Further, all of the miscellaneous provisions contained in Section 8 of the Note

 EXHIBIT 10.4

                SECOND AMENDMENT TO THE SIX AND ONE-HALF PERCENT
                  CONVERTIBLE NEGOTIABLE NOTE DUE JUNE 30, 2001

This Second Amendment (the "Second Amendment") to the Six and One-Half Percent
Convertible Negotiable Note Due on June 30, 2001 (the "Note") is made on
September 10, 1997 by and among US Diagnostic Inc., a Delaware corporation
("USD") and HEICO Corporation ("Payee" or "Holder of Note").

                                    RECITALS

WHEREAS, the Company issued the Note to the Payee, which Note is dated July 1,
1996 and is a portion of the consideration for the purchase of MediTek Health
Corporation from the Payee;

WHEREAS, the Note was modified as of December 24, 1996 in an amendment to Six
and One-Half Percent Convertible Negotiable Note Due June 30, 2001 (the "First
Amendment");

WHEREAS, both the Company and Payee desire to alter the conversion rate and
certain demand and other features of the Note;

NOW, THEREFORE, in consideration of the foregoing and other good and valuable
consideration, the receipt and sufficiency of which are hereby acknowledged, the
Company and the Payee hereby agree as follows:

1. CONVERSION RATE. Section 2(a) of the Note is amended to delete the phrase
"conversion price of $9.25 per share" and inserted in its place, the phrase
"conversion price of $8.50 per share."

2. REQUIRED CONVERSION. Section 3 of the Note, as modified in the First
Amendment, shall be deleted and the following language inserted in its place:

            3. REQUIRED CONVERSION. At any time commencing on the later of
            January 1, 1999 or the date that the shares of common stock into
            which this Note are convertible are registered for resale by the
            holder under the Securities Act of 1933 as amended (such time being
            herein called the "required conversion date"), if the last sale
            price of the common stock averages at least $9.25 per share for the
            ten (10) trading days immediately preceding the required conversion
            date, then upon written notice from the Company given within fifteen
            (15) days following the required conversion date, the Payee shall
            convert this Note at the then applicable conversion rate, provided
            however, that in the event of such Notice being given by the
            Company, the Payee may provide Notice to

            the Company of its election to receive payment in cash of the full
            principal balance of the Note together with any accrued but unpaid
            interest, in lieu of consenting to the conversion.

3. PRE-PAYMENT. Section 4 of the Note, as previously modified in the First
Amendment, is amended to substitute in place of the date December 31, 1997, the
date January 1, 1999.

4. REDEMPTION AT THE OPTION OF HOLDER. Section 5 of the Note is deleted and the
following language shall be inserted in its place:

            5. REDEMPTION AT THE OPTION OF HOLDER. If the shares of the Common
            Stock into which this Note are convertible are not registered for
            resale by the Holder under the Securities Act of 1933 as amended,
            prior to January 1, 1999, Holder shall thereafter have the right to
            require the Company to redeem this Note for cash upon ten (10) days
            written Notice by Holder to the Company at any time prior to the
            date such Registration Statement becomes effective.

5. NO OTHER CHANGES. With the exception of the foregoing, all of the other terms
and provisions of the Note and First Amendment shall remain unchanged. Any
defined terms set forth in this Second Amendment which are not defined herein,
but are defined in the Note, shall have the definitions set forth therein.
Further, all of the miscellaneous provisions contained in Section 8 of the Note
shall apply equally to this Second Amendment.

IN WITNESS WHEREOF, This Second Amendment has been executed and delivered on
   the date first specified above by the duly authorized representatives of the
   Company and Holder.

                                                     US DIAGNOSTIC INC.

                                                     BY:/s/ JOSEPH A. PAUL
                                                       -------------------------
                                                       Joseph A. Paul
                                                       President & Chief
                                                       Executive Officer

                                                     HEICO CORPORATION

                                                     BY:/s/ LAURANS A. MENDELSON
                                                        ------------------------
                                                        Laurans A. Mendelson
                                                        Chairman, President and
                                                        Chief Executive Officer 

Basic Info X:

Name: Further, all of the miscellaneous provisions contained in Section 8 of the Note
Type: of the Note
Date: Sept. 30, 1997
Company: HEICO CORP
State: Florida

Other info:

Date:

  • September 10 , 1997
  • July 1 , 1996
  • December 24 , 1996
  • June 30 , 2001
  • December 31 , 1997
  • January 1 , 1999

Organization:

  • One-Half Percent Convertible Negotiable Note Due
  • US Diagnostic Inc.
  • MediTek Health Corporation

Location:

  • Delaware

Money:

  • $ 8.50
  • $ 9.25

Person:

  • Joseph A. Paul
  • Laurans A. Mendelson Chairman