OBERHEIM SYNTH

I'm somewhat of a novice so forgive me if my questions seem "ignorant". 
I bought off Ebay quite awhile ago an Oberheim OBX-a. I got it cheap 
because the seller said it was "dropping a sound". Not knowing any 
difference at the time, I thought it would be cool to have a vintage 
synth to "restore" as a project. Well, due to several unforseen 
situations, I wasn't able to get on the project so I put it off for a 
year. As I researched, I found the contacts needed to be cleaned & the 
keys leveled, among other things. Since my time for this was not going 
to be like I thought, I decided to take it in to a repair shop in L.A.. 
   It took quite a while but the repairman said it was missing a voice 
board. To get all the work done, he wanted nearly double what I even 
paid for it so I decided to pass on getting the board for now. So now 
it's a 7 voice synth. I had the contacts cleaned anyways and I will be 
picking it up this week(minus the missing board). 
   Here goes the questions: Are all the voices the same? If not, are 
they numbered or named so I know what to get? Does anyone on this list 
have any boards available to sell? Is this even worth my time to do 
this? If anyone has done this in the past, please help if you can & 
thanks for all your help in advance!