Vintage Synth Repair

Heya!

Would anyone have any idea what brand/model the modulation lever 
potentiometers in Oberheim Matrix-12 are? Also, can anyone recommend a 
source for spare parts?

Thanks!
--
.Arto.

Cantos Music Foundation bought the last of the Oberheim Service Departments part stock that former OB service manager Tom Dunn had sold to MT Services a couple of years ago.  

Email LeimseiderJ@... and he may have the part.  



________________________________

From: Arto Koivisto <arto.koivisto@...>
To: vintagesynthrepair@yahoogroups.com
Sent: Monday, October 3, 2011 12:42 AM
Subject: [vintagesynthrepair] Matrix-12 potentiometers


  
Heya!

Would anyone have any idea what brand/model the modulation lever 
potentiometers in Oberheim Matrix-12 are? Also, can anyone recommend a 
source for spare parts?

Thanks!
--
.Arto.

> Cantos Music Foundation bought the last of the Oberheim Service
> Departments part stock that former OB service manager Tom Dunn had sold

Thanks for the tip! As funny as it is, I'm actually stuck at the moment 
trying to locate a proper hex screwdriver to remove the lever / spring 
mechanism from the potentiometer to take a photo & measure dimensions :)

Not sure if its some imperial size, all the metric ones I have (1mm / 
1,5mm / 2mm) are either slightly too big or small. I'll probably try 
some torx precision screwdrivers next, those usually work with hex as well.

Regards,
--
.Arto.

> Not sure if its some imperial size, all the metric ones I have (1mm /
> 1,5mm / 2mm) are either slightly too big or small. I'll probably try
> some torx precision screwdrivers next, those usually work with hex as well.

Just to "wrap up" here, I got this Matrix stuff sorted out last weekend 
(finally!). The way things went, a lot of drilling was involved and I 
ended up enlarging/threading all the set screw inserts for a slightly 
bigger (and most importantly, metric) one. More details here:

http://amazingdiy.wordpress.com/2011/11/18/matrix-12-control-repairs/

Finding a replacement potentiometer was actually rather trivial. I ended 
up using (the relatively standard-sized?) carbon track Weltron/Radiohm 
CIP20C potentiometers like these:

http://www.awatronic.co.uk/carbon-rotary-potentiometers-radiohm-cip20c-mono-/cat_184.html

As the shaft is plastic, trimming it down to proper length is a breeze. 
Installation holes in the lever mech had to be enlarged to 10mm diameter 
for these spares to fit. The shaft is also slightly smaller in diameter 
(I'm guessing 1/4" vs. 6mm -> .35mm difference), but thanks to set 
screws this poses no problem.

Nothing much else to say than what a fantastic and versatile synth! Too 
bad I won't be able to keep it in my music setup for good.. ;)

.Arto.

> Nothing much else to say than what a fantastic and versatile synth! Too

Well, I gotta add that the lever design does have a minor short-coming. 
Since the potentiometer is installed upside down, the contact pin 
opening in the shell is pretty much a 'open welcome' for dust. Not sure 
if there's any (sub panel) dust cover for the levers by design, this 
particular one sure didn't have any.

Come to think of it, maybe I'll add a piece of mylar tape to cover up 
the opening :)

.Arto.

Arto, I usually tape it up and then cover the tape with a smear of silicone sealant!

Cheers,
TOM



--- In vintagesynthrepair@yahoogroups.com, Arto Koivisto <arto.koivisto@...> wrote:

>
> > Nothing much else to say than what a fantastic and versatile synth! Too
> 
> Well, I gotta add that the lever design does have a minor short-coming. 
> Since the potentiometer is installed upside down, the contact pin 
> opening in the shell is pretty much a 'open welcome' for dust. Not sure 
> if there's any (sub panel) dust cover for the levers by design, this 
> particular one sure didn't have any.
> 
> Come to think of it, maybe I'll add a piece of mylar tape to cover up 
> the opening :)
> 
> .Arto.
>