I picked up a Rogue…free. from a co-workers garage. he thought of it as a weird noise making gadget from his band days back in the 80’s. free. but i understand why,as the oscillators must be so out of whack that it just sounds like noise. i have no experience with moog or analog synths of this vintage (i have a roland jx8p), so what i’m looking for is some resources on how to get the rogue tuned. i’ve found scant info online. there are 8 or 9 trimpots accesible by a tiny screwdriver on the back the rogue, i’ve experimented with all trying to get the rogue in tune and sounding ‘musical’ but its still buzzing and hissing at me. the oscillators sound really drifty, buzzy, and the scale and tune are way off. is this serviceable? any ideas where to start?
I have the procedure from the Moog Taurus II Maintenance manual. Taurus II has the same synth engine as the Rogue, but the pedalboard has only 18 notes from C to F. The Rogue has more keys than that, so I am guessing you have to use only the middle 18 notes on the Rogue keyboard for this procedure to work. Thus when it says “press low C” and “press hi C”, the notes are only 1 octave apart.
If looking at the back of the unit (so you can read the Moog logo), the trimpots are as follows from left to right: VCA R139, OSC2 hi R72, OSC1 hi R97, RNG2 R51, SCL2 R48, SCL1 R54, RNG1 R58, OCT R155, KBD SCL R24. Note: just for visual reference, the RNG and SCL trims are all close to each other.
Procedure: Keyboard Scale
Set GLIDE to minimum, use volt meter to monitor voltage at output at tip of KEYBOARD IN/OUT jack. Alternately depress high F and low C keys, and adjust KBD SCL R24 for a 1.41 volt difference between them. This gives you a 1 v/octave scale.
Procedure: OSC1 Scale, Freq, Hi/Low
Set Master Volume and OSC1 Level to max, OSC 2 to min, filter cutoff to max, emphasis to min, filter contour to min, bypass VCA, OCS octave 32’, wave SAW, tuning knob centered, pitch wheel centered.
Center trimpots R58, R54, R97
Monitor audio output jack (i.e., plug it in so you can hear it) and have a tuner handy.
Press & hold low C. Use R58 to tune to 32 Hz.
Press high C, tune to 65 Hz with R54.
Repeat steps until both ends balanced.
Set OCTAVE to 8’.
Press & hold low C, adjust trim R155 for 65 Hz.
Press high C, adjust R97 for 130 Hz.
Repeat until both balance at the correct frequencies (pitches), then re-check lower freq trims and keep setting them until all are stabilized.
Do the same things for OSC2 substituting the OSC2 trim pots as listed earlier.
The first thing to do is open it up. You will find a black foam material, but due to age when you actually touch the foam it turns to goo. Nasty black goo. It must be carefully removed. If you find any goo has gone into the sliders there are new ones available from Technology Transplant (I used this myself when the goo got in some sliders). Seeing as you got it for free this cost is minimal.
The service manual is easily found online. There you can follow the procedure for keyboard scaling, VCA trim and Oscillator scaling - all very easily done from the rear panel.
Here’s one place with the service manual:
All the pdfs I have seen use the same scan, which is in the wrong order. To avoid confusion pdf pages 4 and 5 need to be swapped (i.e. read page 5 first).