To: 'Analogue Heaven' analogue@hyperreal.org,
From: "Caloroso, Michael E" CalorosoME@corning.com,
cc:
Subject: [AH] Memorymoog+ Repair Day + MIDI Upgrade
Date: Fri, 05 Mar 1999 14:32:59 -0500

---

Cary Robert writes:

> I looked at his memorymoog last summer, and was not able to make it
> any better. I do not believe it is a dirty contact, although it is
> possible. Someone of McNiff's experience should have spotted the problem
> if it were as simple as dirty contacts. I had adjusted the summers for
> the voice CVs and was able to make mono mode track, but then I couldn't
> get it to track in poly mode. There might be a problem in the poly
> or mono glide circuit dumping a low amplitude CV into the voice summers.
> I think that would be the route I would investigate next.
>
Might want to check the S&H circuits, as the caps can fail in these too.
The monophonic signal goes through three or four circuits between the S&H
and the voice cards. Dirty contacts are far more common, but I wouldn't
rule out any circuit problems.

> I'm not sure a memorymoog can handle too many more transcontinental
> shipments.
>
Mine has been gigged around (in a flight case) for ten years and has
survived two four foot drops to the floor, with minor damage like a busted
XLR jack & tuning pot, but still 100% functional. There's been many a night
I've THROWN the MM case in the bus/truck out of frustration yet it didn't
blink. They're tougher than you think.

Then Tom Butcher & Charles Jowett write:

> > Also, Fred McNiff has a firmware upgrade for the MM+
> > that adds additional MIDI functionality (incl. channel
> > select). Has anyone used this? Are there any
> > disadvantages to upgrading?
>
> I'd be interested to hear if this upgrade improves the
> timing of the MM+ MIDI. I've thought about taking the
> factory MIDI out and having a Kenton kit put in, because the
> timing is so sloppy.
>
I bought a DBM Tech Services MIDI upgrade for my MM+ from Fred way back in
1991.

The DBM upgrade removes the omni mode and adds MIDI control of Volume, Pitch
Bend, Modulation Wheel, Sustain Pedal, and footpedal. MIDI channel is
selectable. Minimal, but way better than the factory MIDI implementation.
MIDI Channel select replaces the security code (C-8), but all other
functions are retained. I've never needed a MIDI Channel filter to keep is
from crashing. There are ROM replacements and some wiring involved (less
than the Kenton).

The DBM upgrade is only applicable for MM plusses with the sequencer/MIDI
board.

As far as the sloppy timing issue, I don't know for sure if the DBM upgrade
improves any timing, but I sure don't notice any slop in my unit.

The Kenton kit only interfaces with the keyboard scanning circuitry, so you
still have the original slop problem to deal with.

> The '0' button no longer works on my MemoryMoog. I've got
> the service manual and read up on replacing the switch
> contacts. I have a quick question for the MM+ experts.
> Should I try and replace the spring contacts? Or will
> cleaning be sufficiant? Is it possible to clean the
> contacts without de-soldering the spring contact? Does
> anyone have any experience with this?
>
The button contacts are also tin-plated and will oxidize. Mine started
doing that and just repeatedly pushing down on the button eventually scraped
it clean. On one of the stubborn ones I pushed down REAL hard, and it's
been fine since. You can get between the contacts with a pipe cleaner and
denatured alcohol (WARNING Alcohol is extremely flammable, keep it away from
sources of heat). Don't use rubbing or isopropyl alcohol, these will leave
a film behind. You'll have a lot of fun disassembling the control panel :)

You shouldn't have to replaced the switch contacts unless they are crushed
beyond their original form.

> As today seems to be MemoryMoog repair day...
>
Anybody else? ;)

MC

Opinions (and mistakes) expressed herein are my own and not those of my
employer.