Roland SERVICE INFORMATION NO 100208


                                  JP-6


                                 SUBJECT
    
             Installing MIDI "THRU" Socket & Associated Design Changes
    
        For more convenient use in MIDI operation, MIDI THRU socket is
        installed on the JP-6 with SN 353800 and subsequent (October
        production). Electrical details are illustrated in the circuit
        diagram and PCB layouts enclosed.
        The major aspects of changes and related information are as
        follows.

        1. JACK BOARD
           COMPATIBILITY
           Electrically YES, provided that Jack Board Mounting CHASSIS
           and TOP Panel are also changed to accomodate the dimensional
           differences.

        2. PHOTO COUPLER (OPTO-ISOLATOR) Either PC-900 or TLP552 (15229706)
           is mounted an the new PCB. The latter, however, will successively
           be used because of its high-speed capability.
    
         CAUTION  :
             When replacing the exist photo coupler with other type, follow
         PCB layouts enclosed. There are misprints on the actual new PCB.
    
        3. PROM (IC26, CPU BOARD)
           The software in this 2732A-A is changed to Version 3 which
           includes the following improvements :

             1) Completely complies with MIDI Spec. Ver-1.0.
             2) Can transmit On/Off information of each key during
                program change.
             3) Ensures the reading of ARPEGGIO key events (clocks).

        NOTE :  The Ver.3 can be a substitutive for Ver's 1 and 2 but
                reverse does not hold true.