[Intentionally Left Blank] - 2 -

Exhibit 10.4.13

March 28, 2007

SMTC Manufacturing Corporation of Canada

Societe de Fabrication SMTC du Canada

635 Hood Road

Markham, Ontario

L3R 4N6

Attention: Jane Todd

Dear Sirs/Mesdames:

Reference is made to a Loan Agreement dated as of June 1, 2004 as amended March 10, 2005, August 17, 2005, June 12, 2006, August 1, 2006 and September 20, 2006 (the “Loan Agreement”) between SMTC Manufacturing Corporation of Canada/Societe de Fabrication SMTC du Canada, as borrower (“Borrower”), and Congress Financial Corporation (Canada), now known as Wachovia Capital Finance Corporation (Canada), as lender (“Lender”). All capitalized terms used in this notice of extension but not defined herein have the meanings given to such terms in the Loan Agreement.

Borrower is hereby given notice that Lender has agreed to extend the Renewal Date of the Loan Agreement to April 15, 2008. All other terms and conditions of the Loan Agreement remain in full force and effect, unamended. Borrowers agree to pay to Lender an early termination fee equal to 0.50% of the Canadian Maximum Credit if the Loan Agreement is terminated prior to October 15, 2007.

The undersigned Borrower hereby acknowledges receipt of the foregoing notice of extension of the Loan Agreement and agree to same.

Dated this 28^th day of March, 2007.

[Intentionally Left Blank]

- 2 -

Each of the undersigned Obligors hereby:

Dated this 28^th day of March, 2007.

- 3 -