Exhibit (10)(a)(xi)

                              AMENDED AND RESTATED
                               GUARANTY AGREEMENT

            THIS AMENDED AND RESTATED GUARANTY AGREEMENT dated as of October 30,
1996 ("Guaranty") and made by Allied Digital Technologies Corp., a Delaware
corporation, with an office located at 15 Gilpin Avenue, Hauppauge, New York
11788 (the "Guarantor"), in favor of American National Bank and Trust Company of
Chicago, with an office at 33 North LaSalle Street, Chicago, Illinois 60690
(together with its successors and assigns, the "Lender").

                              W I T N E S S E T H:

            A. The Guarantor entered into that certain Guaranty Agreement dated
as of January 11, 1995 in favor of the Lender (the "Original Guaranty").

            B. Hauppauge Record Manufacturing Ltd., a New York corporation (the
"Borrower"), has entered into that certain Amended and Restated Loan and
Security Agreement dated as of October 30, 1996 with the Lender (such agreement,
as it may hereafter be amended or otherwise modified from time to time, being
hereinafter referred to as the "Loan Agreement"; capitalized terms used but not
otherwise defined herein are used herein as defined in the Loan Agreement).

            C. Borrower is an indirect wholly-owned Subsidiary of the Guarantor
and, as a result of the intercorporate and other relationships between the
Guarantor and the Borrower, the Guarantor will benefit from the advances and
financial accommodations provided by the Lender and the Loan Agreement.

            D. As a condition precedent to the effectiveness of the Loan
Agreement and any extensions of credit pursuant thereto, the Lender has
required, among other things, that the Guarantor amend and restate the Original
Guaranty in the form of this Guaranty.

            NOW, THEREFORE, in consideration of the above premises and any loans
and other financial accommodations heretofore, now or hereafter made to or for
the benefit of Borrower by the Lender, and for other good and valuable
consideration, the receipt and sufficiency of which are hereby acknowledged, the
Guarantor hereby agrees


<PAGE>

that, effective as of the Effective Time, the Original Guaranty is amended and
restated as follows:

            1. Guaranty.

            A. The Guarantor hereby absolutely, unconditionally and irrevocably
guarantees the full and prompt payment when due, whether at maturity or earlier,
by reason of acceleration, mandatory prepayment or otherwise, and at all times
thereafter, and the due and punctual performance, of all of the Liabilities
(including without limitation any and all "Liabilities" as such term was defined
in the Hauppauge LSA or the AFL LSA), including, without limitation, all sums
which may become due under the terms and provisions of the Notes or the Loan
Agreement, whether for principal, interest (including, without limitation,
interest accruing before, during or after any bankruptcy, insolvency,
reorganization, arrangement, readjustment of debt, liquidation or dissolution
proceeding, and, if interest ceases to accrue by operation of law by reason of
any such proceeding, interest which otherwise would have accrued in the absence
of such proceeding), premium, fees, expenses or otherwise, whether or not from
time to time reduced or extinguished or hereafter increased or incurred, whether
or not recovery may be or hereafter may become barred by any statute of
limitations, whether enforceable or unenforceable as against the Borrower, now
or hereafter existing, or due or to become due (all Liabilities together with
the Costs (as hereinafter defined), collectively, the "Guaranteed Obligations").
This is a continuing guaranty of payment and not of collection.

            B. The Guarantor further agrees to pay, upon demand, all costs and
expenses ("Costs"), including, without limitation, all court costs and
reasonable attorneys' and paralegals' fees and expenses, paid or incurred by the
Lender (i) in endeavoring to collect all or any part of the Guaranteed
Obligations from, or in prosecuting any action against, the Guarantor or any
other guarantor of all or any part of the Guaranteed Obligations or (ii) in
endeavoring to realize upon (whether by judicial, non-judicial or other
proceedings) any collateral securing the Guarantor's liabilities under this
Guaranty.

            C. The Guarantor further agrees that, if any payment made by the
Borrower or any other Person is applied to the Guaranteed Obligations and is at
any time annulled, set aside, rescinded, invalidated, declared to be fraudulent
or preferential or otherwise required to be refunded or repaid, or the proceeds
of Collateral or any other security are required to be returned by the Lender to
the Borrower, its estate, trustee, receiver or any other Person, including,
without limitation, the Guarantor, under any bankruptcy law, state or federal
law, common law or equitable cause, then, to the extent of such payment or
repayment, the Guarantor's liability hereunder (and any lien, 


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security interest or other collateral securing such liability) shall be and
remain in full force and effect, as fully as if such payment had never been
made, or, if prior thereto this Guaranty shall have been cancelled or
surrendered (and if any lien, security interest or other collateral securing
Guarantor's liability hereunder shall have been released or terminated by virtue
of such cancellation or surrender), this Guaranty (and such lien, security
interest or other collateral) shall be reinstated in full force and effect, and
such prior cancellation or surrender shall not diminish, release, discharge,
impair or otherwise affect the obligations of the Guarantor in respect of the
amount of such payment (or any lien, security interest or other collateral
securing such obligation).

            2. Representations and Warranties. The Guarantor represents and
warrants that as of the date of the execution of this Guaranty, and continuing
so long as any Guaranteed Obligations remain outstanding, and (even if there
shall be no Guaranteed Obligations outstanding) so long as this Guaranty remains
in effect:

            A. Corporate Existence. The Guarantor and each of its Subsidiaries
is a corporation duly organized and in good standing under the laws of the state
of its incorporation and is duly qualified as a foreign corporation and in good
standing in each state where the nature and extent of the business transacted by
it or the ownership of its assets makes such qualification necessary, except for
those jurisdictions in which the failure so to qualify would not, in the
aggregate, have a material adverse effect on the Guarantor's or such
Subsidiaries financial condition, results of operations or business or the
ability of the Guarantor or any such Subsidiary to perform its obligations under
this Guaranty or under any of the Financing Agreements to which it is a party.

            B. Corporate Authority. As to the Guarantor and each of its
Subsidiaries, the execution and delivery by such Person of this Guaranty and of
each Financing Agreement to which it is a party and the performance of such
Person's obligations hereunder and thereunder: (i) are within the corporate
powers of such Person; (ii) are duly authorized by the Board of Directors of
such Person and, if necessary, the stockholders of such Person; (iii) are not in
contravention of the terms of such Person's Certificate or Articles of
Incorporation, or By-Laws, or of any indenture, or other agreement or
undertaking to which such Person is a party or by which such Person or any of
its property is bound or any judgment, decree or order applicable to such
Person; (iv) do not require any governmental consent, registration or approval;
(v) do not contravene any contractual or governmental restriction binding upon
such Person; and (vi) will not, except as contemplated herein, result in the
imposition of any Lien upon any property of such Person under any existing
indenture, mortgage, deed of


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<PAGE>

trust, loan or credit agreement or other material agreement or instrument to
which such Person is a party or by which it or any of its property may be bound
or affected.

            C. Binding Effect. Each of this Guaranty and all of the Financing
Agreements have been duly executed and delivered by the Guarantor and each of
its Subsidiaries that is a party thereto and constitute the legal, valid and
binding obligations of the Guarantor and each such Subsidiary that is a party
thereto, enforceable against the Guarantor and each of its Subsidiaries that is
a party thereto in accordance with their respective terms.

            3. Waivers; Other Agreements.

            A. The Lender is hereby authorized, without notice to or demand upon
the Guarantor, which notice or demand is expressly waived hereby, and without
discharging or otherwise affecting the obligations of the Guarantor hereunder
(which shall remain absolute and unconditional notwithstanding any such action
or omission to act), from time to time, to:

            (i) supplement, renew, extend, accelerate or otherwise change the
      time for payment of, or other terms relating to, the Guaranteed
      Obligations, or any portion thereof, or otherwise modify, amend or change
      the terms of any promissory note or other agreement, document or
      instrument (including, without limitation, the Loan Agreement and the
      other Financing Agreements) now or hereafter executed by the Borrower and
      delivered to the Lender, including, without limitation, any increase or
      decrease of the principal amount thereof or the rate of interest thereon;

            (ii) waive or otherwise consent to noncompliance with any provision
      of any agreement, document or instrument (including, without limitation,
      the Loan Agreement and the other Financing Agreements) evidencing or in
      respect of the Guaranteed Obligations, or any part thereof, now or
      hereafter executed by the Borrower and delivered to the Lender;

            (iii) accept partial payments on the Guaranteed Obligations;

            (iv) receive, take and hold security or collateral for the payment
      or performance of the Guaranteed Obligations, or any part thereof, or for
      the payment or performance of any guaranties of all or


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<PAGE>

      any part of the Guaranteed Obligations, and exchange, enforce, waive,
      substitute, liquidate, terminate, abandon, fail to perfect, subordinate,
      transfer, otherwise alter and release any such security or collateral;

            (v) apply any and all such security or collateral and direct the
      order or manner of sale thereof as the Lender may determine in its sole
      discretion;

            (vi) settle, release, compromise, collect or otherwise liquidate the
      Guaranteed Obligations, or any part thereof, or accept, substitute,
      release, exchange or otherwise alter, affect or impair any security or
      collateral for the Guaranteed Obligations, or any part thereof, or any
      other guaranty therefor, in any manner;

            (vii) add, release or substitute any one or more other guarantors,
      makers or endorsers of all or any part of the Guaranteed Obligations and
      otherwise deal with the Borrower or any other guarantor, maker or endorser
      as the Lender may elect in its sole discretion;

            (viii) apply any and all payments or recoveries from the Guarantor,
      from the Borrower or from any other guarantor, maker or endorser of all or
      any part of the Guaranteed Obligations to the Guaranteed Obligations in
      such order as the Lender in its sole discretion may determine, whether
      such Guaranteed Obligations are secured or unsecured or guaranteed or not
      guaranteed by others;

            (ix) apply any and all payments or recoveries from the Guarantor or
      any other guarantor, maker or endorser of all or any part of the
      Guaranteed Obligations or sums realized from security furnished by any of
      them upon any of their indebtedness or obligations to the Lender, as the
      Lender in its sole discretion may determine, whether or not such
      indebtedness or obligations relate to the Guaranteed Obligations; and

            (x) refund to Borrower or any Person making any payment (or its
      estate, a trustee or receiver) at any time, at the Lender's sole
      discretion, any payment received by the Lender in respect of any
      Guaranteed Obligations, and payment to the Lender of the amount so
      refunded shall be fully guaranteed hereby even though prior thereto this


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<PAGE>

      Guaranty shall have been cancelled or surrendered (or any lien, security
      interest or other collateral shall have been released or terminated by
      virtue thereof) by the Lender, and such prior cancellation or surrender
      (or release or termination) shall not diminish, release, discharge, impair
      or otherwise affect the obligations of the Guarantor hereunder in respect
      of the amount so refunded (and any lien, security interest or other
      collateral so released or terminated shall be reinstated with respect to
      such obligations).

            B. The Guarantor hereby agrees that its obligations under this
Guaranty are absolute and unconditional and shall not be discharged or otherwise
affected as a result of:

            (i) the invalidity or unenforceability of any security for or other
      guaranty of all or any part of the Guaranteed Obligations or of any
      promissory note or other agreement, document or instrument (including,
      without limitation, the Loan Agreement and the Financing Agreements)
      evidencing or in respect of all or any part of the Guaranteed Obligations,
      or the lack of perfection or continuing perfection or failure of priority
      of any security for all or any part of the Guaranteed Obligations or any
      other guaranty therefor;

            (ii) the absence of any attempt to collect the Guaranteed
      Obligations, or any portion thereof, from the Borrower or any other
      guarantor or other action to enforce the same;

            (iii) any failure by the Lender to acquire, perfect and maintain any
      security interest in, or to preserve any rights to, any security or
      collateral for all or any part of the Guaranteed Obligations or any
      guaranty therefor;

            (iv) any election by the Lender in any proceeding instituted under
      Chapter 11 of Title 11 of the United States Code (11 U.S.C. ss. 101 et
      seq.) (the "Bankruptcy Code");

            (v) any borrowing or grant of a security interest by the Borrower,
      as debtor-in-possession, or extension of credit, under the Bankruptcy
      Code;


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<PAGE>

            (vi) the disallowance, under the Bankruptcy Code, of all or any
      portion of the Lender's claim(s) for repayment of the Guaranteed
      Obligations;

            (vii) any use of cash collateral under the Bankruptcy Code;

            (viii) any agreement or stipulation as to the provision of adequate
      protection in any bankruptcy proceeding;

            (ix) the avoidance of any lien in favor of the Lender for any
      reason;

            (x) any bankruptcy, insolvency, reorganization, arrangement,
      readjustment of debt, liquidation or dissolution proceeding commenced by
      or against the Borrower, the Guarantor or any other guarantor, maker or
      endorser, including without limitation, any discharge of, or bar or stay
      against collecting or accelerating, all or any of the Guaranteed
      Obligations (or any interest thereon) in or as a result of any such
      proceeding;

            (xi) any failure by the Lender to file or enforce a claim against
      the Borrower or its estate in any bankruptcy or insolvency case or
      proceeding;

            (xii) any action taken by the Lender that is authorized by this
      Guaranty;

            (xiii) any election by the Lender under Section 9-501(4) of the
      Uniform Commercial Code as enacted in any relevant jurisdiction as to any
      security for the Guaranteed Obligations or any guaranty of all or any part
      of the Guaranteed Obligations; or

            (xiv) any other circumstance which might otherwise constitute a
      legal or equitable discharge or defense of a guarantor.

            C. Until the Guaranteed Obligations shall have been paid and
performed in full and all of the Financing Agreements shall have been
terminated, the Guarantor shall have no right of subrogation and hereby waives
any right to enforce any remedy which the Lender now has or may hereafter have
against the Borrower or any guarantor of all or any part of the Guaranteed
Obligations, and the Guarantor hereby


                                      -7-


<PAGE>

waives any benefit of, and any right to participate in, any security or
collateral given to the Lender to secure payment or performance of any of the
Guaranteed Obligations or any other liability of the Borrower to the Lender. The
Guarantor further agrees that any and all claims of the Guarantor against the
Borrower or any guarantor of all or any part of the Guaranteed Obligations, or
against any of their respective properties, arising by reason of this Guaranty,
including without limitation by reason of any payment by the Guarantor to the
Lender pursuant to the provisions hereof, shall be subordinate and subject in
right of payment to the prior payment, in full, of all principal and interest,
all reasonable costs of collection (including attorneys' and paralegals' fees)
and payment and performance in full of any other liabilities or obligations to
the Lender by the Borrower, including without limitation the Liabilities, which
may arise either with respect to or on any Financing Agreement or any other
note, instrument, document, item, agreement or other writing heretofore, now or
hereafter delivered to the Lender. The Guarantor further waives:

            (i) any requirements of diligence or promptness on the part of the
      Lender;

            (ii) presentment, demand for payment or performance and protest and
      notice of protest with respect to the Guaranteed Obligations or any
      guaranty with respect thereto;

            (iii) notices (a) of nonperformance, (b) of acceptance of this
      Guaranty, (c) of default in respect of the Guaranteed Obligations, (d) of
      the existence, creation or incurrence of new or additional indebtedness,
      arising either from additional loans extended to the Borrower or
      otherwise, (e) that the principal amount, or any portion thereof, and/or
      any interest on any document or instrument evidencing all or any part of
      the Guaranteed Obligations is due, (f) of any and all proceedings to
      collect from the Borrower, any maker, endorser or any other guarantor of
      all or any part of the Guaranteed Obligations, or from anyone else, and
      (g) of exchange, sale, surrender or other handling of any security or
      collateral given to the Lender to secure payment of the Guaranteed
      Obligations or any guaranty therefor;

            (iv) any right to require the Lender to (a) proceed first against
      the Borrower or any other Person whatsoever, (b) proceed against or
      exhaust any security given to or held by the Lender in connection with the
      Guaranteed Obligations, or (c) pursue any other remedy in the Lender's
      power whatsoever;


                                       -8-


<PAGE>

            (v) any defense arising by reason of (a) any disability or other
      defense of the Borrower, (b) the cessation from any cause whatsoever of
      the liability of the Borrower, (c) any act or omission of the Lender or
      others which directly or indirectly, by operation of law or otherwise,
      results in or aids the discharge or release of the Borrower or any
      security given to or held by the Lender in connection with the Guaranteed
      Obligations;

            (vi) any and all other suretyship defenses under applicable law; and

            (vii) the benefit of any statute of limitations affecting the
      Guaranteed Obligations or the Guarantor's liability hereunder or the
      enforcement hereof.

In connection with the foregoing, the Guarantor covenants that this Guaranty
shall not be discharged, except by complete performance of the obligations
contained herein and the payment and discharge in full of all of the Liabilities
and termination of all Financing Agreements (including without limitation any
commitments with respect to the Liabilities). All waivers granted by the
Guarantor hereunder, shall be unconditional and irrevocable irrespective of
whether the Guaranteed Obligations have been paid in full by the Guarantor or
any other party.

            D. The Guarantor hereby assumes responsibility for keeping itself
informed of the financial condition of the Borrower, of any and all endorsers
and/or other guarantors of all or any part of the Guaranteed Obligations and of
all other circumstances bearing upon the risk of nonpayment and nonperformance
of the Guaranteed Obligations, or any part thereof, and the Guarantor hereby
agrees that the Lender shall not have any duty to advise the Guarantor of
information known to the Lender regarding such condition or any such
circumstances. In the event the Lender, in its sole discretion, undertakes at
any time or from time to time to provide any such information to the Guarantor,
the Lender shall not have any obligation (i) to undertake any investigation,
whether or not a part of its regular business routine, (ii) to disclose any
information which the Lender wishes to maintain confidential or (iii) to make
any other or future disclosures of such information or any other information of
the Guarantor.

            E. The Guarantor shall not take any action which would, directly or
indirectly, result in an Event of Default or Default under the Loan Agreement.


                                       -9-


<PAGE>

            F. The Guarantor shall take such actions as may be required by
Holdings to enable Holdings to fulfill its obligations under the Holdings
Guaranty and shall not take any action or fail to take any action which would
result in a breach or default of the provisions of the Holdings Guaranty which
relate to the Guarantor or its Subsidiaries.

            4. Default; Remedies.

            A. The obligations of the Guarantor hereunder are independent of and
separate from the Guaranteed Obligations and the obligations of any other
guarantor of the Guaranteed Obligations or any other Person. If any of the
Guaranteed Obligations are not paid when due (and the applicable grace period,
if any, under the Loan Agreement has expired), or upon the occurrence and during
the continuance of any Default, the Lender may, at its sole election, proceed
directly and at once, without notice, against the Guarantor to collect and
recover the full amount or any portion of the Guaranteed Obligations, without
first proceeding against the Borrower or any other guarantor of all or part of
the Guaranteed Obligations or any other Person, or against any Collateral or any
other security for the Guaranteed Obligations or the obligations of the
Guarantor or any other guarantor under any guaranty; provided, however, if any
Default specified in subsection 9.1(G), (H), (I) or (J) of the Loan Agreement
shall occur and be continuing, the Guarantor shall, at the option of the Lender,
pay to the Lender, the full amount which would be payable under this Guaranty if
all of the Liabilities were then due and payable.

            B. To secure the full and prompt payment and performance of the
Guaranteed Obligations and the Guarantor's obligations under this Guaranty, the
Guarantor hereby grants to the Lender a right of setoff against and a continuing
security interest in all of the Guarantor's now or hereafter acquired balances,
credits, deposits, accounts, monies and any other property and interests in
property of every kind or description of or in the Guarantor's name now or
hereafter coming into the actual possession, custody or control of the Lender or
any agent or affiliate of the Lender in any way or for any purpose (whether for
safekeeping, deposit, custody, pledge, transmission, collection or otherwise).
At any time after any Default, the Lender may, without notice to the Guarantor
and regardless of the acceptance of any security or collateral for the payment
hereof, appropriate and apply toward the payment of the Guaranteed Obligations
(i) any indebtedness due or to become due from the Lender to the Guarantor and
(ii) any balances, credits, deposits, accounts, monies or other property of or
in the name of the Guarantor at any time held by or coming into the possession,
custody or control of the Lender or any agent or affiliate of the Lender.


                                      -10-


<PAGE>

            C. The Guarantor hereby authorizes and empowers the Lender, in its
sole discretion, without any notice (except notices required by law to the
extent such notice as a matter of law may not be waived) or demand to the
Guarantor whatsoever and without affecting the obligations of the Guarantor
hereunder, to exercise any right or remedy which the Lender may have available
to it, including, but not limited to, foreclosure by one or more judicial or
nonjudicial sales, and to the extent permitted by applicable law, the Guarantor
hereby waives any defense to the recovery by the Lender against the Guarantor of
any deficiency after such action and the Guarantor expressly waives any defense
or benefits that may be derived from statutes and laws relating thereto. No
exercise by the Lender of, and no omission of the Lender to exercise, any power
or authority recognized herein and no impairment or suspension of any right or
remedy of the Lender against the Guarantor, any other guarantor, maker or
endorser or any security shall in any way suspend, discharge, release, exonerate
or otherwise affect any of the Guarantor's obligations hereunder or give to the
Guarantor any right of recourse against the Lender.

            D. The Guarantor consents and agrees that the Lender shall not be
under any obligation to make any demand upon or pursue or exhaust any of its
rights or remedies against the Borrower or any guarantor or any other Person
with respect to the Guaranteed Obligations, or to pursue or exhaust any of its
rights or remedies with respect to any security therefor, or any direct or
indirect guaranty thereof or any security for any such guaranty, or to marshal
any assets in favor of the Guarantor or against or in payment of any or all of
the Guaranteed Obligations or to resort to any security or any such guaranty in
any particular order. All of the Lender's rights and remedies provided for
herein, in the Loan Agreement and the other Financing Agreements or otherwise
available to the Lender under applicable law, shall be cumulative and
non-exclusive to the extent permitted by law. Without limiting the generality of
the foregoing, to the extent permitted by applicable law, the Guarantor hereby
agrees that it will not invoke or utilize any law which might cause delay in or
impede the enforcement of the rights under this Guaranty or any of the Financing
Agreements.

            E. Demand, presentment, protest and notice of nonpayment are hereby
waived by the Guarantor. The Guarantor also waives the benefit of all
valuations, appraisal and exemption laws.

            5. Miscellaneous.

            A. This Guaranty shall be irrevocable. If notwithstanding the
provisions of this Guaranty, the Guarantor is entitled by law to revoke or
terminate this Guaranty 


                                      -11-


<PAGE>

other than as is expressly provided for herein, the Guarantor agrees that this
Guaranty shall continue in full force and effect and any such revocation or
termination shall not become effective until at least thirty (30) days after
written notice of revocation of this Guaranty, specifically referring hereto
(and identifying the effective date (the "Revocation Date") of such revocation
which shall be at least thirty (30) days after the Lender's receipt thereof),
signed by the Guarantor, is given to the Lender and is actually received by the
Lender. Such revocation shall not affect the right and power of the Lender to
enforce rights arising prior to the Revocation Date. If, in reliance on this
Guaranty, the Lender makes loans or takes other action after the revocation by
the Guarantor but prior to the Revocation Date, the rights of the Lender with
respect thereto shall be the same as if such revocation had not occurred.

            B. This Guaranty shall be binding upon the Guarantor and upon its
successors and assigns and shall inure to the benefit of the Lender and its
successors and assigns; all references herein to the Borrower and to the
Guarantor shall be deemed to include their respective successors and assigns and
all references herein to the Lender shall be deemed to include its successors
and assigns. The Borrower's successors and assigns shall include, without
limitation, a receiver, trustee or debtor-in-possession of or for the Borrower.
This Guaranty shall be enforceable by Lender or any of Lender's successors and
assigns and any such successors and assigns shall have the same rights and
benefits as the Lender hereunder. Notwithstanding anything herein to the
contrary, the Guarantor may not assign or otherwise transfer its rights or
obligations under this Guaranty without the prior written consent of the Lender.

            C. All references to the singular shall be deemed to include the
plural where the context so requires. All representations, warranties and
covenants contained herein shall survive the execution and delivery of this
Guaranty, the transfer by Lender of any interest in the Guaranteed Obligations
or under the Financing Agreements, and may be relied upon by any assignee or
successor, regardless of any investigation made at any time by or on behalf of
Lender or any such assignee or successor. The Guarantor acknowledges the
Lender's acceptance hereof and reliance hereon.

            D. No course of dealing and no delay on the part of the Lender in
the exercise of any right or remedy shall operate as a waiver thereof, and no
single or partial exercise by the Lender of any right or remedy shall preclude
any further exercise thereof, nor shall any modification or waiver of any of the
provisions of this Guaranty be binding upon the Lender, except as expressly set
forth in a writing duly signed and delivered by the Lender. The Lender's failure
at any time or times hereafter to require strict performance by the Borrower or
the Guarantor or any other Person of any of the provisions, warranties, terms
and conditions contained in the Loan


                                      -12-


<PAGE>

Agreement, any of the other Financing Agreements or any promissory note,
security agreement, agreement, guaranty, instrument or document now or at any
time or times hereafter executed by the Borrower or the Guarantor or any other
Person and delivered to the Lender shall not waive, affect or diminish any right
of the Lender at any time or times hereafter to demand strict performance
thereof and such right shall not be deemed to have been waived by any act or
knowledge of the Lender, or its agents, officers or employees, unless such
waiver is contained in an instrument in writing signed by an authorized officer
or agent of the Lender and directed to the Borrower or the Guarantor or other
Person, as the case may be, specifying such waiver. All Defaults under the Loan
Agreement and all defaults under this Guaranty shall continue until the same are
waived in a writing directed to the Guarantor in accordance with this paragraph
5.D. No waiver of any default shall operate as a waiver of any other default or
the same default on a future occasion, and no action by the Lender permitted
hereunder shall in any way affect or impair the Lender's rights or the
obligations of the Guarantor under this Guaranty. Any determination by a court
of competent jurisdiction of the amount of any principal and/or interest owing
by the Borrower to the Lender shall be conclusive and binding on the Guarantor
irrespective of whether it was a party to the suit or action in which such
determination was made (unless such determination was made as a result of a
default judgment in a proceeding in which Borrower did not appear).

            E. THIS GUARANTY SHALL BE DEEMED TO HAVE BEEN EXECUTED, AND WAS
DELIVERED AND ACCEPTED IN CHICAGO, ILLINOIS. THIS GUARANTY SHALL BE CONSTRUED IN
ALL RESPECTS IN ACCORDANCE WITH, AND GOVERNED BY, AND ANY DISPUTE BETWEEN THE
PARTIES HERETO ARISING OUT OF, CONNECTED WITH, RELATED TO OR INCIDENTAL TO THE
RELATIONSHIP ESTABLISHED BETWEEN THEM IN CONNECTION WITH THIS GUARANTY AND
WHETHER ARISING IN CONTRACT, TORT, EQUITY OR OTHERWISE, SHALL BE RESOLVED IN
ACCORDANCE WITH, THE INTERNAL LAWS (AS OPPOSED TO THE CONFLICTS OF LAW
PROVISIONS) AND DECISIONS OF THE STATE OF ILLINOIS.

            F. WHENEVER POSSIBLE, EACH PROVISION OF THIS GUARANTY SHALL BE
INTERPRETED IN SUCH A MANNER AS TO BE EFFECTIVE AND VALID UNDER APPLICABLE LAW,
BUT IF ANY PROVISION OF THIS GUARANTY SHALL BE PROHIBITED BY OR INVALID UNDER
APPLICABLE LAW, SUCH PROVISION SHALL BE INEFFECTIVE ONLY TO THE EXTENT OF SUCH
PROHIBITION OR INVALIDITY, WITHOUT INVALIDATING THE 


                                      -13-


<PAGE>

REMAINDER OF SUCH PROVISION OR THE REMAINING PROVISIONS OF THIS GUARANTY.

            G. (i) EXCEPT AS PROVIDED IN SUBPARAGRAPH 5.G(ii) BELOW, THE LENDER
AND THE GUARANTOR AGREE THAT ALL DISPUTES BETWEEN THEM ARISING OUT OF, CONNECTED
WITH, RELATED TO, OR INCIDENTAL TO THE RELATIONSHIP ESTABLISHED BETWEEN THEM IN
CONNECTION WITH THIS GUARANTY AND WHETHER ARISING IN CONTRACT, TORT, EQUITY, OR
OTHERWISE, SHALL BE RESOLVED ONLY BY STATE OR FEDERAL COURTS LOCATED IN COOK
COUNTY, ILLINOIS, BUT THE LENDER AND THE GUARANTOR ACKNOWLEDGE THAT ANY APPEALS
FROM THOSE COURTS MAY HAVE TO BE BY A COURT LOCATED OUTSIDE OF COOK COUNTY,
ILLINOIS. THE GUARANTOR WAIVES IN ALL DISPUTES ANY OBJECTION THAT IT MAY HAVE TO
THE LOCATION OF THE COURT CONSIDERING THE DISPUTE.

            (ii) THE GUARANTOR AGREES THAT THE LENDER SHALL HAVE THE RIGHT TO
PROCEED AGAINST THE GUARANTOR OR ITS PROPERTY ("PROPERTY") IN A COURT IN ANY
LOCATION TO ENABLE THE LENDER TO REALIZE ON ANY SECURITY FOR THE GUARANTEED
OBLIGATIONS OR THE GUARANTOR'S OBLIGATIONS UNDER THIS GUARANTY, OR TO ENFORCE A
JUDGMENT OR OTHER COURT ORDER ENTERED IN FAVOR OF THE LENDER. THE GUARANTOR
AGREES THAT IT WILL NOT ASSERT ANY PERMISSIVE COUNTERCLAIMS IN ANY PROCEEDING
BROUGHT BY THE LENDER TO REALIZE ON THE PROPERTY OR ANY SECURITY FOR THE
GUARANTEED OBLIGATIONS OR THE GUARANTOR'S OBLIGATIONS UNDER THIS GUARANTY, OR TO
ENFORCE A JUDGMENT OR OTHER COURT ORDER IN FAVOR OF THE LENDER. THE GUARANTOR
WAIVES ANY OBJECTION THAT IT MAY HAVE TO THE LOCATION OF THE COURT IN WHICH THE
LENDER HAS COMMENCED A PROCEEDING DESCRIBED IN THIS PARAGRAPH 5.G.

            H. THE GUARANTOR HEREBY WAIVES PERSONAL SERVICE OF ANY AND ALL
PROCESS UPON IT AND IRREVOCABLY APPOINTS CT CORPORATION SYSTEM, 208 SOUTH
LASALLE STREET, CHICAGO, ILLINOIS 60604, ITS REGISTERED AGENT, AS THE
GUARANTOR'S AGENT FOR THE PURPOSE OF ACCEPTING ON BEHALF OF THE GUARANTOR
SERVICE OF PROCESS WITHIN THE STATE OF ILLINOIS (THE "SP AGENT"). LENDER AGREES
TO PROMPTLY FORWARD BY REGISTERED MAIL (NO RETURN RECEIPT REQUIRED) A COPY OF
ANY PROCESS SO SERVED BY IT 


                                      -14-


<PAGE>

UPON THE SP AGENT TO THE GUARANTOR AT ITS ADDRESS SET FORTH IN PARAGRAPH 5.O
BELOW. THE GUARANTOR HEREBY CONSENTS TO SERVICE OF PROCESS AS AFORESAID. THE
GUARANTOR FURTHER IRREVOCABLY CONSENTS TO THE SERVICE OF PROCESS OUT OF THE
COURTS REFERRED TO IN PARAGRAPH 5.G ABOVE IN ANY SUCH ACTION OR PROCEEDING BY
MAILING COPIES OF SUCH SERVICE BY REGISTERED MAIL, POSTAGE PREPAID TO THE
GUARANTOR AT SAID ADDRESS. NOTHING IN THIS GUARANTY SHALL AFFECT THE RIGHT OF
THE LENDER TO SERVE PROCESS IN ANY OTHER MANNER PERMITTED BY LAW. ANY FAILURE TO
RECEIVE SUCH COPY SHALL NOT AFFECT IN ANY WAY THE SERVICE OF SUCH PROCESS.

            I. THE GUARANTOR AND THE LENDER WAIVE ANY RIGHT TO HAVE A JURY
PARTICIPATE IN RESOLVING ANY DISPUTE, WHETHER SOUNDING IN CONTRACT, TORT, OR
OTHERWISE, BETWEEN THE LENDER AND THE GUARANTOR ARISING OUT OF, CONNECTED WITH,
RELATED TO OR INCIDENTAL TO THE RELATIONSHIP ESTABLISHED BETWEEN THEM IN
CONNECTION WITH THIS GUARANTY OR ANY OTHER INSTRUMENT, DOCUMENT OR AGREEMENT
EXECUTED OR DELIVERED IN CONNECTION THEREWITH OR THE TRANSACTIONS RELATED
THERETO. THE GUARANTOR AND THE LENDER HEREBY AGREE AND CONSENT THAT ANY SUCH
CLAIM, DEMAND, ACTION OR CAUSE OF ACTION SHALL BE DECIDED BY COURT TRIAL WITHOUT
A JURY AND THAT EITHER MAY FILE AN ORIGINAL COUNTERPART OR A COPY OF THIS
GUARANTY WITH ANY COURT AS WRITTEN EVIDENCE OF THE CONSENT OF THE OTHER TO THE
WAIVER OF THEIR RIGHT TO TRIAL BY JURY.

            J. THE GUARANTOR WAIVES THE POSTING OF ANY BOND OTHERWISE REQUIRED
OF THE LENDER IN CONNECTION WITH ANY JUDICIAL PROCESS OR PROCEEDING TO OBTAIN
POSSESSION OF, REPLEVY, ATTACH, OR LEVY UPON ANY SECURITY FOR THE GUARANTEED
OBLIGATIONS OR THE GUARANTOR'S OBLIGATIONS UNDER THIS GUARANTY, TO ENFORCE ANY
JUDGMENT OR OTHER COURT ORDER ENTERED IN FAVOR OF THE LENDER, OR TO ENFORCE BY
SPECIFIC PERFORMANCE, TEMPORARY RESTRAINING ORDER, PRELIMINARY OR PERMANENT
INJUNCTION, THIS GUARANTY, OR ANY OF THE OTHER AGREEMENT OR DOCUMENT BETWEEN THE
LENDER AND THE GUARANTOR.


                                      -15-


<PAGE>

            K. This Guaranty contains all the terms and conditions of the
agreement between the Lender and the Guarantor relating to the subject matter
hereof. The terms or provisions of this Guaranty may not be waived, altered,
modified or amended except in a writing duly executed by the party to be charged
thereby.

            L. Neither the Lender nor its affiliates, directors, officers,
agents, attorneys or employees shall be liable to the Guarantor for any action
taken, or omitted to be taken, by it or them or any of them under this Guaranty,
the Loan Agreement or the Financing Agreements or in connection herewith or
therewith.

            M. The Guarantor warrants and agrees that each of the waivers set
forth in this Guaranty are made with full knowledge of their significance and
consequences and that, under the circumstances, the waivers are reasonable. If
any of said waivers are determined to be contrary to any applicable law or
public policy, such waivers shall be effective to the maximum extent permitted
by law. Should any one or more provisions of this Guaranty be determined to be
illegal or unenforceable, all other provisions hereof shall nevertheless remain
effective.

            N. Captions are for convenience only and shall not affect the
meaning of any term or provision of this Guaranty.

            O. Except as otherwise expressly provided herein, any notice
required or desired to be served, given or delivered hereunder shall be in
writing, and shall be deemed to have been validly served, given or delivered (i)
three (3) days after deposit in the United States mails, with proper postage
prepaid, (ii) when sent after receipt of confirmation or answerback if sent by
telecopy, or other similar facsimile transmission, (iii) one (1) Business Day
after deposited with a reputable overnight courier with all charges prepaid, or
(iv) when delivered, if hand-delivered by messenger, all of which shall be
properly addressed to the Person to be notified, as the case may be, and sent to
the address or number indicated as follows:

            (i)   If to the Lender at:

                  American National Bank and
                    Trust Company of Chicago
                  33 North LaSalle Street
                  Chicago, Illinois 60690
                  Attention:  Dennis E. Harrison
                  Telecopy:  312/661-6929
                  Confirmation: 312/661-5707


                                      -16-


<PAGE>

            (ii)  If to the Guarantor at:

                  Allied Digital Technologies Corp.
                  15 Gilpin Avenue
                  Hauppauge, New York  11788
                  Attention:  George Fishman
                  Telecopy:   516/234-0346
                  Confirmation:  516/234-0200

                  with a copy of such notice to:

                  Warshaw Burstein Cohen Schlesinger & Kuh, LLP
                  555 Fifth Avenue
                  New York, New York 10017
                  Attention:  Frederick R. Cummings, Jr., Esq.
                  Telecopy:   212/972-9150
                  Confirmation:  212/984-7807

or to such other address or number as the Guarantor or the Lender designates to
the other in the manner herein prescribed.

            P. The Guarantor acknowledges that any breach by the Guarantor of
any of the provisions of this Guaranty will cause irreparable injury to the
Lender and there is no adequate remedy at law for a breach of the provisions of
this Guaranty. The Guarantor agrees that the Lender will have the immediate
right, upon such breach, to obtain temporary and permanent injunctive relief in
any such case without the necessity of proving actual damages and that the
granting of any such relief shall not preclude the Lender from pursuing any
other available relief or remedies for such breach.

            Q. This Guaranty may be executed and accepted in any number of
counterparts each of which shall be an original with the same effect as if the
signatures thereto and hereto were on the same instrument. The delivery of an
executed counterpart of a signature page or acceptance to this Guaranty by
telecopier shall be effective as delivery of a manually executed counterpart of
this Guaranty.

            R. THE GUARANTOR ACKNOWLEDGES AND REPRESENTS TO THE LENDER THAT IT
HAS BEEN ADVISED BY COUNSEL WITH RESPECT TO THE TRANSACTION GOVERNED BY THIS
GUARANTY AND THE TERMS OF THIS GUARANTY.


                                      -17-


<PAGE>

            S. This Guaranty shall become effective at the Effective Time.

            T. The Original Guaranty is amended and restated in its entirety in
the form hereof as of the effectiveness of this Guaranty; provided, however, any
representations and warranties made by the Guarantor to the Lender shall survive
the execution and delivery hereof.

            IN WITNESS WHEREOF, the Guarantor has made this Guaranty as of the
date first above written.

                                    ALLIED DIGITAL TECHNOLOGIES
                                    CORP.


                                    By:  /s/ George Fishman
                                         ------------------
                                    Title:   Chief Executive Officer
                                          --------------------------



Acknowledged and agreed to in Chicago,
Illinois, as of this 30th day of
October, 1996:

AMERICAN NATIONAL BANK AND
  TRUST COMPANY OF CHICAGO


By: /s/Catherine Saccany
    ---------------------
Title:  Vice President
      -------------------


                                      -18-