SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549
                            -------------------------

                                  SCHEDULE 13G
                                 (Rule 13d-102)

                    INFORMATION TO BE INCLUDED IN STATEMENTS
                  FILED PURSUANT TO RULES 13d-1(b), (c) AND (d)
                AND AMENDMENTS THERETO FILED PURSUANT TO 13d-2(b)
                        (Amendment No. ______5______)(1)

                              Electro-Sensors, Inc.

                                (Name of Issuer)

                          Common Stock, $0.10 par value
                         (Title of Class of Securities)

                            ________285233102 ______

                                 (CUSIP NUMBER)

                                 April 26, 2006


             (Date of Event Which Requires Filing of this Statement)


Check the appropriate box to designate the rule pursuant to which this Schedule
is filed:

                      /   /     Rule 13d-1(b)
                      /   /     Rule 13d-1(c)
                      /   /     Rule 13d-1(d)


-----------------------------

(1)  The  remainder  of this  cover  page  shall be filled  out for a  reporting
     person's  initial  filing on this form with respect to the subject class of
     securities,  and for any subsequent amendment containing  information which
     would alter disclosures provided in a prior cover page.

     The  information  required on the remainder of this cover page shall not be
     deemed to be  "filed"  for the  purpose  of  Section  18 of the  Securities
     Exchange  Act of 1934  or  otherwise  subject  to the  liabilities  of that
     section of the Act but shall be subject to all other  provisions of the Act
     (however, see the Notes).








                                                                                                    


---------------------------------------------------------------------------------------------------------------
NAME OF REPORTING PERSONS:
     I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)
---------------------------------------------------------------------------------------------------------------
CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

                                                                                                 (A)        X
                                                                                                 (B)
---------------------------------------------------------------------------------------------------------------
SEC USE ONLY
---------------------------------------------------------------------------------------------------------------
CITIZENSHIP OR PLACE OF ORGANIZATION UNITED STATES OF AMERICA

---------------------------------------------------------------------------------------------------------------
NUMBER OF SHARES    SOLE VOTING POWER                                                                     0
BENEFICIALLY
  OWNED BY
    EACH
  REPORTING
 PERSON WITH

---------------------------------------------------------------------------------------------------------------
                    SHARED VOTING POWER 0
---------------------------------------------------------------------------------------------------------------
                    SOLE DISPOSITIVE POWER 0
---------------------------------------------------------------------------------------------------------------
                    SHARED DISPOSITIVE POWER 0
---------------------------------------------------------------------------------------------------------------
     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON                                            0

---------------------------------------------------------------------------------------------------------------
 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*
---------------------------------------------------------------------------------------------------------------
     PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)                                                   0.00%
---------------------------------------------------------------------------------------------------------------
 TYPE OF REPORTING PERSON* IN
---------------------------------------------------------------------------------------------------------------

                   *SEE INSTRUCTION BEFORE FILLING OUT!



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Item 1(a).        Name of Issuer:

                           Electro-Sensors, Inc.

Item 1(b).        Address of Issuer's Principal Executive Offices:

                           6111 Blue Circle Drive
                           Minnetonka, Minnesota 55343-9108

Item 2(a).        Name of Person Filing:

                           Daniel Zeff
                           (the "Reporting Person")

Item 2(b).        Address of Principal Business Office or, if None, Residence:

                           The principal business address of the Reporting
Person is:

                           c/o Zeff Holding Company, LLC
                           50 California Street, Suite 1500
                           San Francisco, CA 94111


Item 2(c).        Citizenship:

                           Mr. Zeff is a United States citizen.

Item 2(d).        Title of Class of Securities:

                           Common Stock, $0.10 par value

Item 2(e).        CUSIP Number:

                           285233102




                                      -3-





Item 3.    If this statement is filed pursuant to Rule 13d-1(b), or 13d-2(b) or
           (c), check whether the person filing is a:  Not Applicable

          (a)  [ ] Broker or dealer  registered under Section 15 of the Exchange
               Act;

          (b)  [ ] Bank as defined in Section 3(a)(6) of the Exchange Act;

          (c)  [ ]  Insurance  Company as defined  in  Section  3(a)(19)  of the
               Exchange Act;

          (d)  [  ]  Investment  Company  registered  under  Section  8  of  the
               Investment Company Exchange Act;


          (e)  [  ]    Investment    Adviser    in    accordance    with   Rule
               13d-1(b)(1)(ii)(E);

          (f)  [ ] Employee  Benefit Plan or Endowment  Fund in accordance  with
               Rule 13d-1(b)(1)(ii)(F);

          (g)  [ ] Parent Holding  Company or Control Person in accordance  with
               Rule 13d-1(b)(1)(ii)(G);

          (h)  [ ] Saving  Association as defined in Section 3(b) of The Federal
               Deposit Insurance Act;

          (i)  [ ]  Church  Plan  that is  excluded  from the  definition  of an
               Investment  Company  under  Section  3(c)(14)  of the  Investment
               Company Act;

          (j)  [ ] Group,  in accordance with Rule  13d-1(b)(1)(ii)(J).




                                                                                                                 

Item 4.               Ownership.

                  A.  Daniel Zeff

(a) Amount beneficially owned:                                                                                      0
(b) Percent of Class:                                                                                           0.00%
(c) Number of shares as to which such person has:

                      (i)    Sole power to vote or direct the vote:                                                0
                      (ii)   Shared power to vote or to direct the vote:                                           0
                      (iii)  Sole power to dispose or direct the disposition of:                                   0
                      (iv)   Shared power to dispose or to direct the disposition of:
                                                                                                                   0





                                      -4-



                     As calculated in accordance with Rule 13d-3 of the
                     Securities Exchange Act of 1934, as amended, Daniel Zeff
                     beneficially owns 0 shares of the Issuer's Common Stock,
                     $0.10 par value ("Common Stock"), representing 0.00% of the
                     Common Stock. Mr. Zeff does not directly own any shares of
                     Common Stock, but he indirectly owns 0 shares of Common
                     Stock in his capacity as the sole manager and member of
                     Zeff Holding Company, LLC a Delaware limited liability
                     company ("ZHC") which in turn serves as the general partner
                     for Zeff Capital Partners I, L.P. ("ZCP"), a Delaware
                     Limited Partnership. Mr. Zeff also provides discretionary
                     investment management services to Zeff Capital Offshore
                     Fund ("ZCF"), a class of shares of Spectrum Galaxy Fund
                     Ltd., a company incorporated in the British Virgin Islands.

Item 5.           Ownership of Five Percent or Less of a Class.

                           If this statement is being filed to report the fact
                           that as of the date hereof the reporting person has
                           ceased to be the beneficial owner of more than five
                           percent of the class of securities, check the
                           following: [ ]

Item 6.           Ownership of More than Five Percent on Behalf of Another
                  Person.

                           Each of ZCP and ZCF have the right to receive and the
                           power to direct the receipt of dividends from, and
                           the proceeds from the sale of, the shares of Common
                           Stock held by them.

Item 7.           Identification and Classification of the Subsidiary Which
                  Acquired the Security Being Reported on by the Parent Holding
                  Company.

                           Not Applicable

Item 8.           Identification and Classification of Members of the Group.

                           Not Applicable

Item 9.           Notice of Dissolution of Group.

                           Not Applicable


                                      -5-



Item 10.          Certification.

         By signing below I certify that, to the best of my knowledge and
belief, the securities referred to above were not acquired and are not held for
the purpose of or with the effect of changing or influencing the control of the
issuer of the securities and were not acquired and are not held in connection
with or as a participant in any transaction having that purpose or effect.

                                    SIGNATURE


         After reasonable inquiry and to the best of my knowledge and belief, I
certify that the information set forth in this statement is true, complete and
correct.

Dated:  May 2, 2006
                                                             /s/ Daniel Zeff
                                                             ---------------





     Attention:  Intentional  misstatements  or  omissions  of  fact  constitute
Federal criminal violations (see 18 U.S.C. 1001).






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