Vintage Synth Repair

Hey there List!
Suddenly my Odyssey MKIII is not working properly. I can hear the normal hiss from the unit 
at normal volume and when I press the keys I can hear that normal low end clicking sound 
but the tones out of the oscillators and noise generator are practically gone.  I can still hear 
the oscillators working at a very very very low volume.  I move all the sliders and try 
everything but still not working like it was.  Since I got the thing I have replaced 
the key bushings and put some deoxit lube in the sliders.  The night before I was running a 
bass guitar through the audio input and messing with the sounds of that (not that cool 
sounding) with the filter.  I powered off the unit, then the next day powered it up and have 
this problem.  I opened it up and everything seems to look fine on the PCB board but I am 
not an expert.  Any thoughts?
Thanks much,
Dylan Nau

It's unlikely that any parts are just going to quit working overnight,
so start with the obvious: make sure everything is turned on properly,
then make sure your connections to all of your equipment are solid and
not flaky.

Open up the Initial Gain slider and see if that changes the volume at all.

If not, then it might be the VCA that's at fault. If it does make some
change (any change), then it might be upstream at the filter.

Get the service manual here (www.arpodyssey.com) and try listening to
the output at the suggested Test Points listed on pages 19-24.  Start
at the VCOs and work south.

Might be dirt in a slider, might be corroded connector strips, might
be no trigger or gate from the keyboard, might be a bad transistor in
the envelope generator(s).  Or something else.

Good luck.

--- In vintagesynthrepair@yahoogroups.com, "nau.dylan" <dylannau@...>
wrote:
>
> Hey there List!
> Suddenly my Odyssey MKIII is not working properly. I can hear the
normal hiss from the unit 
> at normal volume and when I press the keys I can hear that normal
low end clicking sound 
> but the tones out of the oscillators and noise generator are
practically gone.  I can still hear 
> the oscillators working at a very very very low volume.  I move all
the sliders and try 
> everything but still not working like it was.  Since I got the thing
I have replaced 
> the key bushings and put some deoxit lube in the sliders.  The night
before I was running a 
> bass guitar through the audio input and messing with the sounds of
that (not that cool 
> sounding) with the filter.  I powered off the unit, then the next
day powered it up and have 
> this problem.  I opened it up and everything seems to look fine on
the PCB board but I am 

> not an expert.  Any thoughts?
> Thanks much,
> Dylan Nau
>

Thanks alot for the reply.  I finally decided my knowledge is not enough to attempt to find 
the problem here.  When you say "listen" to the test spots, do you mean check voltages? I 
have managed to ruin stuff in the past and I certainly did not want to ruin my ARP because 
it is one of my faves.  I found a local guy who actually came to my house, picked up the 
synth and charges $30/hr starting when he opens up the unit.  Seems like a pretty good 
deal.  He also seemed to think the problem lies somewhere in the filter section as there 
was some change in volume as you raised the VCA gain.  Thanks alot for your reply and 
the help.  Hopefully in the future after i learn some more I can attempt to troubleshoot my 
synths more effectively.  Thanks again.
Dylan Nau

 --- In vintagesynthrepair@yahoogroups.com, "balderson04" <djacklin@...> wrote:

>
> It's unlikely that any parts are just going to quit working overnight,
> so start with the obvious: make sure everything is turned on properly,
> then make sure your connections to all of your equipment are solid and
> not flaky.
> 
> Open up the Initial Gain slider and see if that changes the volume at all.
> 
> If not, then it might be the VCA that's at fault. If it does make some
> change (any change), then it might be upstream at the filter.
> 
> Get the service manual here (www.arpodyssey.com) and try listening to
> the output at the suggested Test Points listed on pages 19-24.  Start
> at the VCOs and work south.
> 
> Might be dirt in a slider, might be corroded connector strips, might
> be no trigger or gate from the keyboard, might be a bad transistor in
> the envelope generator(s).  Or something else.
> 
> Good luck.
> 
> --- In vintagesynthrepair@yahoogroups.com, "nau.dylan" <dylannau@>
> wrote:
> >
> > Hey there List!
> > Suddenly my Odyssey MKIII is not working properly. I can hear the
> normal hiss from the unit 
> > at normal volume and when I press the keys I can hear that normal
> low end clicking sound 
> > but the tones out of the oscillators and noise generator are
> practically gone.  I can still hear 
> > the oscillators working at a very very very low volume.  I move all
> the sliders and try 
> > everything but still not working like it was.  Since I got the thing
> I have replaced 
> > the key bushings and put some deoxit lube in the sliders.  The night
> before I was running a 
> > bass guitar through the audio input and messing with the sounds of
> that (not that cool 
> > sounding) with the filter.  I powered off the unit, then the next
> day powered it up and have 
> > this problem.  I opened it up and everything seems to look fine on
> the PCB board but I am 
> > not an expert.  Any thoughts?
> > Thanks much,
> > Dylan Nau
> >
>

> once I get it running the way it s'posed ta,
> I will make a weeks pay off it ...easy.

In case anyone is interested, I have a work-in-progress page about the 
repairs I did for my whiteface Odyssey.. check it out at:

http://www.kewlers.scene.org/bitchard/diy/Odyssey/odyssey.html

Have started building a breakout box (CV/Gate i/o etc) in order to keep 
the case drilling to bare minimum and maintain most of them reversible. 
If anyone has any suggestions on how to extract the trigger signal for 
the env generator from a incoming gate signal, feel free to send your 
comments, links or schematics. Currently I'm planning on duplicating the 
gate to trig converter found in the later Odyssey models using 
off-the-shelf parts. There could also be a siwtchable trigger in jack 
that'd allow switching between external trigger and gate to trigger circuit.

Suggestions for slider dust covers materials (like the test version 
shown at the page) are also welcome ;)

Ta ta,
.Arto.

>> Suddenly my Odyssey MKIII is not working properly. I can hear the
> normal hiss from the unit
>> at normal volume and when I press the keys I can hear that normal
> low end clicking sound
>> but the tones out of the oscillators and noise generator are
> practically gone.  I can still hear
>> the oscillators working at a very very very low volume.

The most likely candidates are:
- Loose contacts somewhere
- some transistor or lowcost opamp that acts as a amplifier need to be  
changed
- some capacitor has losts its value (or shorted out)

Can you still get VCF feedback with resonance at full?
I had an ARP in once that was "dead", but I could get the filter to  
oscillate, and hence the fault was in the signal chain before the  
filter.
You need the service manual to start checking (following) the signals.

tw.

--- In vintagesynthrepair@yahoogroups.com, Terje Winther <terjewi@...>
wrote:

> The most likely candidates are:
> - Loose contacts somewhere
> - some transistor or lowcost opamp that acts as a amplifier need to be  
> changed
> - some capacitor has losts its value (or shorted out)
> 
> Can you still get VCF feedback with resonance at full?
> I had an ARP in once that was "dead", but I could get the filter to  
> oscillate, and hence the fault was in the signal chain before the  
> filter.
> You need the service manual to start checking (following) the signals.
> 
> tw.
>

I'm wondering if the envelope generators are firing.

Try manually changing the VCF cutoff frequency and see if that changes
the sound heard when the VCA gain is up.  If so, the filter is working
and it may be that the EG's aren't being triggered, which takes you to
the EG's and to whether or not it's simply no gate or no trigger from
the keyboard buss.

ARP filters are sealed units and are not subject to easy component
replacement.

And, when I suggested listening to the Test Points in the manual, I
actually meant listening to them.  Shunt the output of the audio test
points (not the CV signal ones) to the output of the Odyssey and see
where the signal drops away.

Bookmarked!

--- In vintagesynthrepair@yahoogroups.com, Arto Koivisto
<arto.koivisto@...> wrote:
>
> > once I get it running the way it s'posed ta,
> > I will make a weeks pay off it ...easy.
> 
> In case anyone is interested, I have a work-in-progress page about the 
> repairs I did for my whiteface Odyssey.. check it out at:
> 
> http://www.kewlers.scene.org/bitchard/diy/Odyssey/odyssey.html
> 
> Have started building a breakout box (CV/Gate i/o etc) in order to keep 
> the case drilling to bare minimum and maintain most of them reversible. 
> If anyone has any suggestions on how to extract the trigger signal for 
> the env generator from a incoming gate signal, feel free to send your 
> comments, links or schematics. Currently I'm planning on duplicating
the 
> gate to trig converter found in the later Odyssey models using 
> off-the-shelf parts. There could also be a siwtchable trigger in jack 
> that'd allow switching between external trigger and gate to trigger
circuit.

> 
> Suggestions for slider dust covers materials (like the test version 
> shown at the page) are also welcome ;)
> 
> Ta ta,
> .Arto.
>

Hi

I am also working on a Odyssey (mk2) which acts weird.

The first problem is the keyboard, it triggers the envelopes and all that
but no matter what key i press the tone won´t change. The keyboard
is recently cleaned (J-wires, cv and gate bus). Monitoring the CV results
in a read out of 15Volts whatever key is pressed. I have checked the
wiring to the keyboard but everything is allright (CV wire to CV bus and Gate
to Gate bus).

The Octave range sellector worked at first try, but moving it now makes no difference
(same octave whatever the sellector possition is in).

The third problem is OSC 2. First it didn´t make a sound. Now it does but at
LFO range, trimming the OSC 2 retrig pot on the PCB makes the OSC go a little faster
but not up to audio range. attenuating the OSC 2 frequency slider affects the tuning of
OSC 1 a little bit.

This Odyssey has all new (tantalum and electrolytic) caps, sliders, keyboard is cleaned
and has had it´s bushings replaced.

Has anyone on here ever had problems with the interconnection board that connects
all of the frontpanel PCBs together ? Seems like the problems this Odyssey has moves
arround a little. (I mean is the interconnection board known for causing problems ?)

Any suggestions ?

Best regards,

On Wednesday 06 February 2008 08:42, SynthX SynthX wrote:
> This Odyssey has all new (tantalum and electrolytic) caps, sliders,
> keyboard is cleaned and has had it´s bushings replaced.

_New_ sliders?  Do you have a source for these?

-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space,  a critter that can
be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin

On Wednesday 06 February 2008 08:42, SynthX SynthX wrote:
> This Odyssey has all new (tantalum and electrolytic) caps, sliders,
> keyboard is cleaned and has had it\ufffds bushings replaced.

_New_ sliders? Do you have a source for these?

Somebody on ebay is selling remanufactured sliders:

http://stores.ebay.de/Anglian-Art_synthesizer-parts_W0QQfsubZ14


-- 
Malte Rogacki gacki@... 
----------------------------------------------------------------------------
"Don't forget to TURN ON THE SYNTHESIZER. Often this is the reason why you
 get no sound out of it." (ARP 2600 Owner's Manual)
----------------------------------------------------------------------------

On Wednesday 06 February 2008 17:31, Malte Rogacki wrote:
> > On Wednesday 06 February 2008 08:42, SynthX SynthX wrote:
> > > This Odyssey has all new (tantalum and electrolytic) caps, sliders,
> > > keyboard is cleaned and has had it´s bushings replaced.
> >
> > _New_ sliders? Do you have a source for these?
>
> Somebody on ebay is selling remanufactured sliders:
>
> http://stores.ebay.de/Anglian-Art_synthesizer-parts_W0QQfsubZ14

Interesting.  Too bad my german is about useless.  I don't see any easy way to 
translate the page nor does that stuff come up with a search on the US end of 
ebay.  I'll have to keep it in mind,  though,  as I do need *one* slider at 
this point,  for an Omni I have sitting in storage (the 1M "Release" slider).

-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space,  a critter that can
be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin

Interesting. Too bad my german is about useless. I don't see any easy way to
translate the page nor does that stuff come up with a search on the US end of
ebay. I'll have to keep it in mind, though, as I do need *one* slider at
this point, for an Omni I have sitting in storage (the 1M "Release" slider).

Actually the seller is on ebay UK.

And here's the ebay.com URL:

http://stores.ebay.com/Anglian-Art_synthesizer-parts_W0QQfsubZ14

He ships worldwide. Of course buying 10 sliders if you need a single one is
a bit overkill...


-- 
Malte Rogacki gacki@... 
----------------------------------------------------------------------------
"Don't forget to TURN ON THE SYNTHESIZER. Often this is the reason why you
 get no sound out of it." (ARP 2600 Owner's Manual)
----------------------------------------------------------------------------

On Wednesday 06 February 2008 18:40, Malte Rogacki wrote:
> Interesting. Too bad my german is about useless. I don't see any easy way
> to translate the page nor does that stuff come up with a search on the US
> end of ebay. I'll have to keep it in mind, though, as I do need *one*
> slider at this point, for an Omni I have sitting in storage (the 1M
> "Release" slider).
>
> Actually the seller is on ebay UK.
>
> And here's the ebay.com URL:
>
> http://stores.ebay.com/Anglian-Art_synthesizer-parts_W0QQfsubZ14

Thanks,  that one does work much better for me than the other.  :-)

> He ships worldwide. Of course buying 10 sliders if you need a single one is
> a bit overkill...

Indeed.  I'm rather fond of ARP stuff,  and used to work on it quite a bit 
many years ago,  but I sure havnen't run into any lately,  much.  And a bit 
under $6 for a slider is not a bad price at all,  really.

-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space,  a critter that can
be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin

On Thursday 07 February 2008 02:56, SynthX SynthX wrote:
> Hi again,
>
> About the ARP Odyssey sliders, I don´t know if this has been discussed on
> this list before or if it is common knowledge but ...
>
> I have been researching the Odyssey sliders on the net, and found out that
> the original company is very much alive today and still making the sliders,
> or at least they have them in their slider catalogue. However I have been
> unsucessfull in finding a retailer for CTS products.

I've loaded the page,  and on the "potentiometers" page they only show two 
slidepot series neither of which looks like what we're talking about,  but 
I've also downloaded their catalog and will browse it later.

> I´ve searched all the usual one´s mouser, digikey, farnell and so on...
> Seems no one has anything made by CTS in stock.
>
> So I thought if enough people need sliders maybe it would be possible to
> order directly from the CTS company ?
>
> Anyway the company webpage is www.ctscorp.com if you like to check them
> out.

There appears to be a fascinating selection of products there,  and a 
distributor login page,  so perhaps something can be figured out.  Are any of 
the rest of you folks looking for any ARP slidepots?

-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space,  a critter that can
be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin

--- In vintagesynthrepair@yahoogroups.com, SynthX SynthX
<synth_guru@...> wrote:
>
> 
> Hi again,
>  
> About the ARP Odyssey sliders, I don´t know if this has been
discussed on this
> list before or if it is common knowledge but ...
>  
> I have been researching the Odyssey sliders on the net, and found
out that the original
> company is very much alive today and still making the sliders, or at
least they have them
> in their slider catalogue. However I have been unsucessfull in
finding a retailer for CTS products.
>  
> I´ve searched all the usual one´s mouser, digikey, farnell and so
on... Seems no one has
> anything made by CTS in stock.
>  
> So I thought if enough people need sliders maybe it would be
possible to order directly from
> the CTS company ?
>  
> Anyway the company webpage is www.ctscorp.com if you like to check
them out.
>  
> Best regards,
> _________________________________________________________________
> Spara, redigera och organisera dina foton enkelt med Photo Gallery!
> http://get.live.com/photogallery/overview
>
Try this :

http://www.electronicsurplus.com/

On Thursday 07 February 2008 09:19, Scott wrote:
> Try this :
>
> http://www.electronicsurplus.com/

Looks like "a lot of interesting junk",  at least.  :-)

-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space,  a critter that can
be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin

No virus found in this incoming message.
Checked by AVG Free Edition.
Version: 7.5.516 / Virus Database: 269.19.21/1265 - Release Date: 2/7/2008 11:17 AM

No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.5.516 / Virus Database: 269.19.21/1265 - Release Date: 2/7/2008 11:17 AM

The sliders used in the Ody (and a couple other Arps) were made in Mexico.  Once that plant 
was closed, that was it for those sliders.

Shameless plug alert:  I have some 100k Linear ones available, thanks to my better half 
finding them awhile ago. :)

~Monica
http://www.synthfool.com/store

Well, I sent my Arp to a repair guy.  It came back and it worked for about an hour.  I went 
upstairs, came back an hour later and same thing, "extremely low output". Heres what the 
repair guy did.  "repaired caps in audio path around filter, lubed and cleaned 
switches/sliders, reflowed solder connections around ADSR path, cleaned audio 
connectors".  I can hear the filter working, The ADSR is also working as I can hear the 
attack slider working too.  Could it be something in the output section or something? I've 
noticed that the Odyssey has quite a hum/buzz to it even when it is turned off.  The Buzz 
goes away if I take the power cable out but otherwise is still there even when unit is turned 
off.
Also, the lights in my house often drop down suddenly when things like the washer are 
running, could these small surges of power be messing up My Odyssey? Blowing those 
caps around the filter?  
I have all new sliders from that guy in the UK, they seem kinda cheap but hopefully they 
will work for long time. Thanks list!
Dylan Nau
Mpls, MN

> I'm wondering if the envelope generators are firing.
> 
> Try manually changing the VCF cutoff frequency and see if that changes
> the sound heard when the VCA gain is up.  If so, the filter is working
> and it may be that the EG's aren't being triggered, which takes you to
> the EG's and to whether or not it's simply no gate or no trigger from
> the keyboard buss.
> 
> ARP filters are sealed units and are not subject to easy component
> replacement.
> 
> And, when I suggested listening to the Test Points in the manual, I
> actually meant listening to them.  Shunt the output of the audio test
> points (not the CV signal ones) to the output of the Odyssey and see
> where the signal drops away.
>

On Sunday 09 March 2008 19:34, nau.dylan wrote:
> Well, I sent my Arp to a repair guy.  It came back and it worked for about
> an hour.  I went upstairs, came back an hour later and same thing,
> "extremely low output". Heres what the repair guy did.  "repaired caps in
> audio path around filter, lubed and cleaned switches/sliders, reflowed
> solder connections around ADSR path, cleaned audio connectors".  I can hear
> the filter working, The ADSR is also working as I can hear the attack
> slider working too.  Could it be something in the output section or
> something? I've noticed that the Odyssey has quite a hum/buzz to it even
> when it is turned off.  The Buzz goes away if I take the power cable out
> but otherwise is still there even when unit is turned off.

That sounds to me like you might have an issue with either the cable you're 
using to take the output from,  or perhaps the input of the amplifier you're 
driving.  I'd try a different cable first,  see if anything changes...


-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space,  a critter that can
be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin

hmmm, I wish it was that easy. The cord and PA work fine.  

--- In vintagesynthrepair@yahoogroups.com, "Roy J. Tellason" <rtellason@...> wrote:

>
> On Sunday 09 March 2008 19:34, nau.dylan wrote:
> > Well, I sent my Arp to a repair guy.  It came back and it worked for about
> > an hour.  I went upstairs, came back an hour later and same thing,
> > "extremely low output". Heres what the repair guy did.  "repaired caps in
> > audio path around filter, lubed and cleaned switches/sliders, reflowed
> > solder connections around ADSR path, cleaned audio connectors".  I can hear
> > the filter working, The ADSR is also working as I can hear the attack
> > slider working too.  Could it be something in the output section or
> > something? I've noticed that the Odyssey has quite a hum/buzz to it even
> > when it is turned off.  The Buzz goes away if I take the power cable out
> > but otherwise is still there even when unit is turned off.
> 
> That sounds to me like you might have an issue with either the cable you're 
> using to take the output from,  or perhaps the input of the amplifier you're 
> driving.  I'd try a different cable first,  see if anything changes...
> 
> 
> -- 
> Member of the toughest, meanest, deadliest, most unrelenting -- and
> ablest -- form of life in this section of space,  a critter that can
> be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
> -
> Information is more dangerous than cannon to a society ruled by lies. --James 
> M Dakin
>

Things don't buzz when turned off.  The problem has to be downstream
from the Ody.

You've possibly got a ground loop between the Ody and your PA.  Swap
the audio cable with a known working one and see if that improves it.

Also try plugging the Ody into a completely different household
circuit.  If two units with a bad ground are plugged into the same
side of the 3-phase supply, you can get ground hum.

Finally, take the Ody over to a friend's house and plug it in there,
with his audio cable and see if things are different.

--- In vintagesynthrepair@yahoogroups.com, scott frye
<painintheamp@...> wrote:
>
> That all sounds like it's routed in a secondary power supply problem
> They worked then...a whole bunch of stuff didnt work.
> I have a diagram for the thing it that would help.
> 
> Scott in Brrrrrrrrrrrrrrrrrrrrmont
> 
> SynthX SynthX <synth_guru@...> wrote:                                  
>  Hi
>   
>  I am also working on a Odyssey (mk2) which acts weird.
>   
>  The first problem is the keyboard, it triggers the envelopes and
all that
>  but no matter what key i press the tone won´t change. The keyboard
>  is recently cleaned (J-wires, cv and gate bus). Monitoring the CV
results
>  in a read out of 15Volts whatever key is pressed. I have checked the
>  wiring to the keyboard but everything is allright (CV wire to CV
bus and Gate
>  to Gate bus).
>   
>  The Octave range sellector worked at first try, but moving it now
makes no difference
>  (same octave whatever the sellector possition is in).
>   
>  The third problem is OSC 2. First it didn´t make a sound. Now it
does but at
>  LFO range, trimming the OSC 2 retrig pot on the PCB makes the OSC
go a little faster
>  but not up to audio range. attenuating the OSC 2 frequency slider
affects the tuning of
>  OSC 1 a little bit.
>   
>  This Odyssey has all new (tantalum and electrolytic) caps, sliders,
keyboard is cleaned 
>  and has had it´s bushings replaced.
>   
>  Has anyone on here ever had problems with the interconnection board
that connects
>  all of the frontpanel PCBs together ? Seems like the problems this
Odyssey has moves
>  arround a little. (I mean is the interconnection board known for
causing problems ?)
>   
>  Any suggestions ?
>   
>  Best regards,      
> 
> 
> ---------------------------------
> Du har väl läst dagens Nemi? MSN Serier 
>      
>                                
> 
> 
>   Scott  Frye
> AudioFixation
> Consumer / Pro Audio Repair
> Southern VT 
> 
>   
> 
> 
> 
>        
> ---------------------------------
> Be a better friend, newshound, and know-it-all with Yahoo! Mobile. 
Try it now.
>
Ive been working on my Odyssey Mk2 in my spare time, and after a good
cleaning (I washed the boards in the sink with soap and water)I put it
back together and did not have pitch control with my keyboard.If you
look at a schematic you will see 5 wires from the keyboard to the
synth; mine had only 4,the orange was not connected. I should note the
keyboard was not mounted in the synth at this time. After some head
scratchin( im not an electronics tech) i connected a wire from the
orange wire on the keyboard to the chassis and what do ya know, It
Worked!! The moral here is that the keyboard and synth make a ground
connection when bolted together. This might help. Paul

You probably all know this, but it puzzled me today working on an early 
minimoog with the metal front panel:
How do you change those rocker switches?
They screws that holds them in place seems to be from the front 
underneath the metal front panel. There is no way you can change them 
from the rear.
So how do people change these? Or du you just clean and re-lubricate 
the switches?


Terje Winther
terje.winther@...
http://www.wintherstormer.no/

> They screws that holds them in place seems to be from the front 
> underneath the metal front panel. There is no way you can change them 
> from the rear.
> So how do people change these? Or du you just clean and re-lubricate 
> the switches?


Hi, can you see any nuts whitch hold the switches?? Or are the threads in the metal chassis of 
the switches? If you see nuts, try to loosen them - maybe that it works. If not you have to 
disassemble the front panel - that means you have to loosen all pots. That´s a bad job - i 
lubricated my switches because i am very lazy. That worked well. So if you dont have any 
cracked switches let them on their place and try to lubricate them. I took DeoxIT Fader Lube, 
formerly MCL, that works fine. 
Greetz
Martin

>  Hi, can you see any nuts whitch hold the switches??

No, unfortunately not.

>  Or are the threads in the metal chassis of  the switches?

Yes, indeed so.

> ... you have to disassemble the front panel - that means you have to 
> loosen all pots. That´s a bad job

I will try to no do that, because it is not broken, just slightly 
intermittent.

>  lubricated my switches because i am very lazy. That worked well. So 
> if you dont have any
>  cracked switches let them on their place and try to lubricate them. I 
> took DeoxIT Fader Lube,
>  formerly MCL, that works fine.

Thanks. I think I will do that and see how it works.


tw.  :)

"Those great moments come when musicians are playing together..."
(Bob Moog)

Hi all,
I am servicing an Oberheim OB-8, and the multiplexers (to the left) on 
the two voice cards get uncomfortably warm after a while.
I just wanted to check with others if this is normal.


Terje Winther
terje.winther@...
http://www.wintherstormer.no/

To: vintagesynthrepair@yahoogroups.com
From: terje.winther@...
Date: Tue, 23 Jun 2009 19:47:02 +0200
Subject: [vintagesynthrepair] polymoog maintenance kit



Years ago, there used to be a "polymoog maintenance kit".