OBERHEIM SYNTH

I have an OB-X and have gotten it back to life many times.

First, your memory battery likely went dead. If the board still works
(you can program it by turning knobs/button pressing) you will likely
need to change the battery. With the battery out, check the resitance
and make sure the battery is seeing M-ohms.  If not, you have a
capacitor that shorted out, and you will need to track it down or the
replacement battery will go dead in a few weeks.


If the board does not work 
1)Double check to make sure all the voltages on the power supply are ok.
2) Remove all voice cards and power it up. See if it looks like it is
working (i.e. light turn on and off correctly/it will let you store
patches.
3) If step 2 is ok, power down,insert a single voice card and see if
it works.  Put the board in Unison so the voice triggers each time you
hit a key.  If that voice works, power down, take it out and put it in
the "good" stack.
4) If all voices work, or none of the voices work it is guess work
time.  I have gone through and replaced just about all of the blue
Tant capacitors on every voice and on all the monther boards.  If you
still have these, it is only a matter of time, they will fail and they
can cause very big problems. I strongly suggest you change out all of
them on power supply, and on each voice board there are several right
next to the voltage regulators.  At a minimum, change these out.

Good luck and let me know what happens. 


--- In oberheim@yahoogroups.com, "jahg88" <jahg88@...> wrote:
>
> Hi All.Have a OB-x that worked great the last time I used it two yrs. 
> ago.Now when turned on,random lights come up.I have the  service 
> manual.Power supply voltages ok,Clk,address and data busses are up and 
> running.I am analyzing the schematics today.Any ideas out there?
>                Thanks 
>                 Jim
>