EXHIBIT 10.61

                           TRIMBLE NAVIGATION LIMITED


                                 THIRD AMENDMENT


         THIS THIRD AMENDMENT (this  "Amendment") is entered into as of February
16, 1999 by and among  TRIMBLE  NAVIGATION  LIMITED,  a  California  corporation
having  its  chief  executive  office  at  645  North  Mary  Avenue,  Sunnyvale,
California  94086 (the  "Borrower") and FLEET NATIONAL BANK, a national  banking
association  organized  under the laws of the  United  States  and having a head
office at One Federal Street, Boston, Massachusetts 02110, as the Agent and as a
Lender,  BANKBOSTON,  N.A., a national banking association,  organized under the
laws of the  United  States  and  having a head  office at One  Hundred  Federal
Street,  Boston,  Massachusetts 02110, as the Syndication Agent and as a Lender,
SANWA BANK  CALIFORNIA,  a banking  corporation  organized under the laws of the
State of California  and having an office at 220 Almaden  Boulevard,  2nd Floor,
San Jose,  California 95113, as a Lender,  and ABN AMRO BANK N.V., a Netherlands
banking  corporation having an office at 101 California Street,  Suite 4550, San
Francisco,  California 94115, as a Lender,  under the Loan Agreement (as defined
below), to which reference is made for the definitions of all capitalized terms,
used, but not otherwise defined, herein.

                                 R E C I T A L S

         WHEREAS,  the parties have entered  into a Loan  Agreement  dated as of
August 27, 1997 among the Borrower,  the Agent,  the Syndication  Agent, and the
lenders from time to time party thereto (the "Lenders"),  as amended by a Letter
of Amendment  dated  December 17, 1997,  and a Second Letter of Amendment  dated
August  11,  1998 (the  "Agreement"),  pursuant  to which the  Lenders  issued a
Revolving Credit Loan Commitment to the Borrower in the maximum principal amount
of $50,000,000.00;

         WHEREAS, pursuant to a certain Waiver Letter dated October 27, 1998 and
a certain  Supplement  to Loan  Agreement  and  Additional  Waiver  Letter dated
December 9, 1998 (the "December 9, 1998 Supplement"), the Borrower was granted a
limited waiver with respect to the Borrower's  compliance with certain covenants
contained in the Agreement for the Borrower's  fiscal  quarters ended October 2,
1998 and January 1, 1999, conditional upon the satisfaction of certain specified
waiver conditions  contained therein on or prior to February 16, 1999, including
inter alia the  agreement  of the Agent and the  Lenders  to  further  amend the
Agreement in certain respects;

     WHEREAS,  the Agent and the Lenders  have agreed to amend the  Agreement as
hereinafter set forth;

         NOW THEREFORE,  in  consideration  of the mutual benefits to be derived
from the parties' continuing relationship under the Agreement and for other good
and  valuable  consideration,  the  receipt  and  adequacy  of which are  hereby
acknowledged,  the Borrower,  the Agent, the Syndication  Agent, and the Lenders
hereby agree that the Agreement is hereby amended,  effective  February 16, 1999
(the "Effective Date"), as follows:

     1. The following  defined  terms  appearing in Section 1.1 of the Agreement
are hereby amended in their entirety, respectively, to read as follows:

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         "Commitment" means the Lenders' several commitments to make or maintain
the Loans as set forth in Section 2.1 hereof in the maximum  outstanding  amount
of each  Lender's Pro Rata Share of  $50,000,000,  minus,  until the fifth (5th)
Business Day following delivery of the Borrower's quarterly financial statements
pursuant to Section 5.3.3 of the Agreement and the related Officer's Certificate
as required by Section 5.3.4 reflecting Operating Income and Net Income equal to
or greater than one dollar ($1.00), a reserve of $25,000,000, as such amount may
be reduced pursuant to Section 2.6.4.

         "Financing Documents" means,  collectively,  this Agreement, each Note,
the Security  Documents,  the Side Letter, the Post-Closing  Letter, if any, any
Letter of Credit, any Letter of Credit Agreement,  any agreement with any Lender
providing any interest rate  protection  arrangement  and each other  agreement,
instrument  or document  now or  hereafter  executed in  connection  herewith or
therewith.

         "Net Income"  means,  for any fiscal  period,  the net after tax income
(loss) of the Borrower and any Subsidiaries  for such period,  excluding (i) any
extraordinary or other non-recurring  gains, and (ii) any gains from the sale or
disposition  of assets  other than in the ordinary  course of  business,  all as
determined on an accrual and  consolidated  basis in accordance with GAAP, plus,
to the extent included in the  calculation of net income,  any amount taken as a
one-time charge against earnings attributable to (i) the settlement of the class
action  litigation  described in Exhibit A attached hereto,  (ii) the closing of
the Borrower's  commercial marine division,  or (iii) charges resulting from the
reduction  in  Borrower's  employees  resulting  from the  Borrower's  switch to
contract  manufacturing,  provided  that the amount of all such charges added to
net income shall not exceed $2,000,000 in the aggregate.

         "Security  Documents"  means  any and all  documents,  instruments  and
agreements now or hereafter providing security for the Obligations and any other
Indebtedness  of the  Borrower  or any  Subsidiary  to any of the  Lenders,  the
Issuing Lender and/or the Collateral Agent, the Agent or the Syndication  Agent,
including   without   limitation  the  following   documents,   instruments  and
agreements:  any  mortgages  on and  collateral  assignments  of  real  property
interests  (fee,  leasehold  and  easement) of the  Borrower and any  Subsidiary
granting Liens thereon;  landlord lien waivers and consents as may be reasonably
requested by the Collateral  Agent;  security  agreements  granting Liens on all
Borrower's and any  Subsidiary's  fixtures and tangible and intangible  personal
property;  collateral assignments of Borrower's and any Subsidiary's  contracts,
licenses,  permits,  easements and leases;  collateral assignments of Borrower's
and any Subsidiary's  copyrights;  conditional assignments of Borrower's and any
Subsidiary's trademarks and patents; any subordination  agreement;  any software
escrow  agreement;  any  guaranty;  any  pledge  of  the  capital  stock  of any
Subsidiary;  casualty and liability insurance policies providing coverage to the
Collateral  Agent for the benefit of the Lenders;  UCC  financing  statements or
similar filings perfecting the above-referenced security interests,  pledges and
assignments,  all as executed, delivered to and accepted by the Collateral Agent
and as may be required by this Agreement, as any of the foregoing may be amended
from time to time.

         2.  Section  1.1 of the  Agreement  is hereby  further  amended  by the
addition of the following new defined terms to be added alphabetically thereto:

         "Collateral  Agent"  means  Fleet  National  Bank,  in its  capacity as
collateral agent under the Security Documents.

         "Issuing  Lender"  means Fleet  National  Bank,  in its capacity as the
issuer of Letters of Credit hereunder.

         "LC Participant" has the meaning set forth in Section 2.1.1(e).

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         "Letter of Credit" has the meaning set forth in Section 2.1.1(a).

         "Letter of Credit  Agreement"  means an application and agreement for a
Standby  Letter  of  Credit,  in  such  form as may at any  time be  customarily
required by the Issuing Lender for its issuance of Standby Letters of Credit.

         "Letter  of Credit  Fees"  means the fee  payable  by the  Borrower  in
accordance with Section 2.2.2(b).

         "Net Worth"  means the excess of the total  assets of the  Borrower and
its Subsidiaries over total  liabilities,  as determined on a consolidated basis
in accordance with GAAP.

         "Operating  Income" means operating  income as determined in accordance
with GAAP, plus, to the extent included in the calculation of operating  income,
any amount taken as a one-time charge against  earnings  attributable to (i) the
settlement of the class action litigation  described in that certain  Disclosure
Letter  dated as of  February  16,  1999,  (ii) the  closing  of the  Borrower's
commercial  marine  division,  or (iii) charges  resulting from the reduction in
Borrower's   employees   resulting  from  the  Borrower's   switch  to  contract
manufacturing,  provided  that the amount of all such charges added to operating
income shall not exceed $2,000,000 in the aggregate.

         "Standby  Letter  of  Credit"  means  any  standby  letter of credit or
similar  instrument  issued or deemed  issued for the  account  of the  Borrower
pursuant  to Section  2.1.1 for the  purpose of  supporting  obligations  of the
Borrower  or  incurred  in the  ordinary  course of  business  with  respect  to
insurance obligations and workers' compensation,  surety bonds and other similar
statutory  obligations,  and all  obligations  customarily  supported by standby
letters of credit and satisfactory to the Issuing Lender.

         "Total Capitalization" means, as of the date of any determination,  the
sum of (i) Total Funded Debt, and (ii) Net Worth.

         "Total Funded Debt" means, as of the date of any determination, the sum
of (i) the principal amount of all Obligations,  including,  without limitation,
the Revolving Loans and the Letters of Credit,  (ii) the principal amount of all
Subordinated  Debt, and (iii) all Capitalized  Lease Obligations of the Borrower
and its Subsidiaries.

         "Unpaid Drawing" has the meaning set forth in Section 2.1.1(g).

     3. The first paragraph of Section 2.1 of the Agreement is hereby amended in
its entirety to read as follows:

         Section 2.1. The Revolving Credit Loans.  Each of the Lenders severally
agrees,  subject to the terms and  conditions of this  Agreement and provided no
Default or Event of Default has occurred and is continuing,  to make Advances of
Revolving  Credit Loans to the Borrower  from time to time after  receipt by the
Agent from time to time prior to the Revolving  Credit Repayment Date of, and at
the times  provided  for in, a Request and an Interest  Rate  Election  from the
Borrower in accordance with this Agreement,  during the period commencing on the
Closing Date and ending on the Business Day immediately  preceding the Revolving
Credit  Repayment  Date,  in an  aggregate  principal  amount  at any  one  time
outstanding  not to exceed the lesser of (i) such Lender's Pro Rata Share of the
Revolving  Credit Loan Commitment less (ii) in each case, such Lender's Pro Rata
Share of the  aggregate  outstanding  stated  amount of any Letters of Credit or
Letter of Credit Agreements and any Unpaid Drawing; and

         4.  Section  2.1 of the  Agreement  is hereby  further  amended  by the
addition of the  following  new Section  2.1.1  immediately  following  the last
paragraph thereof:

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         Section 2.1.1.    The Letters of Credit

               (a) Subject to the terms and  conditions  hereof and  provided no
Default or Event of Default has occurred and is continuing, at any time and from
time to time prior to the  Revolving  Credit  Repayment  Date,  the Borrower may
request  that the Issuing  Lender  issue for the account of the  Borrower one or
more irrevocable  Letters of Credit  denominated in Dollars,  and otherwise in a
form customarily  used by the Issuing Lender,  or in such other form as has been
approved by the Issuing Lender,  in support of such  obligations of the Borrower
described  in the  definitions  of  Standby  Letter  of  Credit  and  any  other
obligations of the Borrower that are reasonably  acceptable to the Agent and the
Issuing Lender and otherwise permitted to exist pursuant to this Agreement (each
such letter of credit, a "Letter of Credit").

               (b) The Issuing  Lender agrees to issue (subject to the terms and
conditions  contained herein) following its receipt of a request for a Letter of
Credit for the account of the Borrower  one or more  Letters of Credit  provided
that the  Issuing  Lender  shall be under no  obligation  to issue any Letter of
Credit if at the time of such issuance:

                        (i) any order,  judgment or decree of any  governmental
authority or arbitrator  shall purport by its terms to enjoin or restrain the 
Issuing  Lender from issuing such Letter of Credit or any requirement  of law  
applicable  to the Issuing Bank or any request or directive (whether or not 
having the force of law) from any  governmental  authority  with jurisdiction  
over the Issuing Lender shall prohibit or request that the Issuing Lender 
refrain from, the issuance of letters of credit  generally or such Letter of 
Credit in particular, or shall impose upon the Issuing Lender with respect to
such Letter of Credit any  restriction  or reserve or capital  requirement  (for
which the Issuing Lender is not otherwise compensated) not in effect on the date
of this  Agreement,  or any  unreimbursed  loss,  cost or expense  which was not
applicable,  in  effect  or known to the  Issuing  Lender as of the date of this
Agreement and which the Issuing Lender in good faith deems material to it; or

                        (ii) the Issuing Lender shall have received  notice from
any other Lender prior to the issuance of such Letter of Credit to the effect
that one or more of the conditions  specified in Section 3.1.2 are not then  
satisfied,  or that the  issuance  of such  Letter of Credit would violate any 
provision of this Section 2.1.1.

               (c) Notwithstanding the foregoing,  (i) no Letter of Credit shall
be issued if the stated amount of which,  when added to the aggregate  amount of
all  Letters  of Credit and any Unpaid  Drawing at such time,  would  exceed the
lesser of (x) $5,000,000,  and (y) when added to the aggregate  principal amount
of  all  Revolving  Credit  Loans  then  outstanding,  an  amount  equal  to the
Commitment;  and (ii) each Letter of Credit  shall by its terms  terminate or be
terminable by the Issuing  Lender on such date that would result in all drawings
thereunder,  being funded  pursuant to the terms thereof prior to the earlier of
(x) the date which occurs twelve (12) months after the date of issuance  thereof
(although any such Letter of Credit may be extendable for successive  periods of
up to twelve (12)  months,  but not beyond the sixth  Business  Day prior to the
Revolving Credit Repayment Date, on terms acceptable to the Issuing Lender), and
(y) the date  which is six (6)  Business  Days  prior  to the  Revolving  Credit
Repayment Date.

               (d)  Each  request  for a  Letter  of  Credit  shall  be  made by
submission  by the Borrower to the Agent of a Letter of Credit  Agreement,  duly
completed and executed by the Borrower and in effect at such time, no later than
five (5) Business  Days prior to the proposed  date of issuance of the Letter of
Credit,  provided  that  if the  express  provisions  of any  Letter  of  Credit
Agreement conflict with the express provisions of this Agreement, the provisions
of this agreement  shall control to the extent of such  conflict.  The making of
each request for a Letter of Credit shall be deemed to be a  representation  and


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warranty by the Borrower  that such Letter of Credit may be issued in accordance
with, and will not violate the  requirements  of, this Section 2.1.1.  The Agent
shall  promptly  notify,  and deliver to, the Issuing Lender each such Letter of
Credit Agreement.  Upon the issuance of any Letter of Credit, the Issuing Lender
shall promptly notify the Agent and each Lender of such issuance; and

               (e) Immediately upon issuance of a Letter of Credit,  the Issuing
Lender shall be deemed to have sold and  transferred to each Lender,  other than
the Issuing  Lender (each such Lender,  in its  capacity  under this  subsection
2.1.1(e),  an "LC  Participant") and each LC Participant shall be deemed to have
irrevocably and unconditionally  purchased and received from the Issuing Lender,
without recourse or warranty,  an undivided  interest and  participation in such
Letter of Credit to the extent of such LC  Participant's  Pro Rata Share in such
Letter of Credit,  each  drawing  made  thereunder  and the  obligations  of the
Borrower with respect thereto,  and any security therefor or guaranty pertaining
thereto.  Upon any change in the  Commitment,  or in the Pro Rata  Shares of the
Lenders pursuant to Section 9.11 hereof,  it is hereby agreed that, with respect
to all outstanding  Letters of Credit and any Unpaid Drawing at such time, there
shall  be an  automatic  adjustment  to  the  participations  pursuant  to  this
subsection  2.1.1(e) to reflect the new Pro Rata Shares of any assigning  Lender
and its assignee or of all Lenders with respect to the  Commitment,  as the case
may be;

               (f) In determining whether to pay under any Letter of Credit, the
Issuing Lender shall have no obligation relative to the other Lenders other than
to confirm  that any  documents  required to be  delivered  under such Letter of
Credit  appear to have been  delivered  and that  they  appear to  substantially
comply on their face with the requirements of such Letter of Credit.  Any action
taken or omitted to be taken by the Issuing  Lender under or in connection  with
any Letter of Credit if taken or omitted in the absence of gross  negligence  or
willful  misconduct,  shall not create  for the  Issuing  Lender  any  resulting
liability to the Borrower, the Guarantors, the Agent or any other Lender.

               (g) The Borrower agrees to reimburse the Issuing Lender by making
payment to the Issuing  Lender in immediately  available  funds at the office of
the Issuing  Lender  specified  for such  payment by the Issuing  Lender for any
payment or  disbursement  made by the Issuing  Lender under any Letter of Credit
(each, an "Unpaid Drawing")  immediately after, and, in any event on the date of
such payment or  disbursement,  with interest on the amount so paid or disbursed
by the Issuing  Lender to the extent not reimbursed  prior to 2.00 P.M.  (Boston
time) on the date of such payment or  disbursement,  from and including the date
paid or disbursed to but excluding the date the Issuing Lender was reimbursed by
the Borrower  therefor at a rate equal to the Default Rate.  The Issuing  Lender
shall  give the  Borrower  prompt  notice of each  drawing  under any  Letter of
Credit,  provided  that the  failure  to give any  such  notice  shall in no way
affect, impair or diminish the Borrower's  obligations  hereunder.  The Borrower
hereby  authorizes  and  instructs  the  Issuing  Lender to charge  against  the
Borrower's  accounts with the Issuing  Lender on each date on which a payment is
due under a Letter of Credit,  and on any  subsequent  date if and to the extent
any such payment is not made when due, an amount up to the  principal,  interest
and fees due and payable to the Issuing Lender  thereunder and such charge shall
be deemed payment thereunder to the extent that immediately  available funds are
then in such  accounts.  The  Issuing  Lender  shall use  reasonable  efforts in
accordance  with the Issuing  Lender's  customary  procedures to give subsequent
notice of any such charge to the  Borrower,  but the failure to give such notice
shall not affect the validity of any such charge;

               (h) In the event that the Issuing  Lender makes any payment under
any Letter of Credit and the Borrower shall have failed to reimburse the Issuing
Lender  under any  Letter of  Credit  or  Letter  of Credit  Agreement,  and any
outstanding  Indebtedness of the Borrower relating  thereto,  the Issuing Lender
shall promptly notify the Agent, which shall promptly notify each LC Participant
of such  failure,  and each LC  Participant  shall  promptly  pay to the Issuing
Lender in  Dollars  its Pro Rata Share of such  unreimbursed  amount in same day

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funds. If the Agent so notifies,  prior to 12 P.M. (Boston time) on any Business
Day, each such LC  Participant  shall make  available to the Issuing Lender such
payment on such Business  Day, or if such notice is given after 12 P.M.  (Boston
time) on any Business  Day, on the next  succeeding  Business Day. If and to the
extent that any such LC Participant  shall not have so made such funds available
to the Issuing Lender,  such LC Participant  agrees to pay to the Issuing Lender
forthwith on demand such amount  together  with interest  thereon,  for each day
from the date such amount was due under this subsection  2.1.1(h) until the date
such  amount is paid to the Issuing  Lender,  at the  Federal  Funds  Rate.  The
obligations  of each LC  Participant  under this  subsection  2.1.1(h)  shall be
absolute  and  unconditional  and all  payments  due  from  each LC  Participant
hereunder  shall be made  notwithstanding  the occurrence or  continuation of an
Event of Default or the failure to satisfy any  condition set forth in Article 3
of this Agreement;

               (i)  Whenever  the  Issuing  Lender   receives  a  payment  of  a
reimbursement  obligation  as to which it has received any payments  from the LC
Participants pursuant to subsection 2.1.1(h) above, the Issuing Lender shall pay
to each LC Participant which has paid its Pro Rata Share thereof, in Dollars and
in same day funds,  an amount equal to such LC  Participant's  share (based upon
the  proportionate  aggregate amount originally funded by such LC Participant to
the aggregate  amount funded by all LC  Participants) of the principal amount of
such  reimbursement  obligation and interest thereon accruing after the purchase
of the respective participations;

               (j) The obligation of each LC Participant to make payments to the
Issuing  Lender with  respect to any Letter of Credit and such LC  Participant's
participation therein and the obligation of the Borrower to make payments to the
Issuing  Lender,  shall  not  be  subject  to  any  qualification  or  exception
whatsoever and shall be made in accordance with the terms and conditions of this
Agreement, including, without limitation, any of the following circumstances:

                        (i)  Any lack of validity or enforceability of this 
Agreement or any of the other Financing Documents;

                        (ii) The  existence  of any claim,  set-off,  defense or
other right which the Borrower may have at any time against a beneficiary named 
in a Letter of Credit or any transferee or assignee of any Letter of Credit 
(or any Person for whom any such  transferee or assignee may be acting),  the 
Issuing Lender, the Agent, any Lender, or any other Person, whether  in  
connection  with  this  Agreement,   any  Letter  of  Credit,  the transactions
contemplated herein or any unrelated  transactions  (including any underlying  
transactions  between  the  Borrower  or any  other  Person  and the
beneficiary named in any Letter of Credit);

                        (iii)  Any  draft,  certificate  or any  other  document
presented under the Letter of Credit upon which payment has been made in good  
faith and  according  to its terms  proving to be forged, fraudulent,  invalid 
or  insufficient  in any respect or any  statement  therein being untrue or 
inaccurate in any respect;

                        (iv)  The  surrender  or  impairment  of any collateral
or any  other  security  for the  Obligations  or the performance or observance 
of any of the terms of any of the Financing Documents;

                    (v)  The occurrence of any Default or Event of Default; or

                    (vi)  The failure to give notice of the issuance of any 
Letter of Credit;

provided that, no LC Participant shall be obligated to pay such LC Participant's
Pro Rata Share of any unreimbursed amount arising from any wrongful payment made
by the issuing  Lender under a Letter of Credit as a result of acts or omissions
constituting  willful  misconduct or gross negligence on the part of the Issuing
Lender.

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               (k) Indemnification.  In addition to amounts payable as elsewhere
provided in this Agreement,  the Borrower agrees to protect,  indemnify, pay and
save  the  Issuing  Lender,   the  Agent,  the  Syndication  Agent  and  the  LC
Participants harmless from and against any and all claims, demands, liabilities,
damages,  losses,  costs, charges and expenses (including  reasonable attorneys'
fees)  which the  Issuing  Lender,  the Agent or any LC  Participant  (each,  an
"Indemnified  Party") may incur or be subject to (other than as a result of acts
or omissions of any such  Indemnified  Party  constituting  gross  negligence or
willful  misconduct  as determined  by a court of competent  jurisdiction)  as a
consequence, directly or indirectly, of

                    (i)  the issuance of any Letter of Credit; or

                        (ii)  the  failure  of the  Issuing  Lender  to  honor a
drawing under any Letter of Credit as a result of any act or omission,  whether 
rightful or wrongful, of any present or future de jure or de facto governmental
authority (all such acts or omissions being  hereinafter referred to 
collectively as "Government Acts").

               (l) As  among  the  Borrower  and the  Indemnified  Parties,  the
Borrower assumes all risks of the acts and omissions of, or misuse of any of the
Letters of Credit by, the respective beneficiaries of such Letters of Credit. In
furtherance and not in limitation of the foregoing, subject to the provisions of
the  Letter  of  Credit  Agreements,   the  Indemnified  Parties  shall  not  be
responsible for:

                        (i) the form,  validity,  sufficiency,  accuracy,  
genuineness or legal effect of any document submitted by any Person in 
connection with the  application for and issuance of and presentation of drafts 
with respect to any of the Letters of Credit, even if it should prove to be, in 
any or all respects, invalid, insufficient,  inaccurate, fraudulent or forged;

                        (ii) the validity or  sufficiency  of any  instrument  
transferring  or assigning or  purporting to transfer or assign any Letter of 
Credit or the rights or  benefits  thereunder  or  proceeds thereof,  in whole 
or in part,  which may prove to be invalid or ineffective for any reason;

                    (iii)  the failure of any drawing to strictly comply with 
the terms of a Letter of Credit;

                        (iv)  errors,  omissions,  interruptions  or  delays  in
transmission or delivery of any messages, by mail, cable, telegraph, telex or 
otherwise, whether or not they be indecipherable;

                        (v) errors in  interpretation  of technical  terms other
than those resulting from gross negligence or willful misconduct;

                        (vi) any loss or delay in the  transmission or otherwise
of any document required in order to make a drawing under any Letter of Credit 
or of the proceeds thereof;

                        (vii) the  non-application  or misapplication by the 
beneficiary of any Letter of Credit of the proceeds of any drawing under such 
Letter of Credit; or

                        (viii) any  consequences  arising from causes beyond the
control of the Issuing Lender, the Agent or any LC Participant, including, 
without limitation, any Government Acts.

None of the foregoing shall affect,  impair or prevent the vesting of any of the
Indemnified Parties' rights or powers under this Section 2.1.1.

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               (m)  If,  notwithstanding  the  provisions  of  Section  2.1.1(c)
hereof,  any Letter of Credit is outstanding on the Revolving  Credit  Repayment
Date (each,  a  "Post-Termination  Letter of  Credit"),  then on or prior to the
Revolving  Credit  Payment Date, the Borrower  shall,  promptly on demand by the
Issuing  Lender,   deposit  with  the  Issuing  Lender,  with  respect  to  each
Post-Termination Letter of Credit then outstanding,  as the Issuing Lender shall
specify, cash collateral ("Cash Collateral") in an amount necessary to reimburse
the  Issuing  Lender for  payments to be made by the  Issuing  Lender  under any
Post-Termination  Letter of Credit.  Such Cash  Collateral  shall be held by the
Issuing  Lender,  as  security  for,  and to  provide  for the  payment  of, the
obligations  of the  Borrower  with respect to the  Post-Termination  Letters of
Credit.  In the event  that any  amount  of Cash  Collateral  remains  after the
expiration of all  Post-Termination  Letters of Credit, so long as no Obligation
which is then due and payable is  outstanding  on such date,  the Issuing Lender
shall return such amount promptly to the Borrower.

         5. Section 2.2.2 of the Agreement is hereby  amended by the addition of
the following new Section 2.2.2.4 immediately at the end thereof:

         2.2.2.4  Letter of Credit Fees. The Borrower shall pay to the Agent for
the account of the  Issuing  Lender and each LC  Participant  for each Letter of
Credit  issued by the  Lender a per annum  fee equal to the  product  of (x) the
stated amount  thereof,  and (y) the Applicable  Margin then in effect for Libor
Loans, payable annually in advance on the date of issuance and each renewal date
thereof,  plus,  an  additional  amount  payable on the dates  specified  by the
Issuing  Lender and for the sole account of the Issuing  Lender,  such  standard
fees and  costs  as the  Issuing  Lender  may from  time to time  establish  for
issuance, transfer, amendment and negotiation of each Letter of Credit and other
customary  charges of the Issuing  Lender with  respect  thereto (the "Letter of
Credit Fees").

         6. Section 2.6.4 of the Agreement is hereby  amended in its entirety to
read as follows:

                  Section  2.6.4.  Permanent  Reduction  of  Commitment.  At the
Borrower's option, the Commitment may be permanently and irrevocably  reduced in
whole or in part by an amount of at least  $500,000  and to the extent in excess
thereof in integral  multiples  of $100,000 at any time;  provided  that (i) the
Borrower  gives the Agent written notice of the exercise of such option at least
three (3) Business Days prior to the effective date thereof,  (ii) the aggregate
outstanding balance of the Revolving Credit Loans plus the aggregate outstanding
amount of any  Letters of Credit and any  Undrawn  Amounts,  does not exceed the
Commitment, as so reduced on the effective date of such reduction, and (iii) the
Borrower is not,  and after  giving  effect to such  reduction,  would not be in
violation of Section 2.6.3.  Any such reduction  shall  concurrently  reduce the
Dollar amount of each Lender's Pro Rata Share of the Commitment.

         7.  Section  2.6 of the  Agreement  is hereby  further  amended  by the
addition of the following new Section 2.6.5 immediately at the end thereof:

                  Section 2.6.5. If at any time the aggregate  principal  amount
of the Revolving  Credit Loans plus the aggregate  outstanding  stated amount of
any Letters of Credit and any Unpaid  Drawing shall exceed the  Commitment,  the
Borrower shall immediately pay to the Agent in immediately available Dollars for
the ratable account of the Lenders the amount of such excess.

         8. Section 2.8 of the  Agreement  is hereby  amended in its entirety to
read as follows:

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     Section 2.8. Use of  Proceeds.  The Borrower  shall use the proceeds of the
Loans and obtain Letters of Credit solely for Borrower's working capital and for
general corporate purposes.

         9. Section 3.1.2 of the Agreement is hereby  amended in its entirety to
read as follows:

                  Section  3.1.2.   Conditions   Precedent  To  All  Loans.  The
Commitment  and the  obligation  of each Lender to make or maintain its Pro Rata
Share of any Advance or Loan and/or the Issuing  Lender to consider  any request
for a Letter of Credit,  are subject to  performance  by the Borrower of all its
obligations  under  this  Agreement  and to the  satisfaction  of the  following
further conditions precedent:

                  (a) The fact that, immediately prior to and upon the making of
each Loan or  issuance  of any Letter of Credit,  no Event of Default or Default
shall have occurred and be continuing;

                  (b) The fact that the  representations  and  warranties of the
Borrower  contained  in  Article  4,  infra and in each of the  other  Financing
Documents,  are true and correct in all material  respects on and as of the date
of each Advance, Loan or Letter of Credit except as altered hereafter by actions
consented to or not prohibited  hereunder.  The Borrower's delivery of the Notes
to the Lenders and of each  Request and Letter of Credit  Agreement to the Agent
shall be deemed to be a  representation  and  warranty by the Borrower as of the
date of such  Advance,  Loan or Letter of  Credit as to the facts  specified  in
Sections 3.1.2(a) and (b);

                  (c)  Receipt  by the  Agent on or prior  to the  Business  Day
specified  in the  definition  of Interest  Rate  Election of a written  Request
stating the amount requested for the Loan or Advance in question and an Interest
Rate  Election  for  such  Loan or  Advance,  all  signed  by a duly  Authorized
Representative of the Borrower on behalf of the Borrower;

                  (d) That there exists no law or regulation by any governmental
authority having  jurisdiction  over the Agent or any of the Lenders which would
make it  unlawful  in any  respect for such Lender to make its Pro Rata Share of
the Loan or  Advance,  or  purchase  a  participation  in any  Letter of Credit,
including, without limitation, Regulations U, T, and X of the Board of Governors
of the Federal Reserve System; and

                  (e)      No Material Adverse Effect has occurred.

         10. Section  5.1.10 of the Agreement  ("Minimum  Fixed Charge  Coverage
Ratio") is hereby  deleted in its entirety and the following new Section  5.1.10
inserted in its stead:

                  Section  5.1.10.  Maximum  Ratio of Total Funded Debt to Total
Capitalization. Commencing January 1, 1999, maintain a ratio of (i) Total Funded
Debt to (ii) Total Capitalization of less than .55:1.00.

         11.  Section  5.1.11 of the Agreement is hereby amended in its entirety
to read as follows:

                  Section 5.1.11.  Minimum Consolidated  Tangible Net Worth. (i)
Maintain  a  Consolidated  Tangible  Net  Worth in an  amount  not less than the
Borrower's  Consolidated Tangible Net Worth as of the end of the Borrower's 1998
fiscal  year,  minus  $5,000,000,  and (ii) comply  with  Section 8K of the Note
Purchase  Agreement  dated as of June 13, 1994 among the Borrower,  John Hancock
Mutual Life and John Hancock Life Insurance, as the same may be amended, amended
and restated, supplemented or otherwise modified from time to time.

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         12.  Section 5.1.12 of the Agreement is hereby is hereby deleted in its
entirety and the following new Section 5.1.12 inserted in its stead:

                  Section 5.1.12.  Minimum Cash Balances.  Maintain at all times
on and after February 16, 1999  unrestricted cash balances in an amount equal to
or  greater  than  (x) on any  date  prior  to the  delivery  of the  Borrower's
financial  statements  to the Agent  pursuant  to Section  5.3.3 and the related
Officer's  Certificate as required by Section 5.3.4 reflecting  Operating Income
and  Net  Income  equal  to or  greater  than  one  dollar  ($1.00)  for two (2)
consecutive  fiscal  quarters,  the sum of (i)  $25,000,000,  plus fifty percent
(50%) or more of the aggregate principal  outstanding amount of all Obligations,
including,  without limitation, the Revolving Loans and the Letters of Credit in
one or more accounts  maintained  by the Borrower with the Agent,  plus (ii) the
balance of such  Obligations in one or more accounts  maintained by the Borrower
with a Lender other than the Agent,  and (y)  thereafter (i) fifty percent (50%)
or  more of the  aggregate  outstanding  principal  amount  of all  Obligations,
including,  without  limitation,  the Revolving Loans and the Letters of Credit,
plus (ii) the balance of the principal amount of such Obligations in one or more
accounts maintained by the Borrower with a Lender other than the Agent.

         13.  Section  5.1.13 of the Agreement is hereby amended in its entirety
to read as follows:

                  Section  5.1.13.  Minimum  Quick Ratio  Maintain at the end of
each fiscal  quarter of the  Borrower a ratio of (i) the sum of (w) cash on hand
or on deposit in any bank or trust company which has not suspended business, (x)
Cash Equivalent Investments (without duplication with clause (w) above), and (y)
net outstanding amount of accounts  receivable to (ii) (x) Current  Liabilities,
excluding  the  principal  outstanding  amount  of any  Obligations  at any time
classified as Current Liabilities, of not less than 1.5:1.0. Each item described
in clauses (i) and (ii) of this  Section  5.1.13 shall be  calculated  as of the
last day of the Borrower fiscal quarter and include only the item(s) in question
of the Borrower and its Subsidiaries on a consolidated basis.

         14. Section 5.2.3 of the Agreement is hereby amended in its entirety to
read as follows:

                  Section 5.2.3. Acquisitions, Dissolution, etc. Acquire, in one
or  a  series  of  transactions,  any  properties  or  assets  (other  than  the
acquisition  of inventory,  materials  and  equipment in the ordinary  course of
business) or ownership interests in another Person, or dissolve, liquidate, wind
up, merge or  consolidate  or combine with another  Person  (other than mergers,
consolidations  or other  combinations  in which the  Borrower is the  surviving
entity);  (i) on any date  prior to the  delivery  of the  Borrower's  financial
statements to the Agent pursuant to Section 5.3.3 reflecting  operating  income,
as determined in accordance  with GAAP,  and Net Income equal to or greater than
one dollar ($1.00),  and (ii) as to which on or before the thirtieth  (30th) day
prior to the consummation of any such acquisition, the Borrower has delivered to
the Agent a pro-forma Compliance  Certificate on a consolidated basis (including
the to-be-acquired  assets and any assumed liabilities or if ownership interests
are acquired, the to-be-acquired Person if such Person is to be a Subsidiary and
if not, the to-be-acquired  ownership interests, all measured as set forth below
in this  Section  5.2.3),  which such  pro-forma  Compliance  Certificate  shall
indicate  that no Default or Event of Default  exists or would  exist  following
consummation  of the  permitted  transaction  and that the Borrower  would be in
compliance with (on a consolidated basis including the to-be-acquired assets and
any  assumed   liabilities   or  if  ownership   interests  are  acquired,   the
to-be-acquired  Person if such  Person  is to be a  Subsidiary  and if not,  the
to-be-acquired  ownership interests),  Sections 5.1.10, 5.1.10A,  5.1.11, 5.1.12
and 5.1.13 and Sections 5.2.8 and 5.2.9 following  consummation of the permitted
transaction,  including the to-be-acquired assets, Person or ownership interests
and the operating  results thereof on the same basis and for the same periods as
the Borrower is measured for each such covenant, respectively.

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         15. Section 5.2.4 of the Agreement is hereby amended in its entirety to
read as follows:

                  Section 5.2.4.  Disposition of Assets.  Effect any disposition
of material  assets,  other than (i) the  disposition  of assets in the ordinary
course of  business,  consistent  with past  practices,  (ii) subject to Section
5.2.8, the disposition of assets not to exceed 15% of Consolidated  Tangible Net
Worth in the aggregate over the period commencing on the Closing Date and ending
on August 31, 2000,  the value of which assets shall be based upon the aggregate
book value of all such assets  determined as of the date of the sale thereof and
prior to such  disposition,  and (iii) in  addition  to  dispositions  of assets
permitted  under clauses (i) and (ii) of this Section 5.2.4,  the disposition of
assets associated with the Borrower's transition to contract manufacturing.

         16. Section 5.2.9 of the Agreement is hereby amended in its entirety to
read as follows:

                  Section 5.2.9.  Minimum  Operating and Net Income.  (i) During
the period beginning with the Borrower's  fiscal quarter ending March,  1999 and
ending on the fiscal quarter ending  December,  1999, have a negative  Operating
Income or a negative Net Income for any two fiscal quarters,  and (ii) as of the
end of each fiscal quarter of the Borrower commencing with the Borrower's fiscal
quarter ending in March,  2000, have a negative  Operating Income, or a negative
Net Income for the rolling four quarter fiscal period  consisting of such fiscal
quarter and the three immediately preceding fiscal quarters.

         17.  Section  5.2.10  of  the  Agreement   ("Dividends,   Payments  and
Distributions")   is  hereby  amended  by  deleting  clause  (iii)  thereof  and
substituting in its stead the following new clause (iii):

                  (iii) on any date  following  the  delivery of the  Borrower's
financial  statements  to the Agent  pursuant  to Section  5.3.3 and the related
Officer's  Certificate as required by Section 5.3.4 reflecting  Operating Income
and Net  Income  equal to or  greater  than one  dollar  ($1.00)  for  three (3)
consecutive  fiscal  quarters,  the Borrower  shall be  permitted to  repurchase
shares of its own capital stock provided that on or before the thirtieth  (30th)
day prior to the consummation of any such repurchase, the Borrower has delivered
to the Agent a pro-forma  Compliance  Certificate on a consolidated basis, which
such  pro-forma  Compliance   Certificate  shall  indicate  that,  assuming  the
repurchase  had  occurred  on the  last day of the most  recently  ended  fiscal
quarter,  no  Default  or Event of  Default  exists  or  would  exist  following
consummation  of such  repurchase  and that,  after giving effect  thereto,  the
Borrower would be in compliance with Sections 5.1.10,  5.1.10A,  5.1.11,  5.1.12
and 5.1.13 and Sections 5.2.8 and 5.2.9.

        18. Exhibit  3.1.1.10 to the Agreement (Form of Compliance  Certificate)
is hereby  deleted and a new Exhibit  3.1.1.10 in the form attached  hereto as "
Exhibit 3.1.1.10 " substituted in its stead.

                  This Amendment shall take effect as of the Effective Date upon
receipt  by the  Agent of the last item  specified  below  (other  than any item
expressly deferred or waived in writing by the Majority Lenders):

                  (i)      this Amendment duly executed by the parties hereto;

                  (ii) a certificate of the Secretary or an Assistant  Secretary
of  the  Borrower  with  respect  to  resolutions  of  its  Board  of  Directors
authorizing  the  execution  and  delivery  of this  Amendment,  and  any  other


                                       99


documents required to be delivered by this Amendment, identifying the officer(s)
authorized to execute, deliver and take all other actions required thereunder;

                  (iii)  a  Disclosure  Letter  executed  by the  Borrower  with
respect to the representations and warranties contained in the Loan Agreement;

                  (iv) an Escrow  Agreement  and each of the Security  Documents
required by the Agent in connection  with the creation and  perfection of a Lien
on all assets of the Borrower in favor of the Collateral  Agent, for the benefit
of the Agent,  the Syndication  Agent,  the Issuing  Lender,  and the Lenders as
security  for the  Obligations  duly  executed by an  authorized  officer of the
Borrower,  (v) an  Opinion  of the  Borrower's  counsel  with  respect  to  this
Amendment  and the Security  Documents  and the Escrow  Agreement  referenced in
clause (iv) above;

                  (v)      payment to the Agent, for the ratable benefit of 
the Lenders approving this Amendment,  of the amendment fee in the amount of 
$50,000; and

                  (vi) such other documents,  and evidence of completion of such
other  matters,  as the  Agent  or the  Required  Lenders  reasonably  may  deem
necessary or desirable.

         The  Borrower  hereby  represents  and  warrants to the Lenders that no
Default or Event of Default exists under the  Agreement.  Nothing in this Second
Letter of Amendment shall be construed to be an amendment of any other provision
of the Agreement and all of the provisions of the Agreement shall remain in full
force and effect.

         This Amendment supersedes the December 9, 1998 Supplement, the terms of
which shall have no further force or effect.

         This  Amendment  is executed as an  instrument  under seal and shall be
governed by and construed in  accordance  with the laws of The  Commonwealth  of
Massachusetts  without  regard to its  conflicts of law rules.  All parts of the
Agreement not affected by this Amendment are hereby ratified and affirmed in all
respects,  provided that if any provision of the Agreement  shall conflict or be
inconsistent  with this  Amendment,  the terms of this Amendment shall supersede
and prevail.  Upon and after the date of this  Amendment  all  references to the
Agreement in that document, or in any related document, shall mean the Agreement
as amended by this  Amendment.  Except as expressly  provided in this Amendment,
the execution and delivery of this Amendment does not and will not amend, modify
or  supplement  any  provision of, or constitute a consent to or a waiver of any
noncompliance with the provisions of the Agreement,  and, except as specifically
provided in this Amendment, the Agreement shall remain in full force and effect.
This Amendment may be executed in one or more  counterparts with the same effect
as if the signatures hereto and thereto were upon the same instrument.







                      [THIS SPACE INTENTIONALLY LEFT BLANK]


                                       100



         IN WITNESS  WHEREOF,  each of the Borrower,  the Agent, the Syndication
Agent,  and the Lenders in  accordance  with Section 9.5 of the  Agreement,  has
caused this  Amendment to be executed and  delivered  by their  respective  duly
authorized officers as an instrument under seal as of the Effective Date.

                        BORROWER:

                           TRIMBLE NAVIGATION LIMITED


                          By: /s/ John E. Huey
                                  John E. Huey
                                  Treasurer


                        AGENT:

                           FLEET NATIONAL BANK


                          By:/s/ Mathew M. Glauninger
                                 Mathew M. Glauninger
                                 Vice President and Senior
                                 Relationship Manager


                        SYNDICATION AGENT:

                          BANKBOSTON, N.A.


                          By: /s/ Anthony B. Kwee
      Print Name                  Anthony   B. Kwee
                          Title: Vice President



                                      101

                  LENDERS:

                     FLEET NATIONAL BANK


                      By: /s/ Mathew M. Glauninger              
                              Mathew M. Glauninger
                              Vice President and Senior
                              Relationship Manager


                     BANKBOSTON, N.A.

                     By: /s/ Anthony B. Kwee                         
          Print Name         Anthony B. Kwee
                      Title: Vice President


                     SANWA BANK CALIFORNIA

                     By:
          
          Print Name
                      Title:


                     ABN AMRO BANK N.V.

                     By: /s/ Dianne D. Barkley         
         Print Name          Diannie D. Barkley
                      Title: Group Vice President
                                                       

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