Vintage Synth Repair

Hi,

does anyone have any tips for doing this?  or schematics?

Thanks,
Ian

> 
> does anyone have any tips for doing this?  or schematics?
> 
> 

I've got a SH-1000 & the schems.
I'm pretty keen to get it CV'd up to, but i've been so busy with other 
projects.
I'm not 100% sure, but it's my understanding that the SH-1000 is 
1.2volts/octave, So if we want to interface it with the real world or 
standard 1v/oct synths, will have to put in a scaling buffer???

Any thoughts?

Mike

>>I'm not 100% sure, but it's my understanding that the SH-1000 is
1.2volts/octave, So if we want to interface it with the real world or
standard 1v/oct synths, will have to put in a scaling buffer???<<

that's absolutely right. I've seen a schemo for this somewhere too, on
the interweb..... the oscillator in the sh1000 is set up to run at
1.2V/octave for some reason, & it would be a tricky job to rescale it
& have it track at 1V/oct. I can't remember why, but it's to do with
the way the design achieves linearity over several octaves, & diode
voltage drops, that sort of thing. I'll dig out me schemos in a bit.

but a simple op-amp buffer would be a good idea anyway. you could then
use trimmers to adjust scale & offset (tuning). 
the best place to introduce the external CV would be somewhere around
the random-note switch. you'd have the option then of leaving the
keyboard connected (to transpose the incoming CV) or not.

I'm reasonably sure it's the same story with the sh2000 & the sh3/3a.
I have not recently tried with any of the trio, though my 3a had
CV/gate inputs already fitted when I got it. it tracked fine with an
arp 1613.

duncan.