Last Updated:
KORG MS-20 (Midi-fied)
MODS - Rear Panel & Switches

| Synth Index | Korg MS-20 | MS-20 Mods1 | MS-20 Mods2 | MS-20 MIDI | MS-20 Midi Clock |

| Rear Panel  | Some Handy Switches|


Rear Panel: IEC Mains Plug / Back Panel Jack Sockets / Midi Sockets

Well, it came with a flying lead that comes out of a hole at the back panel. I hated it.
So the 1st thing I do (normally to most stuff with flying leads) is to cut the lead up, and install an IEC Mains socket so I could use standard IEC Powercords.
To make the IEC Mains Inlet hole, I use a screwing hand tool, which is an M10 Radius Hand Hole Cutter, 28x21mm (
RS Cat.#543-614 or or 541-501), with matching 10A Snap In PCB Mount IEC 320 Plug Socket (311-8031 or 488-191).
I also took the time to drills some more holes to bring and tapped some Jack Sockets to the back - since there are some connections that i normally don't like cluttering up the front jack panel (e.g. Signal Out)

From Left to Right, they'd be:

IEC Mains Plug


AUDIO IN (tapped to Signal in to ESP)

6 sockets to handle some OUTPUTS:
- Kbd CV OUT
- Kbd Trig Out
- Mod Wheel
- Mod button
- ESP CV Out
- ESP Trigger Out.

Dunno why I tapped these to the back - just thought, there might be a day i need to control external stuff with the MS, so it's a think-ahead type. But at least, if i want the CV/Gate from the ESP to control other stuff, i dun have to plug things on the front.
6 sockets to handle INPUTS:
- Proper V/Oct CV In
- Gate Trig In
- Hz/V CV In
- Total In
I kinda ran out of space but still wanna add sockets to tapped to the CLOCK IN and also the extra PWM In, so they go above the 6 input sockets, well, obstructing the warning notice (non english parts).

- Midi In & Thru
- Midi Clock Thru S-Trigger Pulse plus a DIN Sync Thru!

OK, the labels look crap, but what the heck....

When I soldered the wires, one end tapped to the PCB Sockets, the other end, i used connectors, some 2 pins and some 6 - 8 pins, so that the wires could be removable if i need to work on the PCBs later:



Some Handy Switches
Modders always like putting toggle switches. Some people think it's unprofessional but I don't.
Switches are there for simplicity's sake - and they do handy simple jobs.
Well, the Mod Wheel area seems very nice for switches:

1st one is easy, but also not as useful:
I just put a switch which shorts the Mod Button permanently. You never know when you'll need to use the mod button, and maybe there are situations that it needs to be pressed down for a longer while other than short presses, and this switch would then become handy.

This is probably the most useful switch. I always do this switch mod if possible.
There are so many cases where you have to hold down 1 key on the keyboard for a long time, e.g. when doing External Audio Input Filtering, you have to hold a key so that the trigger would allow the Ext Audio to pass thru. I hate masking taping a key.
So what i did was hook up 2 wires to the keyboard PCB, and use a switch to short a key. It's easy to find where to solder the wires to - just use a multi-meter to see when u press a key and which terminals conducts. So I did this and a switch is wired to short the key C2. Mounted above the Mod-Wheel:

Actually i wanted to do 2 switches, but there wasn't enough space, as I have put a connector to simplify plugging and unplugging the mod-wheel when opening up the MS-20.



Next: CV Mod, PWM Input


Home Synths

MS-20 MS-20 Mods1 MS-20 Mods2 (CV) MS-20 Mod3 (Midi) MS-20 Mod4 (Sync)