You bought the one from "Z"

On Dec 30, 2014 9:09 AM, " isatellite@... [oberheim]" < oberheim@yahoogroups.com > wrote:

 

Just bought an OBXa this past week (in mint condition) and it arrived with a couple of voices switched off and not tuning properly. I went through the voice card calibration procedure and now all 8 voices are calibrated properly and don't fail during autotune. But I have discovered a couple issues since it arrived:

ISSUE 1:

In standard (non-split, non-double) mode, with all buttons turned off in the performance section, frequency depth will modulate VCO1 on all 4 lower voicecards, even if the VCO1, VCO2, FILTER buttons are turned off in the modulation section. Modulation should have no effect if the buttons are turned off in this section.

ISSUE 2:

I can't seem to get the transpose standard to be an octave above the transpose down in the performance section. Can't get this to calibrate properly.

ISSUE 3:

The performance section OSC2 sync button, when engaged, causes the pitch to slightly rise, and VCO1 and VCO2 beat against each other. When disengaged, everything is normal.

ISSUE 4:

In the performance section, it's very difficult to get the Center Lever adjustment pot to match the Narrow Bend pitch. I can get close, but not 100%. Is this typical

ISSUE 5:

The pots on the voice cards are really hard to set VCO1 and VCO2 initial frequency. I'd like to replace the 16 tuning pots on the voice cards with Bournes pots. This was done to my OBX and it is now much easier to calibrate. Anyone have a link to a recommended pot that would work

Any help with the above issues would be much appreciated. I'm somewhat familiar with these synths (I also own an SEM, OBX (for nearly 20 years now), and an OB8) and have a lot of experience doing basic calibrations on Oberheims through the years. The OBX is similar to the OBXa (calibration-wise), and that synth has been a labor of love.

Thanks in advance!