HOSL98

Proper installation of the Hammond Organ - Dec 9, 1955

 The Hammond Organ is a highly flexible musical instrument.


 1.  setting the tone control. (all consoles except 'M' series)

 2a. Adjustment of the Percussion cut-off control. B3, C3, RT3

 2b. Adjustment of the Percussion cut-off control. M3

 3a.  ?Replacement of A0-28 amplifiers in B3, C3, RT3

 3b.  ?Replacement of A0-29 amplifiers in M3



     if it ever becomes neccessary, as a service operation, to
     replace the AO-28 pre-amplifier in Models B3, C3 and RT3
     or the AO-29 amplifier in model M3, be sure to follow the
     instructions that are sent with these units.

     They are repeated here for your further convenience.


     ........................................................

When installing unit AO-28 (B3,C3,RT3) set Percussion signal level as follows:

     1. Set Organ 'Volume' tablet to 'Normal' and with all
        other Tablets tilting toward the front of the console,
        press upper manual third 'C' key, pull out first brown
        drawbar and adjust expression pedal so that 2.5 Volts
        (RMS) appears across G-G pre-amplifier terminals.

     2. With same key pressed, push in ?1stDrawbar (brown), pull
        out 9thDrawbar (white) and adjust tone control on
        amplifier so that .5 Volt (RMS) appears across the G-G
        pre-amplifier terminals

     3. Push in 9thDrawbar, set Percussion 'On-Off' tablet to
        'On' and unsolder blue wire from amplifier terminal 'K'

     4. With same key pressed the Voltage measures across G-G
        pre-amplifier terminals should be 3.75 +/- 10% (RMS).
        If is it not, clip out existing resistor inside terminal
        cover on back of amplifier and replace with a different
        value (between 22,000 and 47,000 ohms) to obtain above
        specified Voltage.

     5. Tone control can be readjusted to suit.

     ........................................................




 A0-29

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