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                                                                           10.56

                                       GUARANTY


     THIS GUARANTY dated as of March 31, 1998 is made and delivered by Robert
Bertrand, an individual maintaining an address at 851 Arbolado, Fullerton,
California 92635 ("Guarantor") to and for the benefit of XCEL Arnold Circuits,
Inc., a New Jersey corporation having an address at 4290 E. Brickell Street,
Ontario, California 91761 ("Lender").

     A.   Pursuant to an Asset Purchase Agreement, as amended, dated as of
January 9, 1998 (the "Asset Purchase Agreement"), Lender has agreed to sell to
Arnold Circuits, Inc., a California corporation ("Borrower"), which is a
wholly-owned by Bertrand, certain of its assets (the "Assets").

     B.   A portion of the purchase price of the Assets is being paid by the
Borrower by virtue of the execution of a $650,000.00 Promissory Note in the form
annexed as Exhibit A to the Asset Purchase Agreement (the "Note").

     C.   The Asset Purchase Agreement requires, as a condition and obligation
of Lender to effect the Asset Purchase, that Bertrand execute a guarantee of the
payment of $650,000 by Borrower pursuant to the Note.

     D.   To induce Lender to accept Borrower's Note as partial payment for the
Assets, and for other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, Lender has required and Guarantor
has agreed to guarantee the performance of certain obligations of Borrower as
set forth herein.

     NOW THEREFORE, in consideration of the foregoing premises and intending to
be legally bound hereby, the undersigned agrees as follows:

     1.   OBLIGATIONS GUARANTEED.  For consideration, the adequacy and
sufficiency of which is acknowledged, Guarantor unconditionally guarantees the
payment and performance of Borrower's obligations under the Promissory Note and
the payment of all liabilities of Borrower to Lender, whether absolute or
contingent, matured or unmatured, direct or indirect, similar or dissimilar, due
or to become due arising under the Note (all such payment and performance
obligations are hereinafter referred to as the "Obligations").

     2.   CONTINUING NATURE/REVOCATION/REINSTATEMENT.  This Guaranty is in
addition to any other guaranties of the Obligations, is continuing and covers
all Obligations.  Revocation by one or more signers of this Guaranty or any
other guarantors of the Obligations shall not (a) affect the obligations under
this Guaranty of a non-revoking Guarantor, (b) apply to Obligations outstanding
when Lender receives written notice of revocation, or to any extensions,
renewals, readvances, modifications, amendments or replacements of such
Obligations, or (c) apply to Obligations, arising after Lender receives such
notice of revocation, which are created pursuant to a commitment existing at the
time of the revocation, whether or not there exists an unsatisfied condition to
such commitment or Lender has another defense to its performance.  All of
Lender's rights pursuant to this Guaranty



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continue with respect to amounts previously paid to Lender on account of any
Obligations which are thereafter restored or returned by Lender, whether in
bankruptcy, reorganization, insolvency, receivership or similar proceeding
("Insolvency Proceeding") of Borrower or for any other reason, all as though
such amounts had not been paid to Lender; and Guarantor's liability under this
Guaranty (and all its terms and provisions) shall be reinstated and revived,
notwithstanding any surrender or cancellation of this Guaranty.  Lender, at its
sole discretion, may determine whether any amount paid to it must be restored or
returned; provided, however, that if Lender elects to contest any claim for
return or restoration, Guarantor agrees to indemnify and hold Lender harmless
from and against all cost and expenses, including reasonable attorneys' fees,
expended or incurred by Lender in connection with such contest.  If any
Insolvency Proceeding is commenced by or against Borrower or Guarantor, at
Lender's election, Guarantor's obligations under this Guaranty shall immediately
and without notice or demand become due and payable, whether or not then
otherwise due and payable.

     3.   AUTHORIZATION.  Guarantor authorizes Lender, without notice and
without affecting guarantor's liability under this Guaranty, from time to time,
whether before or after any revocation of this Guaranty, to (a) renew,
compromise, extend, accelerate, release, subordinate, waive, amend and restate,
or otherwise amend or change, the interest rate, time or place for payment or
any other terms of all or any part of the Obligations; (b) accept delinquent or
partial payments on the Obligations; (c) take or not take security or other
credit support for this Guaranty or for all or any part of the Obligations, and
exchange, enforce, waive, release, subordinate, fail to enforce or perfect,
sell, or otherwise dispose of any such security or credit support; (d) apply
proceeds of any such security or credit support and direct the order or manner
of its sale or enforcement as Lender, at its sole discretion, may determine; and
(e) release or substitute Borrower or any guarantor or other person or entity
liable on the Obligations.

     4.   WAIVERS.  To the maximum extent permitted by law, Guarantor waives (a)
all rights to require Lender to proceed against Borrower, or any other
guarantor, or proceed against, enforce or exhaust any security for the
Obligations or to marshall assets or to pursue any other remedy in Lender's
power whatsoever; (b) all defenses arising by reasons of any disability or other
defense of Borrower, the cessation for any reason of the liability of Borrower,
any defense that any other indemnity, guaranty or security was to be obtained,
any claim that Lender has made Guarantor's obligations more burdensome or more
burdensome than Borrower's obligations, and the use of any proceeds of the
Obligations other than as intended or understood by Lender or Guarantor; (c) all
presentments, demands for performance, notices of nonperformance, protests,
notices of protest, notices of dishonor, notices of acceptance of this Guaranty
and of the existence or creation of new or additional Obligations, and all other
notices or demands to which Guarantor might otherwise be entitled; (d) all
conditions precedent to the effectiveness of this Guaranty; (e) all rights to
file a claim in connection with the Obligations in an Insolvency Proceeding
filed by or against Borrower; (f) all rights to require Lender to enforce any of
its remedies; and (g) until the Obligations are satisfied or fully paid with
such payment not subject to return:  (i) all rights of subrogation,
contribution, indemnification or reimbursement, (ii) all rights of recourse to
any assets or property of Borrower, or to any collateral or credit support for
the Obligations, (iii) all rights to participate in or benefit from any security
or credit support Lender may have or acquire, (iv) all rights, remedies and
defenses Guarantor may have or acquire against Borrower and (v) any rights or
defenses Guarantor may have


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by reason of protection afforded to Borrower with respect to the Obligations
pursuant to the laws of California.

     5.   ASSIGNMENTS.  Without notice to Guarantor, Lender may assign the
Obligations and this Guaranty, in whole or in part.

     6.   INTEGRATION/SEVERABILITY/AMENDMENTS.  This Guaranty is intended by
Guarantor and Lender as the complete, final expression of their agreement
concerning its subject matter.  It supersedes all prior understandings or
agreements with respect thereto and may be changed only by a writing signed by
Guarantor and Lender.  No course of dealing, or parol or extrinsic evidence
shall be used to modify or supplement the express terms of this Guaranty.  If
any provision of this Guaranty is found to be illegal, invalid or unenforceable,
such provision shall be enforced to the maximum extent permitted, but if fully
unenforceable, such provision shall be severable, and this Guaranty shall be
construed as if such provision had never been a part of this Guaranty, and the
remaining provisions shall continue in full force and effect.

     7.   JOINT AND SEVERAL.  The obligations of the Guarantor under this
Guaranty is independent of the Obligations and of the obligations of any other
person or entity.  A separate action or actions may be brought and prosecuted
against any one or more Guarantors, whether action is brought against Borrower
or other guarantors of the Obligations, and whether Borrower or others are
joined in any such action.

     8.   GOVERNING LAW.  THIS GUARANTY SHALL BE CONSTRUED IN ALL RESPECTS IN
ACCORDANCE WITH, AND GOVERNED BY, THE LAWS AND DECISIONS OF THE STATE OF
CALIFORNIA.  EACH GUARANTOR HEREBY CONSENTS TO JURISDICTION AND VENUE IN ANY
CONTROVERSY INVOLVING THIS AGREEMENT IN FEDERAL OR STATE COURT SITTING IN THE
STATE OF CALIFORNIA.

WITNESS:


                                        /s/Robert Bertrand
----------------------------            -------------------------
                                        ROBERT BERTRAND


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