Vintage Synth Repair

i put in those two 15 pf caps and it fixed the cutoff problem. just
thought i'd let you know! looks like i wont have to adjust the trim
pot yet. 

i just noticed that when i play a low note and hold it down and then
play a high not above it to steal the note it just retriggers the same
note. when i play and hold a high note and then play a low note it
switches notes. (this is with only one oscillator turned up.) 

is that the way it's suppose to be?

--- In vintagesynthrepair@yahoogroups.com, "cockandswan"
<cockandswan@...> wrote:
>
> thanks a lot! so i already went out and got two 15 pf caps to replace
> the 30 pf cap (you can do that right?) 
> 
> do you know if they'll be any negative side effects of adjusting that
> trim?
> 
> thanks for the advice, i'll let you know how it goes! i think i better
> do the test points next...
> 
> -johnny
> 
> 
> --- In vintagesynthrepair@yahoogroups.com, Malte Rogacki <gacki@>
> wrote:
> >
> > > i didn't even realize it but "c2" the capacitor hooked to pin 1
and 8
> > > of the op amp is totally broken. classic newbie move i guess.
fix one
> > > problem and cause two more. so now i'm looking in the user
manual and
> > > i don't see a value for that part in the parts list of board C-1. do
> > > you happen to know what the value of that component is?
> > 
> > http://en.wikipedia.org/wiki/Opamp#Class_A_gain_stage
> > 
> > If you're using a modern internally compensated opamp this capacitor
> might
> > not even be needed; however if you're using a LM301 like in the
> original it
> > is 30pF as indicated on the schematic. Because this is a "standard
> value"
> > as described in the wikipedia link it is probably not in the parts
list.
> > 
> > I don't think this should cause this behaviour, though.
> > 
> > There are a few other points but you might first want to check out the
> > voltage on pin 3 and 4 of the filter module. Pin 3 is the output
of the
> > opamp (and hence the various modulation sources), pin 4 is the cutoff
> > slider.
> > There's also a trimmer (T3) that is used to fine-tune the cutoff
> frequency;
> > if that one is completely out of range it might affect the
frequency as
> > well.
> > 
> > I'm working on a Odyssey Mk3 at the moment myself.
> > 
> > 
> > -- 
> > Malte Rogacki gacki@
> >
>
----------------------------------------------------------------------------
> > "Don't forget to TURN ON THE SYNTHESIZER. Often this is the reason
> why you
> >  get no sound out of it." (ARP 2600 Owner's Manual)
> >
>
----------------------------------------------------------------------------
> >
>