OBERHEIM SYNTH

Sounds like the patch storage RAM is not working somehow.  Could be an 
address line , a data line, or possibly a bad RAM chip.   Probably an easierway to find the frequency of the clk is to simply locate the crystal.   Thefrequency is usually stamped into it.  There is probably only one crystal,and it should be pretty close to the Z80.   The Z80 clock should be half of 
that rate.
You can try removing any chips that are socketed having to do with the 
patch RAM and then plugging them in again.   Actually, you can just pry 
one end up maybe 1/8" or less with a small screwdriver, then push back 
down again, then do the other end.   Just a little motion relative to the 
socket tends to clean the leads, in case they aren't making good contact.Ground yourself by touching the metal inside the case before doing thisso you don't make a spark from static/ESD.
   Bob

      From: "richtrix@... [oberheim]" <oberheim@yahoogroups.com>
 To: oberheim@yahoogroups.com 
 Sent: Saturday, March 7, 2015 1:13 AM
 Subject: Re: [oberheim] Finding Clock frequency of my OBXa