Hammond Model A, Manual, Page: 274 / 298

3-19. Repeat the procedures of paragraphs 3-15 to 3-18 inclusive, on the lower
manual. Use the No. 1 brown and No. 9 white drawbars in the first set of drawbars in
the right-hand drawbar group.
3-20. If all notes are uniform in intensity or change evenly from note to note, the
tone generators are operating normally. However, if notes are weak or absent,
proceed as directed in paragraph 3-21.
3-21. CORRECTION.
3-22. A single dead or weak note which occurs on one manual but not on the other,
may be caused by a fault in the key contacts. To correct this fault, adjust the bus
bar shifters associated with the pedal switch and both manuals as directed in
paragraphs 4-9 to 4-13 inclusive.
3-23. A single weak or dead note occurring at the same point on both manuals may be
caused by a defective generator, a broken wire, or a poorly soldered joint on the
terminal strip. Test the generator for output by fastening a short length of wire to
the 6th busbar, from the bottom, on the preset panel; then touch the other end of
the wire to each lug on the generator terminal strip. If all notes sound. the cable
wire or soldered joint is at fault and must be repaired. If no generator output
exists. either the filter circuit or the magnet pickup coil may be defective. or the
tone wheel is not rotating.
3-24. Figures 5 & 6 in the Main Generator section illustrates the position of each
filter reactor and capacitor on the generator cover. Fasten a short piece of wire to
the 6 busbar from the bottom, on the preset panel, and test each terminal of the
th
filter. (Reference paragraph 3-23.) If the filter is at fault, replace the defective
component as described in paragraphs 5-86 and 5-87.
3-25. If there is no signal across the magnet pickup coil terminals, even with the
coil disconnected, either the coil is defective or the associated tone wheel is not
turning. Check the pickup coil by unsoldering its lead and, with a short piece of
wire, connect the lead to the preset panel. (Reference paragraph 5-6.)
3-26. When there are two dead notes on each manual, determine which frequencies are
at fault, as described in paragraphs 3-14 to 3-20 inclusive. Figure 4 in the Main
Generator section illustrates the exact location of the magnet associated with each
frequency; the dotted lines connecting the frequency numbers indicate that they are
generated by two tone wheels on the same shaft and in the same compartment. (It
should be noted that with few exceptions, tone wheels on the same shaft differ in
frequency numbers by 48.) On frequency numbers 37,38, 39,40, and 41, only a single
active tone wheel is on each shaft. If the 2 magnets associated with the dead notes
are together, 1 tone wheel is probably jammed against the magnet tip. To correct
this condition, proceed as follows:
a. Loosen the set screw on the magnet to be adjusted, then move the magnet
back slightly. Do not twist it.
b. Strike the proper playing key. The note should now sound.
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