OBI expander

[BJ]

Paul Schreiber wrote:

> pinging AH has shown there is a LARGE interest in cloning the Oberheim Expander. After looking at the
> schematics, the design is:
> 
> a) very clever, esecially the filter (which will wind up as a module!)
> b) the processor section can be replaced easily (actually kind of dorkey)
> c) forget the SW envelopes, use 3310s.
> d) forget all that muxing of control voltages, use quad DACs.
> e) heave the VF displays, use LCD
> f) keep all the rest
> 
> If anybody wishes to help in the controller code (probably use an Intel 251 or a Siemens 166) let me know.
> 
> I want to thank everyone for their support and here's to the future of DIY!
> 
> Paul Schreiber
> Synthesis Technology

A wery interesting project i suppose,but i do have some things on my
mind!

Wasn't the cpu a 68B09 in the Obie Expander?
If not, there would be a lot of reprograming if you are going to use
another cpu?
And this could be a great hassle  depending on the arragement of the
software.
Particulary if you going to replace som SW parts fore HW parts and 
some major change in the HW aswell !!

My reissue of that machine would to keep as much as possible of orginal
design
and or to replace as much as possible without any reprogramming.
replacing the VF display to a LCD would be a major advantage.

Do you going to do the front panels aswell, and do the OBexpander use
1 turn potts or  rotary encoders or peerhapps stepped potts
i do remember it have a clicking action of the potts!
And how many complete units do you think you can make!
I would buy 1 directly if a nice front panel could be made available.

BJ in volvo land.....