OBERHEIM SYNTH

I have done it without any testgear at all, but if you don't have a good ear, you're in for a rough ride.
The pulse width adjustments and tracking are particularly hard, and there are many interactions of course.
It all hangs off the accurate adjustment of the power supply as mentioned above, and the bender wheel adjustment is crucial. 
Previous answer is the correct one, do what they did at the factory, if you can get the info.
At the time I did it, the info wasn't easily available, and I'd done my OBX a short time before, so felt confident.
Mistakenly some might say.  : o





On Tuesday, 7 January 2014, 12:34, James <fl_799@...> wrote:
 
  
Walter,

First, download the 1st and 3rd edition of the service manual. First edition is here:

http://launch.groups.yahoo.com/group/oberheim/files/OB-xa%20files/

3rd edition: http://www.synthfool.com/docs/Oberheim/Oberheim_OBXa/oberheim_obxa_service_manual_3.pdf

You don't need a scope to tune the boards. It is very straight forward if you follow the manual. 

To do this right, you need to perform the full service. The 5 and 15 volt piece always comes first followed by all of the adjustments on the bender assembly. Once those are finished, then you tackle the cards.For your first time, you might want to plan on 2 hours for the whole calibration. 

James




________________________________
 From: walter bonacci <walterbonacci@...>
To: oberheim@yahoogroups.com 
Sent: Tuesday, January 7, 2014 5:51 AM
Subject: [oberheim] Oberheim OBX-a voice tuning specifics
 


  
Hi,

Someone has the specifics for the voice of an oberheim obxa?
I would like to know which trimmer does what.

In theory is it possible to do the tuning by hear and without an oscilloscope?

Thanks,
Walter