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                                                                     Exhibit 4.3

                                HADCO CORPORATION

                         NON-QUALIFIED STOCK OPTION PLAN

                                SEPTEMBER 7, 1990

                      AS AMENDED AND RESTATED APRIL 7, 1998

             1. PURPOSE. This Non-Qualified Stock Option Plan (hereinafter, the
"Plan") is intended to promote the interests of Hadco Corporation (hereinafter,
the "Company") by providing an inducement for highly qualified personnel to
enter the employ of the Company and an incentive for valued employees to remain
with the Company and to use their best efforts to promote the Company's
continued success, by means of the offer of an opportunity to acquire or
increase their proprietary interest in the Company through the granting of
options to purchase the Company's stock pursuant to the terms of this Plan. As
used herein, the term "Company" includes any present or future subsidiary and
any successor corporation.

             2. RIGHTS TO BE GRANTED. Under this Plan, options may be granted
that give an optionee the right for a specified time period to purchase a
specified number of shares of common stock, par value $0.05, of the Company. The
option price shall be determined in each instance by the Stock Option Committee,
in accordance with the terms of this Plan.

             3. AVAILABLE SHARES. The total number of shares of common stock,
par value $0.05, of the Company, for which options may be granted shall be One
Million (1,000,000) shares, subject to adjustment in accordance with Paragraph
11 of this


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Plan. Shares subject to the Plan may be either authorized but unissued shares or
shares that were once issued and subsequently reacquired by the Company. If any
options granted under this Plan are surrendered before exercise or lapse without
exercise, in whole or in part, the shares reserved therefor shall revert to the
option pool and shall continue to be available under the Plan.

             4. ADMINISTRATION. The Plan shall be administered by the Stock
Option Committee (hereinafter, the "Committee"), which shall consist of two or
more members appointed by the Board of Directors of the Company. The Board may
at any time and from time to time thereafter appoint additional or substitute
members of the Committee and may fill vacancies on the Committee, however
caused. No member of the Committee shall be eligible to participate in the Plan,
and no person shall be appointed to the Committee who has within one (1) year of
his appointment been eligible to selection as a person to whom stock may be
allocated or to whom stock options or stock appreciation rights may be granted
pursuant to this Plan or any other plan of the Company or any of its affiliates
entitling the participants therein to acquire stock, stock options or stock
appreciation rights of the Company or any of its affiliates. No person shall be
a member of the Committee who is not a Director of the Company.

                       In the event no Committee is appointed, the Board shall
act as the Committee and all references in this Plan to the Committee shall mean
the Board. If a Committee is appointed but under applicable law does not have
authority to undertake any


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duty stated herein, the Board shall act as and for the Committee for the purpose
of undertaking that particular duty.

                       The Committee shall choose one of its members as Chair
and shall hold meetings at such times and places as it deems advisable. A
majority of the members of the Committee shall constitute a quorum, and any
action may be taken by a majority of those present and voting at any meeting.

                       Subject to the provisions of this Plan, the Committee
shall have authority in its discretion to determine the employees of the Company
to whom options shall be granted, the number of shares to be covered by each
option, the time or times at which options shall be granted, the purchase price
of the stock covered by each option, the time or times during the term of option
(defined in Section 9) at which each such option shall become exercisable, the
form of agreement to be used in granting the options, and shall further have the
authority to interpret this Plan, and to prescribe, amend and rescind rules and
regulations relating to it. All questions of interpretation and application of
this Plan and of any options issued under it shall be determined by the
Committee, and such determination shall be final and binding upon all persons.

                       No member of the Board or of the Committee shall be
liable for any action or determination made in good faith with respect to the
Plan or any option granted under it.

             5. GRANT OF OPTIONS. The Committee may from time to time grant
options to eligible persons pursuant to the provi- sions of this Plan. Each
option so granted shall be evidenced by


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an Option Agreement, in such form as may be approved by the Committee, which
Agreement shall be duly executed and delivered on behalf of the Company and by
the optionee to whom such option is granted. The Agreement may contain such
terms, provisions, and conditions not inconsistent with the Plan as may be
determined by the Committee, including restrictions to be imposed on the shares
acquired by a participant upon the exercise of an option granted to him.

                       The grant of an option under this Plan shall be effective
as of the date of the vote of the Stock Option Com- mittee of the Board of
Directors of the Company to issue such an option. The granting of options under
this Plan shall be entirely discretionary and nothing in this Plan shall be
deemed to give any employee any right to participate in this Plan or to receive
options.

                       The grant of an option under this Plan confers no right
upon the optionee with respect to the continuation of his employment with the
Company or a subsidiary of the Company. Nothing contained in this Plan or any
option agreement issued hereunder shall be construed as interfering with or
restricting the right of the Company or its subsidiary or the optionee to
terminate his employment at any time.

             6. ELIGIBILITY AND LIMITATIONS. Options may be granted pursuant to
this Plan only to employees of the Company or of any present or future
subsidiary corporation; provided, however, that a person shall be considered to
be an employee within the meaning of this Plan if the person has executed a
written employment


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agreement with the Company which provides for the start of active employment
within one (1) month of the date of grant of an option. In determining the
eligibility of an individual to be granted an option, as well as in determining-
the number of shares to be optioned to any individual, the Committee shall
consider the responsibilities of the person being considered, the nature and
value to the Company or its subsidiaries of his service and accomplishments, his
present and potential contribution to the success of the Company or its
subsidiaries, and such other factors as the Committee may deem relevant.

                       No option may be granted under this Plan after December
31, 2000.

             7. OPTION PRICE. The purchase price of the stock covered by an
option granted pursuant to this Plan shall be the fair market value of the
underlying shares of Common Stock on the date the option is granted.

                       If the Company's common stock is actively traded in the
established over-the-counter market, the fair market value of such common stock
shall be the mean between the bid and asked prices quoted in such
over-the-counter market at the close on the date nearest preceding the date of
grant. If such common stock is listed on any national exchange, or traded in the
Nasdaq National Market, the mean between the high and low sale prices quoted on
such exchange or market on the trading day nearest preceding the date of the
granting of the option may be taken as such fair market value. If the stock is
not publicly traded, the fair market value shall be determined from time to time
by the


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Board of Directors.

                       The full purchase price per share (determined after any
appropriate adjustment has been made under the terms of Section 11 of this Plan)
shall be paid as provided in Section 8 below.

             8. EXERCISE OF OPTION. Subject to the terms and conditions of this
Plan and the Option Agreement, an option granted hereunder shall be exercisable
in whole or in part by giving written notice to the Company by mail or in person
addressed to Treasurer, Hadco Corporation, 12A Manor Parkway, Salem, New
Hampshire 03079, stating the number of shares with respect to which the option
is being exercised, accompanied by payment in full for such shares, which
payment may be made in whole or in part in shares of the common stock of the
Company already owned by the person or persons exercising the option, valued at
fair market value; provided, however, that there shall be no such exercise at
any one time as to fewer than one hundred (100) shares or all of the shares then
purchasable by the person or persons exercising the option, if fewer than one
hundred (100) shares. A copy of such notice shall be provided to Hamilton &
Dahmen, LLP, 73 Tremont Street, Boston, Massachusetts 02108, or to such other
counsel as the Company may hereafter designate, and to the Bank of Boston,
Shareholder Services Division, Post Office Box 644, Boston, Massachusetts 02102,
or to such other Stock Transfer Agent as the Company may hereafter designate.
The Transfer Agent shall, on behalf of the Company, prepare a certificate or
certificates representing such shares acquired


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pursuant to exercise of the option, shall register the optionee as the owner of
such shares on the books of the Company and shall cause the fully executed
certificate(s) representing such shares to be delivered to the optionee as soon
as practicable after payment of the option price in full. The holder of an
option shall not have any rights of a shareholder with respect to the shares
covered by the option, except to the extent that one or more certificates for
such shares shall be delivered to him upon the due exercise of the option.

             Notwithstanding the foregoing provisions, an option granted
hereunder may, to the extent in compliance with applicable law, be exercised by
payment in accordance with a cashless exercise program under which, if so
instructed by the holder of the option, shares of Common Stock may be issued
directly to the broker or dealer of the holder of the option upon receipt by the
Company of the purchase price of the Common Stock covered by such option in cash
or check from the broker or dealer, and except to the extent modified by this
sentence, the exercise will comply with, and be subject to, all the other
provisions of this Section 8.

             9. TERM AND TRANSFERABILITY OF OPTIONS.

             (a) Each option shall become exercisable as provided in each option
granted by the Company to the participant and as provided in each respective
Option Agreement, but in no event shall the option be exercisable during a
period longer than the period beginning with the date of grant and ending not
later than ten (10) years from such date of grant.


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             (b) Any option granted pursuant to this Plan shall not be
assignable or transferable except by will or by the laws of descent and
distribution. During the lifetime of the optionee, any option shall be
exercisable only by the optionee to whom the option is granted. Any option
granted hereunder shall be null and void and without effect upon the bankruptcy
of the optionee to whom the option is granted, or upon any attempted assignment
or transfer, including without limitation, any purported assignment, whether
voluntary or by operation of law, pledge, hypothecation or other disposition,
attachment, trustee process or similar process, whether legal or equitable, upon
such option.

             10. TERMINATION OF OPTION RIGHTS.

             (a) In the event an optionee ceases to be an employee of the
Company for any reason other than death, retirement with the consent of the
Company or disability, any unvested or unexercised options granted to such
optionee shall terminate and become void at midnight on the thirtieth day after
the date of termination, but in no event later than the specified expiration
date of the option.

             (b) In the event that an optionee ceases to be an employee of the
Company by reason of his or her disability or death, any option granted to such
optionee shall be immediately and automatically accelerated and all previously
unexercised options (to the extent that they have not previously been forfeited
in accordance with the terms of the individual option agreement) shall vest and
be exercisable (by the optionee's personal representative, heir or legatee, in
the event of death)


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during the period ending one hundred eighty (180) days after the date of
termination of employment, but in no event later than the specified expiration
date of the option.

             (c) In the event an optionee ceases to be an employee of the
Company by reason of his or her retirement with the consent of the Company, any
option granted to such employee which had vested as of the date of retirement
may be exercised during the period ending ninety (90) days after the date or
retirement, but in no event later than the specified expiration date of the
option.

             (d) For purposes of the Plan, a transfer of an employee between the
parent Company and a subsidiary company, or between subsidiary companies, shall
not be deemed a termination of employment.

             11. ADJUSTMENTS UPON CHANGES IN CAPITALIZATION.

             (a) In the event that the outstanding shares of the Common Stock of
the Company are changed into or exchanged for a different number or kind of
shares or other securities of the Company by reason of any reorganization,
recapitalization, reclassification, stock split-up, combination of shares or
dividends payable in capital stock, appropriate adjustments shall be made in the
number and kind of shares as to which options may be granted under the Plan and
as to which outstanding options or portions thereof then unexercised shall be
exercisable, to the end that the proportionate interest of the option holder
shall be maintained as before the occurrence of such event. Such adjustment in
outstanding options shall be made without change in


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the total price applicable to the unexercised portion of such options and with a
corresponding adjustment in the option price per share.

             (b) Upon any sale of all or substantially all of the assets of the
Company, or upon any merger, consolidation or tender offer in respect of which
the stockholders holding all of the Company's outstanding voting securities
immediately prior to the consummation thereof hold less than 50% of all of the
Company's outstanding voting securities immediately after such consummation
(each of the foregoing sale, merger, consolidation or tender offer hereinafter
called an "Acquisition"), then the date upon which all then outstanding options
granted under this Plan become fully vested and exercisable shall be
automatically accelerated to occur immediately prior to the consummation of such
Acquisition; provided, however, that any such then outstanding options which are
not thereupon exercised in full immediately prior to the consummation of such
Acquisition shall thereupon terminate.

             12. RESTRICTIONS ON ISSUANCE OF SHARES.

Notwithstanding the provisions of Section 8 of the Plan, the Company shall have
no obligation to deliver any certificate or certificates upon exercise of an
option until one of the following conditions shall be satisfied:

                       (i) The shares with respect to which the option has been
             exercised are at the time of the issue of such shares effectively
             registered under applicable Federal and State securities acts as
             now in force or hereafter


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             amended; or

                       (ii) Counsel for the Company shall have given an opinion
             that such shares are exempt from registration under Federal and
             State securities acts as now in force or hereafter amended; and
             until the Company has complied with all applicable laws and
             regulations, including without limitation all regulations required
             by any stock exchange upon which the Company's outstanding common
             stock is then listed.

                       The Company shall use its best efforts to bring about
compliance with the above conditions within a reasonable time, except that the
Company shall be under no obligation to cause a registration statement or a
post-effective amendment to any registration statement to be prepared at its
expense solely for the purpose of covering the issue of shares in respect of
which any option may be exercised.

                       Any stock purchased under the Plan prior to shareholder
approval of the Plan may not be sold, assigned, transferred, pledged or
encumbered in any way and will be held in escrow by the Company until
shareholder approval for the Plan is obtained, and if such approval is not
obtained by the earlier of (i) the next annual meeting of stockholders of the
Company, or (ii) June 30, 1996, the purchase of such stock and any option
granted hereunder and this Plan will be automatically- rescinded and the
purchase price returned to purchasing optionees without interest.

             13. REPRESENTATIONS OF OPTIONEE. The Company may


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require the optionee to deliver such written warranties and representations upon
exercise of the option that the Company deems reasonable or necessary, including
without limitation a representation that a purchase of shares under the option
is made for investment and not with a view to their distribution (as that term
is used in the Securities Act of 1933).

             14. MODIFICATION OF OUTSTANDING OPTIONS. The Commit- tee or the
Board of Directors may accelerate the exercisability of any outstanding option
and may authorize changes to any outstanding option with the consent of the
participant (including, without limitation, to extend the term of an option upon
termination of employment to a date not later than ten (10) years from the
original grant date) when and subject to such conditions as are deemed to be in
the best interests of the Company and in accordance with the purposes of the
Plan.

             15. APPROVAL OF STOCKHOLDERS. The Plan shall be subject to approval
by the affirmative vote of stockholders holding at least a majority of the
voting stock of the Company voting in person or by proxy at or by the earlier of
(i) the next annual meeting of stockholders of the Company, or (ii) June 30,
1991, and the Plan shall take effect as of the date of adoption immediately upon
such approval.

             16. TERMINATION AND AMENDMENT OF PLAN. The Board may at any time
terminate the Plan or make such modification or amendment thereof as it deems
advisable; provided, however, that except as provided in Section 11 the Board
may not, without approval of the stockholders of the Company obtained in the



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manner stated in Section 15, increase the maximum number of shares for which
options may be granted under the Plan. Termination or any modification or
amendment of the Plan shall not, without consent of a participant, affect his
rights under an option previously granted to him.