From Andre Majorel Sent Thu, Apr 12th 2018, 16:28
From Andre Majorel Sent Thu, Apr 12th 2018, 16:28
On 2018-04-12 09:09 -0400, Chase Smith wrote: > Although the ms-20m is smd, it is actually pretty easy to work on bc > there is a lot of room in there. Some pads are left open for adding > stuff like vco1 mod input. I was able to add independent cv for both > oscillators, disconnect the eg from the vca and some of the usual > mods. I like it a lot for the sound and the form factor, but I've > never used an old ms-20 so I can't say how close it is. Someone took > a lot of high res photos of the pcbs and I saved them to my dropbox, > if anyone wants to take a look. > > https://www.dropbox.com/sh/7qt7tcachqs7w8f/AACbLQ2RQgyRSuB8pLut4JCOa?dl=0 Very interesting, thanks. In Korg_MS-20M_PCB_060.JPG, you can see the VCFs. I suspect that the two rows of four transistors are for the KORG35 but that's odd. The schematics of the KORG35 I've seen showed five transistors. The six NJU7301 (quad analogue SPST switch) are probably there to share the I/O and controls between the two versions of the filters. -- André Majorel http://www.teaser.fr/~amajorel/