Hi,
I’ve downloaded 3 different manuals for the minimoog but all differ on how to tune the oscillators, and and all have different back panels than mine, and I’ve made a total mess of the tuning now.
Does anyone know where to find a guide on how to tune this particular model?
there are 4 columns: Hi End Scale Octave Shift, whereas the manuals I have have only 2 columns HI and LO, and a SCALE hole.
On mine the hole below the “scale” column has no trimpot
The hole far left is for tuning the 440Hz, and 2 of the label-less on the left of the MOOG logo are for FILTER PITCH and THRESHOLD to set the filter, but what is the other one ?
thanks !
I had done a search on the forum before posting first but ended up with tens of pages that didn’t relate to the minimoog, but on google I found some topics on this forum that explains how to tune it.
Obviously my oscillator board is a “new” one although it was sold to me as the “old” one…
NOTE: I have a new OSC board.
I’ve decided to set everything up as it should before installing the deadband modification on the pitch bend.
So I unplugged the left hand controler and set the center of the pitch bend to 15.3KHz as indicated in the minimoog manual.
When everything plugged back in the pitch had dropped down to 3 semitones compared to how it was set before.
I proceeded to retune the oscillators but the 3rd OSC doesn’t go hi enough, the SHIFT trimpot is at the minimum but the 55Hz I should get at range 16" on the low A is not reachable.
any idea ?
Furthermore, Rudi told me I should have 4.3V between ground and wiper on the pitch bend pot at detent position, but I get 5.3V (PBend is set to 15.3KHz). If I set it to 4.3V I’m down 4 semitones more, that’s 7 semitones lower than the position it was in originally (and I was getting 6.6V), and the oscillators can’t be tuned that much higher
From the photo of the back of your Mini, and since your model has a serial number below 10175, the new oscillator board that you have now has replaced the original “old” oscillator board that came with your Mini from the factory. Just make sure that resistor R59 (located directly on the octave range switch for OSC 1) has been removed (or one of its wires has been cut), as per mentioned on the Minimoog schematics showing the wiring of the front panel when a new oscillator board is installed.
ha here’s a nice clue, thanks Alain! I’m opening the beast right now to see.
After going through lists of components on Kevin’s service manual, I see R59 is listed as a 39kOhm resistor.
(on which document do you find where R59 is ?)
On my OSC 1 range selector there’s a 24kOhm, is that the one ?
and what will happen once removed ?
I noticed on the OSC board a resistor between wiper of the OSC3 SHIFT trimpot and pin 6 of the CTS 8002.
Any idea what it’s for ? could it be why I can’t tune OSC 3 high enough?
Again, sorry that I can’t help you much with that, since I don’t know anything about the new oscillator boards other than what is written in the service manual about it. The 90.9 Ohms resistor should have been removed , according to that manual, when the new osc board was installed in replacement of the original one. But clearly, someone left it in and added another resistor in parallel (to change the resulting resistance value).
And another resistor seems to have been added to the shift trimpot also.
Maybe someone with knowledge about this could maybe shed some light on these mods ?
Alain.
OK Alain thanks, still some precious infos there!
I’ll wait to see if someone familiar with new boards replacing old ones has any advice
All resistors should be 1% tolerance on the octave selectors.
100ppm are ok. 50ppm, better.
The four resistors on the top (starting at the left) are 1K matched resistors.
The fifth resistor is 4.75K resistor and the one resistor that goes across the whole switch is a 90.9ohm resistor.
(note that this is a 90.9ohm, not a 90.9K resistor.)
I may have posted this chart below before.
I may have included an error or two by accident.
But it covers every permutation I’ve seen, up, down, left or right.
(Never assume docs from a manufacturer are always error free anyway.)
Changes regarding range switches.
1st edition: 10 ohm resistors, no current loop resistor, no buffer board, old VCOs
2nd edition: 1K ohm resistors, 90.9 ohm current loop resistor, no buffer board, old VCOs
3rd edition: 1K ohm resistors, 90.9 ohm current loop resistor, buffer board, old VCOs
4th edition: 1K ohm resistors, no current loop resistor, buffer board, new VCOs
Thanks for these infos Kevin!
So I can safely remove the 90.9 ohm and the 24KOhm resitors, what will it affect?
“So I can safely remove the 90.9 ohm and the 24KOhm resistors, what will it affect?”
You can safely remove about 99% of a Minimoog’s part.
As to what it will affect… like you said: tuning.
But… heh… at around 10-20% parts removed, that Mini would probably be silent anyway.
I’m guessing that someone attempted to mod their Mini and could not locate a certain resistor.
But 90.9 ohms with a 24K resistor across it is only 90.557015 ohms (and certainly not 50PPM.)
Whomever that tech was, didn’t quite understand the concept.
I hope you or others are not offended by by my next statement:
I think you should hire a professional and experienced Minimoog tech.
Someone that knows what to do and why.
This photo above is a great representation of what happens when one hires a tech that knows just enough electronics to fix some problems, but not enough to actually understand and solve the original problem.
Thanks,
Kevin
PS: If you fancy yourself a good synth tech and don’t know why I just said this above is poor technique or theory, I’ll gladly explain myself.
Bottom-line: send or take your Mini to a good Moog specialist.
If you use techs that do work as shown in that pic, you might as well just donate your money instead.
Hello Kevin,
I understand what you’re saying.
There are 2 major problems for me:
- there are no specialist around where I live (in france in a small town) (hence the use of this forum…)
- I’ve bought this minimoog from someone who claims he’s a specialist : cem3374.com
He had bad things to say about the main users of this forum when I told him I found out the OSC board had been changed thanks to you guys’s help.
I paid for this synth early Feb but received it late May with tons of BS from him in between. I’m a professional musician and had an album on stand by for 4 months because of this. Now I have the minimoog, I’m recording a lot with it, I can’t afford to send it away for another month at least (and to who ?), particularly if it’s only a matter of removing 2 resistors.
I asked: is it safe to remove this?
you said yes, thanks Kevin!
what will affect?
you said tuning, thanks Kevin!
I simply want to have the deadband mod working and the minimoog in tune. For this I needed the infos you guys have provided, cheers.
chris
I’ve removed the 2 resistors, didn’t hear any difference BUT after re-installing the deadband mod, it is now working as it should !! 
thanks everyone for your help!
Bravo ! Finalement toute cette persévérance aura été bénéfique ! Maintenant, profites-en bien !
Alain.
(for the non french speaking: Congrats ! Finally all your perseverance will have been beneficial ! Now, go enjoy it !)
absolument! merci Alain, you went Dr House on this one! 
Sounds like you fixed it yourself. Congratulations!
It might have just been a bad connection and you cured it.
As for that French site that doesn’t like us here and calls themselves experts.
They probably don’t like me personally because I’ve corrected them on some of their (mis)information:
I had visited their site, saw many things that were factually and provably wrong and told them so.
Well, no one likes to be corrected, especially when they’ve called themselves a “lord” or expert.
True experts rarely call themselves experts.
For example, I call myself a synthfool, not a synth lord.
It’s when others call you an expert that it might be true.
It also doesn’t hurt if those calling a person an expert exist in great numbers, are pro musicians or engineers themselves.
I suggest anyone that calls themselves an expert, go watch an episode of the original Twilight Zone called “A game of pool.”
http://en.wikipedia.org/wiki/A_Game_of_Pool_(1961)
It starred the late Jonathan Winters and Jack Klugman.
This film might change one’s perspective on being… or not being… an expert.
Good viewing suggestion Kevin. Found it easily on YT.
People who call themselves experts are certainly no experts in humility…
There’s a saying that it takes 10 000 hours to be a master at something. I guess I can consider myself an expert at living then… 
Totally agree with you Kevin.
I have to pinpoint that he calls himself a specialist not an expert though, but he still pats himself in the back way too much considering he pretended he had totally dismounted the minimoog he sold me, but hadn’t noticed the osc board had been changed, he didn’t know what the deadband mod was, when you guys recognized the diode loop straight away.
I told him he was bound to have noticed the new board but he swore that he hadn’t.
So that leaves 2 options, he lied about having opened it and didn’t check anything like he’d told me he had, (something that was part of the service I paid for) or he did and lied about the OSC board. In both cases he lost my trust, which had been tested during 4 months when I really thought I’d been conned.
(I can’t even consider he opened it and didn’t notice, that would be insulting )
Sounds like you fixed it yourself. Congratulations!
It might have just been a bad connection and you cured it.
well thanks to you guys!
there’s some weird behaviour on OSC3 though like I mentionned. OSC3 Frequency pot on the front going from almost -11 to almost +5.
(Alain: I’ve removed the resistor on the SHIFT trimpot of OSC3, I just had to tune the SHIFT, the rest (SCALE, HI END) wasn’t affected)
2 questions:
Is that something that can be changed ?
does it matter ?