You got an Omnichord too? Great! And it´s got only this one, pretty cheasy sound, well...
there is a lot you can do to improve the sonic qualities of your instrument and explore lots of new sounds and possibilities.
bend your
Omnichord today!
turn your
OM-27 into a
shiny beast of
sound
For the first steps you only need a Phillips srewdriver to open it, two miniature srewdrivers to access points on the circuit boards, and a external battery. NEVER USE A POWERSUPPLY WHEN TOUCHING THE CIRCUIT BOARDS !
The OmniConcertino
explained
You can also use your fingers, to touch areas instead of individual points. Generally, points on the main-board, where the chords and strumbar sounds are generated, are fed into the drumsound generation part on the halfround control-board.
the functional areas
of the FrankenChord
Check out these pictures to get an idea where these points might be. Find your own hot spots!
the body-contact points
on the OM-27 control
circuit-board explained
THE SAFETY RULES
before you even think of opening any device:
Do NOT
connect it to a powersupply, use internal or external batteries instead.
This is substancial, don´t risk your life! If you want to connect
to external gear use also a D.I.-box. Again, these are absolutely necessary
safety rules.
When you connect points on the circuit-boards, especially with two hands,
electricity will travel through your body (very little though). Think
about that, it´s at your own risk.
the body-contact
points on the
OM-27 control
circuit-board
explained
Thanks to Rob Hordijk I now got the description of the main chip of the OM-27. It was only used in this model, later models, like the OM-36 and OM-84 have a different chord generator and control-chip (M50740-701SP and M5M82C54P-6). If you happen to have any information on these chips, please contact me.
description of the
OM-27´s chord generator
AY-5-1317A
There are two different keyboard matrix layouts provided. Both use all twelve keys of the chords. Why does the Omnichord only have 9 keys? Have the circuit designers messed up? Is it on purpose based on statistics that show that the missing keys almost never apear in popular music? Who knows...
I got the chip layout just recently, time will show what silly things can be done to the chord management.
two keyboard-matrix
layouts for the
OM-27´s main-chip
AY-5-1317A