of the Second Expansion Premises in the
routine conduct of its business, Landlord shall pay to Tenant a sum in the
amount of the lower of the $100,000.00 or the actual Project Costs within 10
business days after the last to occur of the following: (i) Landlord's building
manager's receipt and approval of a statement from Tenant's architect or general
contractor (the "SUBSTANTIAL COMPLETION CERTIFICATE") certifying that
substantial completion of the Tenant Work has occurred; (ii) Tenant has
delivered to Landlord a certificate of occupancy from TOWN OF SALEM for the
Second Expansion Premises; (iii) Landlord has received full lien waivers for all
of the Tenant Work; and (iv) Tenant has submitted to Landlord a written request
for payment of the Allowance. Tenant shall be solely responsible for all Project
Costs for the Second Expansion Premises in excess of the Allowance. Project
Costs shall not include, and the Allowance shall not be payable with respect to,
any overhead or other "internal" costs or expenses of Tenant, any costs or
expenses which are not actually paid to third parties unaffiliated with Tenant,
or any costs of purchasing, leasing, and/or installing any equipment or other
personal property which will not become part of the Second Expansion Premises
and the property of Landlord upon installation in the Second Expansion Premises.


<PAGE>   4


                THIS Second Amendment is executed as of the date recited above.


                                MANOR PARKWAY LLC, a Minnesota limited
                                liability company

                                By: ERP Manor Parkway LLC, a Minnesota limited
                                    liability company, its Chief Manager

                                    By:  /s/ Authorized Signatory
                                        --------------------------------------
                                    Its:
                                        --------------------------------------



                                HADCO CORPORATION, a Massachusetts corporation

                                By: /s/ Patricia Randall
                                    ------------------------------------------
                                Its: Vice President and General Counsel
                                    ------------------------------------------