Vintage Synth Repair

Hello,  I have a crumar orchestrator that is in tune with itself, but which cannot be tuned to other instruments.  While there is a pitch slider on the front, it cannot go flat enough to put it properly in tune with a standard tuning.

Could anyone please point me to the proper adjustment point inside the synth so that I can realign the center of the pitch slider such that it can make useful adjustments? I'm a bit new at this...

I have uploaded  a PDF of the schematic to the Files folder on this group page.

Thank you!  DT.

Your tuning issues are most likely due to components drifting over time. 

I'd start by checking the voltages coming off the power supply (lower left hand corner on page three of your PDF). The synth is due for a recap if one hasn't already been done. At the very least, I'd replace the power supply filter caps and possibly those big 2W power supply resistors. Once your power supply is in spec, you can reevaluate your situation.

--- In vintagesynthrepair@yahoogroups.com, "scituate_mass" <sneakyflute@...> wrote:

>
> Hello,  I have a crumar orchestrator that is in tune with itself, but which cannot be tuned to other instruments.  While there is a pitch slider on the front, it cannot go flat enough to put it properly in tune with a standard tuning.
> 
> Could anyone please point me to the proper adjustment point inside the synth so that I can realign the center of the pitch slider such that it can make useful adjustments? I'm a bit new at this...
> 
> I have uploaded  a PDF of the schematic to the Files folder on this group page.
> 
> Thank you!  DT.
>

Oddly enough, the synth is now in tune.  I had it open to replace some  
of the broken control sliders - when I powered it up, the tuning issue  
had vanished.  Weird.  But I will take your advice and do the recap as  
well. Thanks so much for your help!