THE CHASE MANHATTAN BANK

                                 PROMISSORY NOTE




$ 944,171.88                                               Melville, N.Y.
  ----------                                               --------------

                                                           Date: August 3, ,2000

     On November 1, 2000 (insert specific date or "DEMAND"), for value received,
the undersigned  hereby promises to pay to the order of THE CHASE MANHATTAN BANK
(the  "Bank") at its offices at 395 North  Service  Road,  Melville,  N.Y.  Nine
hundred  forty-four  thousand one hundred  seventy-one  and 88/100  DOLLARS with
interest payable on  ______________________  (specific date) and the _______ day
of each ______________ (quarter,  month, etc.) thereafter (and at maturity) at a
per annum rate of 1/2% above the Bank's  Prime Rate (which  shall be the rate of
interest as is publicly  announced at the Bank's  principal  office from time to
time as its  Prime  Rate),  adjusted  as of the date of each  such  change.  The
foregoing  rate shall be computed  for the actual  number of days elapsed on the
basis of a  360-day  year,  but in no event  shall be  higher  than the  maximum
permitted under applicable law. Interest on any past due amount,  whether at the
due date  thereof or by  acceleration,  shall be paid at a rate of four  percent
(4%) per annum in excess of the above stated  rate,  but in no event higher than
the maximum  permitted under  applicable  law. Time for payment  extended by law
shall be included in the computation of interest.

     The undersigned  hereby grants to the Bank a lien on, security  interest in
and right of set-off  against all monies,  securities  and other property of the
undersigned and the proceeds  thereof now or hereafter  delivered to remain with
or in transit in any manner to the Bank, its  correspondents  or its agents from
or for the undersigned, whether for safekeeping,  custody, pledge, transmission,
collection  or for any other  purpose,  or coming  into  possession,  control or
custody of the Bank,  Chase  Securities Inc., or any other affiliate of the Bank
in any way,  and,  also,  any balance of any deposit  account and credits of the
undersigned  with, and any other claims of the  undersigned  against,  the Bank,
Chase  Securities  Inc., or any other affiliate of the Bank at any time existing
(all of which are collectively called the "Collateral"),  as collateral security
for the payment of this note and all other  liabilities  and  obligations now or
hereafter owed by the  undersigned to the Bank,  contracted  with or acquired by
the Bank,  whether  joint,  several,  direct,  indirect,  absolute,  contingent,
secured,   unsecured,   matured  or  unmatured   (all  of  which  are  hereafter
collectively called  "Liabilities"),  hereby authorizing the Bank at any time or
times,  without notice or demand,  to apply any such  Collateral or any proceeds
thereof to any of such  Liabilities in such amounts as it in its sole discretion
may select,  either  contingent,  unmatured or  otherwise  and whether any other
collateral security therefor is deemed adequate or not.  Undersigned  authorizes
the Bank to deliver to others a copy of this note as written notification of the
undersigned's  transfer  of a  security  interest  in the  Collateral.  The Bank
further  is  authorized  at any time or times,  without  demand or notice to the
undersigned,  to  transfer to or register in the name of its nominee or nominees
all or any part of the Collateral and to exercise any and all rights,  power and
privileges (except that prior to an Event of Default the Bank shall not have the
right  to vote or to  direct  the  voting  of any  Collateral).  The  collateral
security  and other  rights  described  herein shall be in addition to any other
collateral  security  described  in  any  separate  agreement  executed  by  the
undersigned.

<PAGE>

         In the event of:  default  in the prompt  payment  of any  Liabilities;
default in any other indebtedness of the undersigned (which, for the purposes of
this sentence, means the undersigned or any guarantor, surety or endorser of, or
any person or entity  which has  pledged  any of its  property  to  secure,  any
Liabilities);  complete or partial  liquidation or suspension of any business of
the undersigned;  dissolution,  merger,  consolidation or  reorganization of the
undersigned;  death of or loss of  employment  by an individual or any member of
any partnership (if the undersigned is an individual or a partnership);  failure
to furnish any  financial  information  or to permit  inspection of any books or
records at the Bank's request;  a  representation,  warranty or statement of the
undersigned  proving  false in any  material  respect  when  made or  furnished;
general   assignment   for  the  benefit  of  creditors  or  insolvency  of  the
undersigned;  commencement  of any  proceeding  supplementary  to any  execution
relating to any judgment against the undersigned;  attachment,  distraint, levy,
execution or final judgment  against the  undersigned or against the property of
the  undersigned;  assignment  by the  undersigned  of any  equity in any of the
Collateral  without the written consent of the Bank;  appointment of a receiver,
conservator,  rehabilitator or similar officer for the  undersigned,  or for any
property of the undersigned;  tax assessment by the United States  Government or
any state or political  subdivision thereof against the undersigned;  the taking
of possession of, or assumption of control over, all or any substantial  part of
the property of the undersigned by the United States Government, or any state or
political  subdivision thereof,  foreign government (de facto or de jure) or any
agency of any thereof;  calling of a meeting of  creditors,  assignment  for the
benefit of creditors or bulk sale or notice thereof; any mortgage,  pledge of or
creation of a security  interest in any assets without the consent of the holder
of this note; filing of a petition in bankruptcy, commencement of any proceeding
under any  bankruptcy  or debtor's  law (or similar law  analogous in purpose or
effect) for the relief, reorganization,  composition,  extension, arrangement or
readjustment of any of the obligations by or against the undersigned;  then, and
in any of those events (each, an "Event of Default"), all Liabilities,  although
otherwise  unmatured  or  contingent,  shall  forthwith  become due and  payable
without notice or demand and notwithstanding  anything to the contrary contained
herein or in any other instrument. Further, acceptance of any payments shall not
waive or affect any prior demand or acceleration of these Liabilities,  and each
such  payment  made shall be applied  first to the payment of accrued  interest,
then to the aggregate unpaid principal or otherwise as determined by the Bank in
its sole  discretion.  The  undersigned  hereby  irrevocably  consents to the in
personam  jurisdiction  of the federal  and/or state courts  located  within the
State of New York over  controversies  arising  from or relating to this note or
the Liabilities and irrevocably  waives trial by jury and the right to interpose
any  counterclaims  or  offset  of  any  nature  in  any  such  litigation.  The
undersigned further irrevocably waives presentment,  demand,  protest, notice of
dishonor and all other  notices or demands of any kind in  connection  with this
note or any Liabilities.  The undersigned  shall be jointly and severally liable
hereon.

<PAGE>

         The Bank may,  at its option,  at any time when in the  judgment of the
Bank the Collateral is inadequate or the Bank deems itself insecure,  or upon or
at any time  after the  occurrence  of an Event of  Default,  proceed to enforce
payment of the same and exercise any of or all the rights and remedies  afforded
the Bank by the Uniform  Commercial Code (the "Code") or otherwise  possessed by
the Bank. Any  requirement of the Code for reasonable  notice to the undersigned
shall be deemed to have been  complied  with if such  notice is mailed,  postage
prepaid,  to the undersigned and such other persons  entitled to notice,  at the
addresses  shown on the  records of the Bank at least four (4) days prior to the
time of sale, disposition or other event requiring notice under the Code.

         The  undersigned  agrees to pay to the Bank,  as soon as incurred,  all
costs and expenses  incidental to the care,  preservation,  processing,  sale or
collection of or  realization  upon any of or all the  Collateral or incurred in
connection  with the  enforcement  or  collection  of this  note,  or in any way
relating to the rights of the Bank  hereunder,  including  reasonable  inside or
outside  counsel  fees and  expenses.  Each and every  right and  remedy  hereby
granted  to the  Bank  or  allowed  to it by law  shall  be  cumulative  and not
exclusive  and each may be  exercised by the Bank from time to time and as often
as may be necessary.  The  undersigned  shall have the sole  responsibility  for
notifying the Bank in writing that the  undersigned  wishes to take advantage of
any  redemption,  conversion  or other  similar right with respect to any of the
Collateral.  The Bank may  release  any  party  (including  any  partner  or any
undersigned)  without  notice to any of the  undersigned,  whether as co-makers,
endorsers,  guarantors,  sureties,  assigns or otherwise,  without affecting the
liability  of any of the  undersigned  hereof or any partner of any  undersigned
hereof.

         Upon any transfer of this note, the  undersigned  hereby waiving notice
of any such transfer, the Bank may deliver the Collateral or any part thereof to
the transferee who shall  thereupon  become vested with all the rights herein or
under  applicable law given to the Bank with respect  thereto and the Bank shall
thereafter  forever be  relieved  and fully  discharged  from any  liability  or
responsibility in the matter;  but the Bank shall retain all rights hereby given
to it with respect to any  Liabilities  and  Collateral not so  transferred.  No
modification  or waiver of any of the provisions of this note shall be effective
unless in writing, signed by the Bank, and only to the extent therein set forth;
nor shall any such waiver be  applicable  except in the  specific  instance  for
which given. This agreement sets forth the entire  understanding of the parties,
and the undersigned  acknowledges that no oral or other agreements,  conditions,
promises,  understandings,  representations or warranties exist in regard to the
obligations hereunder, except those specifically set forth herein.

         If the  undersigned is a partnership,  the agreement  herein  contained
shall  remain  in force  and  applicable,  notwithstanding  any  changes  in the
individuals  composing the partnership or any release of any partner or partners
and their  partners  shall not thereby be released from any  liability.  If this
note is signed by more than one party, the terms "undersigned",  as used herein,
shall include the  "undersigned  and each of them" and each  undertaking  herein
contained shall be their joint and several undertaking,  provided, however, that
in the  phrases  "of  the  undersigned",  "by  the  undersigned",  "against  the
undersigned",   "for  the  undersigned",   "to  the  undersigned"  and  "on  the
undersigned",  the term  "undersigned"  shall  mean the  "undersigned  or any of
them";  and the Bank may release or exchange any of the Collateral  belonging to
any of the parties  hereto and it may renew or extend any of the  liabilities of
any of them and may make  additional  advances or extensions of credit to any of
them or release or fail to set off any deposit  account or credit any of them or
grant other  indulgences to any of them, all from time to time,  before or after
maturity  hereof,  with or without  further  notice to or assent from any of the
other  parties  hereto.  Each  reference  herein to the Bank  shall be deemed to
include its  successors,  endorsees and assigns,  in whose favor the  provisions
hereof  shall also inure.  Each  reference  herein to the  undersigned  shall be
deemed to include the heirs, executors,  administrators,  legal representatives,
successors  and  assigns of the  undersigned,  all of whom shall be bound by the
provisions hereof.

<PAGE>

         The provisions of this note shall be construed and  interpreted and all
rights and obligations  hereunder  determined in accordance with the laws of the
State of New York, and, as to interest rates, applicable Federal law.

                /s/ Vincent DiSpigno
                ---------------------------
Address:         PWR Systems, Inc.
                 3512 Veterans Memorial Hwy
                 Bohemia, NY 11716