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                                                                     EXHIBIT 5.1


                                  June 23, 1998


Hadco Corporation
12A Manor Parkway
Salem, NH  03079


Dear Ladies and Gentlemen:

         We are acting as counsel to Hadco Corporation, a Massachusetts
corporation (the "Company") in connection with the registration on a
Registration Statement on Form S-4 (the "Registration Statement") and the
prospectus forming a part thereof (the "Prospectus") under the Securities Act of
1933, as amended, of $200,000,000 aggregate principal amount of the Company's
9-1/2% Senior Subordinated Notes due 2008 (the "Exchange Notes") and the related
guarantees (the "Guarantees") of certain of the Company's subsidiaries named in
the Registration Statement (the "Guarantors"). The Exchange Notes and the
Guarantees are proposed to be issued under an indenture dated as of May 18, 1998
(the "Indenture") among the Company, the Guarantors and State Street Bank and
Trust Company, as trustee, and the related Registration Rights Agreement (the
"Registration Rights Agreement"), dated May 13, 1998, among the Company, the
Guarantors and the Initial Purchasers (as defined in the Registration Rights
Agreement) in exchange for the Company's 9-1/2% Senior Subordinated Notes due
2008 (the "Original Notes") and related guarantees.

         We have examined such documents, records and matters of law as we have
deemed necessary for purposes of this opinion. We have assumed that the Exchange
Notes and the Guarantees will be executed and delivered as set forth in the
Registration Statement, the Prospectus and the Letter of Transmittal set forth
as an exhibit to the Registration Statement. We have assumed the genuineness of
all signatures and the conformity to original documents of all copies of
documents submitted to us as copies, whether certified or not. We have assumed
the conformity of the certificates for the Exchange Notes and the Guarantees to
the specimens of the certificates, which are included as an exhibit to the
Registration Statement. We have assumed that the Exchange Notes, the Guarantees
and the Indenture have been duly authorized, executed and authenticated in
accordance with the terms of the Indenture by each of the parties thereto. Our
opinions expressed herein with respect to the validly and binding effect the
Exchange Notes and the Guarantees are qualified to the extent that the validity
and binding effect thereof may be limited by (i) applicable bankruptcy,
reorganization, arrangements, insolvency, fraud on creditors, preference,
moratorium or similar laws affecting the enforcement of creditors' rights
generally as at the time in effect and (ii) general principles of equity
(whether considered in a proceeding of law or in equity).
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Hadco Corporation
June 23, 1998
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         We are members only of the bar of the Commonwealth of Massachusetts and
therefore do not hold ourselves out as experts in, and express no opinion as to,
the laws of any other state or jurisdiction other than the Laws of the
Commonwealth of Massachusetts and the federal laws of the United States of
America. The Indenture and the Exchange Notes provide that each is governed by
the laws of the State of New York, without giving effect to the conflict of laws
provisions thereof. We have assumed that the substantive laws of the State of
New York are the same as the substantive laws of the Commonwealth of
Massachusetts. We have also assumed that the choice of law provisions of the
Indenture and the Exchange Notes would be given effect.

         Based upon and subject to the foregoing, we are of the opinion that the
Exchange Notes and the Guarantees, when duly executed and authenticated in
accordance with the terms of the Indenture and delivered in exchange for the
Original Notes as contemplated in the Prospectus, will be valid and binding
obligations of the Company and the Guarantors, respectively.

         We consent to the filing of this opinion as an exhibit to the
Registration Statement and to the reference to us under the caption "Legal
Matters" in the Registration Statement.



                                        Very truly yours,


                                        /s/ Testa, Hurwitz & Thibeault, LLP


                                        TESTA, HURWITZ & THIBEAULT, LLP