Keyboard Exchange International
221 S. Magnolia Ave. | Sanford, Fl 32771-1321
Sales Office: (407)323-7493
We Buy Hammond Organs: Dead or Alive
Most Wanted Models: B-3, C-3, A-105, D-152,A-100, RT-3, B-2, BV, BC
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Technical Information for Hammond Tone Wheel Organ
5-50. When a key is depressed, the note first sounds loudly, after passing through the control tube V7, transformer T6, a high pass filter, and terminal D to the grid of V4. Immediately, capacitor C3 1 in the control tube grid circuit begins to discharge, causing the signal to fade away.
5-65. Remove the four screws from the left and right-hand side panels of the music rack. Tilt the bottom of the music rack by lifting the side panels, and remove the rack by pulling outward.
5-66. Remove the 4 chassis bolts (underneath the console) and the 2 machine screws (under the front lower manual rail) that hold the entire manual chassis in place.
5-67. Disconnect the 79 manual leads, 68 pedal leads, 4 ground wires, and the pedal filter leads. The pedal filter is located on the rear surface of the upper manual assembly.
5-68. Pull out all drawbars to position 8, and then tilt the manual chassis from the front as
far as the top of the console will permit. Place suitable wedges or blocks on both sides of the manual chassis to hold it in this position. The manual chassis must be tilted to provide adequate clearance for the bolts in the corners of the main generator assembly.
5-69. Unhook the four suspension springs on which the generator assembly rides.
5-70. Lift up the generator assembly and remove it at the rear of the console.
5-71. Install a replacement generator assembly by reversing the procedure given above for removing it.
5-72. MIXING TRANSFORMER ASSEMBLY.
The Assembly of two mixing transformers is provided complete with all leads to the preset panels, and can be removed as follows:
a. Remove the rear panel.
b. Remove the two screws which secure the transformer cover in place.
c. Label and disconnect all leads from the mixing transformers where they connect to the preset panels.
d. Unsolder green and yellow shielded wires at mixing transformers.
e. Remove the two wood screws which secure the mixing transformer assembly to the manual chassis block.
f. Secure the replacement mixing transformer assembly in place by reversing the procedures given above.
5-73. PLAYING KEY.
5-74. Replacement of playing key on upper manual will be accomplished as follows:
a. Remove the four screws from the left and right-hand side panels of music rack. Tilt the
bottom of the rack by lifting the side panels and then remove the rack by pulling outward.
b. Remove the 2 wood screws and the 2 oval-head bolts from the ends of the drawbar base.
c. Lift and block up the entire drawbar base.
d. To remove a black key, loosen its key mounting screw, unhook key from screw, and lift out key.
e. To remove a white key, loosen its key mounting screw and those of adjacent black keys. Unhook these keys from screws, push them back, and lift out white key.
f. Insert a replacement key and install by reversing the directions given above for removal.
g. Adjust the tension of the replacement playing key by comparison with the adjoining key.
5-75. Replacement of playing key on lower manual will be accomplished as follows:
a. Remove the four screws from the left- and right-hand side panels of the music rack. Tilt the bottom of the rack by lifting the side panels and then remove the rack by pulling outward.
b. Remove the two oval-head bolts from the ends of the stop base.
c. Pull out all drawbars to position 8.
d. Tilt the upper manual as far back as the top of the console will allow, and then wedge or block it in this position.
e. Complete the replacement of the playing key on the lower manual by following the same procedure given above for upper manual keys.
5-76. PEDAL SWITCH ASSEMBLY.
5-77. Replacement of pedal switch assembly will be accomplished as follows:
a. Remove the pedal clavier by lifting it up in front and then pulling straight back. (See
figures l-3 and 3- 1.)
Be careful to prevent damage to the delicately constructed pusher levers (switch
pushers) at the end of each pedal.
b. Unsolder the pedal cable wires from terminals on the generator.
c. Disconnect the brown and black leads from the filter located on the rear surface of the upper manual assembly.
d. Disconnect the orange, red, and yellow pedal signal leads from the resistor strip on the rear surface of the upper manual assembly.
e. Use small wooden blocks to raise and support the entire console a few inches off the floor to provide the necessary clearance for the removal of the pedal switch assembly.
f. Loosen and remove the screws which hold the wiring tube (through which the pedal wiringcable passes to the tone generator) to the console shelf, the 3 oval-head and 1 hexagonal-head screws which hold the pedal switch in place, and the screw which holds the swell pedal rod in place.
g. Lift the cover board and remove the screws which hold the pedal switch assembly to the back rail of the console.
h. Loosen the large bolt at each end of the pedal switch assembly, then remove the nuts
attached to these bolts. Drop the assembly carefully and remove it.
i. Install a replacement pedal switch assembly in place by reversing the procedures above.
S-78. MANUAL CHASSIS.
5-79. Replacement of manual chassis will be accomplished as follows:
a. Remove the rear panel of the console. (Reference paragraph 1- 10.)
b. Remove the four screws on the left- and right-hand side panels of the music rack.
c. Lift the side panels to tilt the bottom of the rack, and then remove the rack by pulling outward.
d. Remove the 4 chassis bolts (under the con-sole) and the 2 machine screws (under the front lower rail) that secure the entire manual chassis in place.
e. Disconnect all preamplifier leads.
f. Loosen set screw in expression control lever arm and detach arm from preamplifier.
g. Remove preamplifier from shelf after taking out mounting screws.
h. Unsolder (do not cut) the 79 manual leads, 2 ground leads, 3 pedal signal leads (red, orange, and yellow), and the pedal filter leads (brown and black).
i. At the power terminal panel, unsolder the live wires leading to the manual chassis start and run-motor switches. Determine these leads by tracing the leads from the switches.
j. Detach pilot lamp bracket by removing two wood screws.
k. Unsolder eight scanner wires from terminals on back of drawbar base.
1. Unsolder brown wire from vibrato line.
m. Tie the disconnected cables to the chassis to prevent damage to the other console components when the manual chassis is removed.
n. Remove the manual chassis through the rear of the console. Slide the chassis out carefully.
Because of frame construction, the chassis will drop suddenly before it is entirely out of the console. Two men are required to remove the manual chassis from the console.
o. Install a replacement chassis by reversing the procedure above. (See Figure 2-2 for cable connections).
5-80. SWITCHES FOR START AND RUN MOTORS.
5-8 1. The switches for the start and run motors are both mounted on the same metal plate; the following replacement instructions are equally applicable to each:
a. Remove the black bakelite switch handle by unscrewing it in a counter-clockwise direction.
b. Remove the round knurled nut which holds the switch to the metal plate.
c. Remove the four oval-head screws which hold the switch plate to the music rack.
d. Remove the rear panel of the console.
e. Unsolder the leads (from the defective switch) at the power terminal panel on the generator. (See figure 2-l .) One lead (black) is wired to the start switch. Four leads, 1 yellow, 1 black, 1 blue, and 1 brown, are wired to the run switch. (See figure 4-l .) Unscrew or un-solder jumper wire between switches.
f.. Remove the tape which secures the wires together. Unbraid the wires connected to the
defective switch up to the manual chassis so that the switch can be removed.
g. Pull out the switch. Note the position of the switch with respect to the color of the wires so that the replacement switch will be installed in the correct position.
h. Install the new switch in the proper position. Braid and tape the wires carefully so that they will not interfere with the operation of the generator run motor.
i. Solder the leads of the replacement switch to the power terminal panel.
j. Operate the switch to determine that it has been installed properly.
k. Replace the rear panel.
5-82. START MOTOR (See figure 5-3).
5-83. Replacement of the start motor will be accomplished as follows:
a. To make the start motor accessible, follow the procedure for removing the main tone generator. (Reference paragraph 5-63.)
b. Remove start motor capillary threads from oiling trough.
c. Disconnect the leads to the start motor at the power terminal panel on the generator.
d. Using a socket wrench, remove the two start motor mounting screws.
e. Secure a replacement start motor in position by reversing the procedures above.
5-84. RUN MOTOR AND VIBRATO SCANNER ASSEMBLY. (See figure 2-l .)
5-85. Replacement of run motor and vibrato scanner assembly will be accomplished as
a. Remove the rear panel.
b. At the power terminal panel on the generator, unsolder the red and black wires which lead to the run motor that is to be replaced. (See figure 4-l .)
c. Unsolder 7 scanner wires from terminals on back of stop base and 2 scanner wires from line box.
d. Remove shielded lead attached to "SCAN" at preamplifier.
e. The running motor is secured by four machine screws to the generator frame. Remove
the nuts and lockwashers, and then disengage the flywheel coupling springs.
f. Remove the entire motor and scanner assembly by means of a gentle pull.
g. Secure a replacement motor and vibrato scanner assembly in place by reversing the procedures above.
5-86. TONE GENERATOR FILTERS.
5-87. Filters used for frequencies numbered 49 to 91 inclusive, as referenced in paragraphs 5-9 to 5-l 1 inclusive, are resonant reactor-capacitor units, and will be replaced as follows:
a. Unsolder all leads.
b. Remove the two screws holding the filter.
c. Remove the component.
d. Replace the component by reversing the procedures above.
221 S. Magnolia Ave. | Sanford, Fl 32771-1321
Sales Office: (407)323-7493