[sdiy] Memorymoog VCO trim

[dragon.servicing]

Hi,
I think I read a while ago that the trimpots in the Memorymoog ( and 
some other older synths ) can wear out causing unpredictable 
performance. I did find this with a Minimoog I worked on a couple of 
years ago. ( but the trim pots are probably a different type ).
I think it was on the Memorymoog that the power supply trims were not 
ten turn pots but had to be set very accurately ?
  hopefully someone else can confirm this....
regards Peter


Barry Klein wrote:
> Hi all,
> I have been occasionally working on the MM+ I just purchased.
> Trying to get 6 tuned oscillators but only get 5.  When I go back to check
> usually I find one that is off by >2 digits from 7F.  Is that what would
> cause the tune failure or something else?  The oscillator that is off is not
> consistantly the same.  I also see a problem where every 6th note does not
> play in this test state.  
> 
> This is the 3rd MM I have worked on and (as before) the trimpot adjustments
> are damn touchy.  So much so that I wouldn't want to even bump one that was
> tuned....
> Is this due to old trimpots - do new ones make life much easier here?
> Anyone tried installing digital pot IC's?
> What improvements have you made to your MM's to either make calibration
> easier and more stable or even just mods you have made to increase
> capabilities?
> 
> Barry
>