View Full Version : Gulbransen transistor oscillators
04-15-2006, 06:01 PM
Ihave 12 Gulbransen oscillator "modules" that came out</P>
a model G-3 spinet. Each "module" contains 6 octaves of each note.</P>
I've been trying to decode these oscillators for awhile now </P>
with no luck. If anyone has any idea how to get these oscillators</P>
working or maybe has some schematics or some similar</P>
schematics.... your help would be greatly appreciated.</P>
05-23-2006, 02:04 AM
i have the service manual for the gulbransen 600 series (a 2 by 61 note
manual, 25 pedal console). the part you mentioned in my service
manual is refered to as the tone generator. if i had access to a
scanner, i would be able to send you the appropriate pages, even though
these are not your specific model.
to start off, the 600 series tone generator assemby part number is 407064 which is printed on the board.
and the accompanying test is as follows:
<blockquote>The Tone Gernerator consists of a high frequency oscillator, a Top Octave Synthesizer and twelve seven stage dividers.
C1 and L1 are tuned for transistor Q1 to oscillate at approximatel 2
MHZ. Transistor Q2 functions as a buffer amplifier and drives
IC-1, the Top Octave Synthesizer. Ic-1 divides the 2 MHZ input
signal and produces the 7th octave pitch of each of the 12 notes in a
scale. In addition, the C pitch 8th octave is available at pin 15.
IC-2 thru IC-13 are identical 7 stage binary counters. The 7th
octave outputs of IC-1 drive the binary counters, producing outputs for
octaves 6 thru 0 for each note, and appear at the output connection as
the 7th octave output. These outputs are inputs for the gate
i am sorry i cannot supply pictures and schematics, and as it is not
the same organ, this might only be of limited help, but it might give
you a clue for your work.
best of luck
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