Hi folks,
Some time ago I bought an MS404 on Ebay Germany and was surprised when
it turned up as it looks a little different to the ones I'd seen in
pictures. I think it's an early version, it has the pots mounted on the
front panel then wired up to the main board which sits at the back of
the case.
The circuit board is dark brown and has no printed markings, making it
difficult to identify the trimmers.
I have the following instructions to set the VCO scale (translated by
Google!):
The device should be before this adjustment is already about 30 minutes
into operation in order to exclude subsequent variances.
* 1 MIDI Referenzton of MS-404 to make C1 (MIDI code 36)
* 2 P2 (Tune on the front panel) and P18 (VCO high end trim) in
middle position.
* 3 The VCO with a P17-Scale initially grossly einjustieren so
that the game on the MIDI keyboard connected Oktavsprünge on MS-404
really played (at the keyboard Oktavsprünge have a frequency doubling
effect of VCOs).
* 4 Press F3 (F 2 1 / 2 octaves above the reference C). VCO
frequency with P16 (VCO offset) to 174.6Hz einjustieren.
* 5 F1 key press (F above the reference C). VCO frequency with P17
(VCO Scale) to 43.6 Hz einjustieren.
* 6 Steps 4 And 6 Repeat until the frequency values stable.
* 7 Press F5 (F 4 1 / 2 octaves above the reference C). VCO
frequency with P18 (VCO High End trim) to 698.4 Hz einjustieren.
* 8 Steps 4 To 7 Repeat again and possibly nachjustieren.
The VCO offset trimpot P16 is the absolute pitch einjustiert situation
so that middle position of P2 (Tune) and the receipt of the reference
tone (tiefstmöglicher sound) a VCO frequency of about 32 Hz resulted.
32703 Hz in accordance with the pitch of a "C" with MIDI code 24
(decimal). At the customer's request, the VCO also tuned an octave
higher, (65406 Hz = "C", with MIDI code 36). Since the MS-404 probably
bass in the area frequently used, but should be enough reserve to
bottom, and therefore the standard adjustment to MIDI code 24th
---
With these instructions I should be able to tune the MS404 if someone
can tell me which trimmer is which on the circuit board. I have
uploaded a photo of it here:
http://www.rolamtech.com/synths/ms404_board.jpg
Regards,
Giles