OBERHEIM SYNTH

At 04:39 PM 5/30/09, you wrote:
>Hello: at the cost of a small fortune, I've just successfully 
>restored an OBX-A that was left for scrap. My repair (surprisingly) 
>had a backup tape of the presets from another obxa that had come 
>through his shop. Listening to the presents that loaded in and 
>comparing them to the preset chart in the owner's manual shows that 
>most of these are the factory presets (there may be a couple of the 
>other owern's patches thrown in). Here's my issue. for patch A3 and 
>the last two groups (CD and ACD) if I push the patch combinations, 
>different lights light up, indicating to me that the patch is 
>actually loaded and the synth has turned on the various parameters 
>that make up that particular patch, e.g, saw versus other waves, 
>unison or not, s/h or not, etc.--but NO SOUND comes out. What does 
>this indicate? There is something wrong with the memory patch of the 
>synth for those patches? Something else? Thanks in advance for any 
>suggestions.

I can think of a couple of possibilities:
1.  Bad patch tape.  Try programming patch A3 manually (see patch 
sheet here http://www.electrongate.com/obfiles/OB-Xa_patch_A3.jpg) 
and see if it works OK.
2. Bad or missing RAM chip.  Try storing a working patch in the CD 
and ACD banks and see if they stick.

Good luck.

-- Paul White