[HAM] Generator callibration device?

[Kon Zissis]

Hi everyone.
In the 10 minute  Hammond factory film from the mid/late 1950's that is
on the internet briefly shows a woman  matching the capacitors to the
inductor filter coils and then it briefly shows a man calibrating the
TG.
 
The woman is using the "automatic condenser selector" which is a device
which is placed over the inductor and then the women looks at and makes
an adjustment to the electronic meter which is to the left of the TG and
she then picks a wax paper capacitor  from one of the capacitor bins. 
Without knowing anything about this device I assume that it might be
some kind of oscillator or some kind of capacitor/ inductor peak
resonance indicator.
 
The man who is calibrating the TG has some kind of  device placed on the
magnet rods and this device looks like a short rod with a turn screw
wheel at the end and I assume that as the turn screw wheel is turned, an
internal rod slowly pushes the end of the pickup rod so that it gets
closer to the tone wheel until the electronic voltage meter produces the
correct output voltage reading. The man is not shown  tightening the
pickup magnet set screw. 
 
This raises an interesting issue.
In my experience with recalibrating the TG's I have noticed an annoying
problem in that the pickups rods ( especially of the upper midrange and
the treble tone wheels ) often move slightly when the set screw is
tightened thus changing the output level of that TG note, sometimes up
to plus or minus 10 millivolts peak to peak so therefore I have to
untighten  and then reset the pickup magnet rod again until the desired
output level is produced after the set screw is tightened. Because of
this problem it can take me  up to seven or eight hours to precisely
recalibrate the whole TG.
 
The man is not shown tightening the set screws , he just adjusts the
next  pickup rod whilst observing the output voltage meter. From this I
assume  that he tightened the set screws later on. Knowing that the
pickup rods can move slightly when the set screw is tightened this might
then explain why each stock unrecalibrated  TG ( either with correct
spec new capacitors or with red  mylar capacitors ) has slightly
different output levels and some TG notes are noticeably louder or
weaker  than the adjacent TG notes and thus need to be reset to produce
a proper normal output level.
 
Three people who would know "how it was done " at the factory  are Al
Goff whose father worked at the Hammond factory and Al himself worked
there for a while , and Mike Fulk and Sal Azzarelli who were given
factory procedure documents by the Hammond chief technical engineer Alan
Young.
 
One interesting discrepancy is that Al Goff has written that the factory
TG output curve was changed a number of times during the different
production runs whilst Mike Fulk was told that the factory TG output
curve was only changed once throughout the 40 years of TG production. A
technical document by Alan Young from 1969 mentions that the factory TG
output curve was changed in 1956 " for the convenience of the factory
test procedures".
 
I have the measured TG output curves of over seventy organs ranging from
organs of all eras of the TG production  including  wax capped ,
recapped and red mylar capped organs, and with all this data I can see
five distinctive  differences in the TG output curves , the first being
the recapped very early Model A and BC organs whose whole TG output
curve  had lower output levels compared to the 1940's to 1970's TG's.  
 
The recapped TG's of the 1940's and up to 1956 had an approximately
similar output curve and then the TG's built after 1956 and up to the
1970's had a similar output curve. The pre 1956 TG curves had noticeably
louder levels  for pedal bass  TG notes 1 to 12 and slightly louder  TG
notes 13 to around 40 when compared with the TG output curves of the
post 1956 TG's.
The earlier T-series spinet organ TG's have very loud upper midrange and
treble TG note levels but the later T-series organs have TG output
curves similar to that of the post 1956 TG output curves .
Finally the H-100 organs had TG curves similar to the post 1956 organs
but the output levels of the TG notes  86 to 96 are extremely higher .
 
All the best.
Kon
 
Alan Lenhoff and Scott Hawthorn wrote:
>It always amazes me that people are still
>debating how Hammond callibrated its tone
>generators. Given that they stopped production
>less than 35 years ago, you'd think *someone* who
>worked in the factory would still be around to
>explain the process and let us all know how to
>take a bag of cheap caps and restore all our
>Hammonds to their original specs quickly and
>reliably.
 
You would think. I wonder if those employees had to sign some sort of 
disclosure agreement, and are still taking it too seriously after all
these 
years.