Hammond Organ Service Manual - Early Models (A,B ... - Audiofanzine

There are several types of generators in use and the foilo\^^ing
1 to 9.
information
will aid the service technician in identifying the console on which work is
being performed.
91 Frequency Generator
Model A serial No. 1 2676
Model D serial No. 1
3143
Model B serial No. 4000 - 10, 549
Model E serial No. 8000
8663
Model C serial No, 1 1247 Player consoles
serial No. 9000 9Z09
The number of tone wheels on the above models is 91, and 5 blank wheels
are used to maintain the balance of the rotating units. There are twelve
wheels with two teeth, one to operate at each of twelve speeds, and
similarly twelve have four teeth, twelve have eight teeth, twelve have
sixteen, twelve have thirty-two, twelve have sixty-four, twelve have one
hundred and twenty-eight and seven have one hundred ninety-two. An
assembly with a two-tooth wheel also has a thirty-two tooth wheel which
generates a frequency four octaves above the other. The four and sixty-four
tooth wheels go together, as do the eight and one hundred twenty-eight tooth
wheels. The twelve sixteen tooth wheels are mounted with seven one hundred
ninety-two tooth wheels and the five blank wheels. In this last group the high
frequency is not four octaves above, but is four octaves less five semi^tones
above the lower.
This arrangement gives a total of 91 frequencies that are connected to
corresponding terminals on the generator, and then to the manuals and
pedal switch. In all cases, as mentioned above, the generator must be
used with corresponding manuals and pedal switches and other types of
generators cannot be substituted.
82 Frequency Generator
Model A serial No. 2677 2711 Model D serial No. 3144 17, 074
Model B serial No. 10, 550 - 17, 074 Model E serial No. 8664 8739
Model C serial No- 1248 - 17, 074 Model G serial No. 4101 7349
Player consoles serial No.
9210 only.
In the above consoles, frequencies #1 to 9 have been omitted from the
generator, and only 82 generator terminals are used. Similarly, there are
only 82 tone wheels and magnets in the generator instead of 91- Blank wheels
replace the nine two-tooth tone wheels formerly used to produce frequencies
This generator change accompanies a wiring revision in the manual and pedal
switches which makes the frequencies from 1 to 9 unnecessary. Generators
having but 82 frequencies are easily identified by a blank space on the terminal
strip at the left of the ground terminals* The first terminal at the left of this
space is terminal #10.
91 Frequency Generator with Cornplex Tone Wheels
Model BV serial No. 17075 - 29737
Model CV serial No. 17075 302S7
Model RT serial No. 1001 1201
Model B-2 serial No, 35000 - 40303
Model C-2 serial No. 35001 - 40459
Model RT-2 serial No. 1300 - Z150
in the above consoles, the original two-tooth wheels in the generator have been
replaced with twelve two-tooth com^^lcx tone wheels, which supply a fundamental
tone that is enriched with the odd-number harn:ionics. Both manuals
and pedal switch are wired differently and are therefore not interchangeable
with earlier models. 2-11