Vintage Synth Repair

Hi guys, finally decided to work on my Arp Omni 2...wow this thing had 
so many faults I dont where to start...actually I give you a write up 
later! Basically it was a dead pile of boards. Nothing worked.

But anyway now I've got a few faults left I could use help with, I dont 
have original schems and the PDF's on line are terrible, so If anyone 
has a better copy let me know!

Faults:

1: Strings slow attack setting only works on the first note or chord 
pressed, you have to wait for all the notes to have died out before it 
works again, other wise you just get fast attack.

2: 8' Bass and Cello are much quieter than 16' bass and String bass.

3: In the synth section if you set a short release and play one note 
and let go of the key the release is perfect, however if you play more 
notes after that you hear the tail of the previous notes in the current 
note played..if that makes sense?

Basically it sounds just like youve got a long release set all the 
while you're hitting notes.

4: there is no top E to top C 4' sound produce from either the strings 
or the synth section. It is kind of there but very faint.

Thanks, Phil.

Spoke too soon..fault 5 to add to the list:

5: According to the manual hitting the chorus phaser button should 1: 
slow down the phaser modulation speed. Yep it does that! 2: add the 
phaser effect to the Synth section. nope doesnt do that..works fine 
on the strings though.

So I have no phaser on the synth section..


--- In vintagesynthrepair@yahoogroups.com, "eggwheatis" 
<eggwheatis@...> wrote:
>
> Hi guys, finally decided to work on my Arp Omni 2...wow this thing 
had 
> so many faults I dont where to start...actually I give you a write 
up 
> later! Basically it was a dead pile of boards. Nothing worked.
> 
> But anyway now I've got a few faults left I could use help with, I 
dont 
> have original schems and the PDF's on line are terrible, so If 
anyone 
> has a better copy let me know!
> 
> Faults:
> 
> 1: Strings slow attack setting only works on the first note or 
chord 
> pressed, you have to wait for all the notes to have died out before 
it 
> works again, other wise you just get fast attack.
> 
> 2: 8' Bass and Cello are much quieter than 16' bass and String bass.
> 
> 3: In the synth section if you set a short release and play one 
note 
> and let go of the key the release is perfect, however if you play 
more 
> notes after that you hear the tail of the previous notes in the 
current 
> note played..if that makes sense?
> 
> Basically it sounds just like youve got a long release set all the 
> while you're hitting notes.
> 
> 4: there is no top E to top C 4' sound produce from either the 
strings 

> or the synth section. It is kind of there but very faint.
> 
> Thanks, Phil.
>

No 5: fixed..it was just a setting. Doh... you have to have to have 
the mix slider over to the strings side to hear the phaser on the 
synth section...stupid old weird keyboard!

Ok, on with the rest...feel free to chip in!

--- In vintagesynthrepair@yahoogroups.com, "eggwheatis" 
<eggwheatis@...> wrote:
>
> Spoke too soon..fault 5 to add to the list:
> 
> 5: According to the manual hitting the chorus phaser button should 
1: 
> slow down the phaser modulation speed. Yep it does that! 2: add the 
> phaser effect to the Synth section. nope doesnt do that..works fine 
> on the strings though.
> 
> So I have no phaser on the synth section..
> 
> 
> --- In vintagesynthrepair@yahoogroups.com, "eggwheatis" 
> <eggwheatis@> wrote:
> >
> > Hi guys, finally decided to work on my Arp Omni 2...wow this 
thing 
> had 
> > so many faults I dont where to start...actually I give you a 
write 
> up 
> > later! Basically it was a dead pile of boards. Nothing worked.
> > 
> > But anyway now I've got a few faults left I could use help with, 
I 
> dont 
> > have original schems and the PDF's on line are terrible, so If 
> anyone 
> > has a better copy let me know!
> > 
> > Faults:
> > 
> > 1: Strings slow attack setting only works on the first note or 
> chord 
> > pressed, you have to wait for all the notes to have died out 
before 
> it 
> > works again, other wise you just get fast attack.
> > 
> > 2: 8' Bass and Cello are much quieter than 16' bass and String 
bass.
> > 
> > 3: In the synth section if you set a short release and play one 
> note 
> > and let go of the key the release is perfect, however if you play 
> more 
> > notes after that you hear the tail of the previous notes in the 
> current 
> > note played..if that makes sense?
> > 
> > Basically it sounds just like youve got a long release set all 
the 

> > while you're hitting notes.
> > 
> > 4: there is no top E to top C 4' sound produce from either the 
> strings 
> > or the synth section. It is kind of there but very faint.
> > 
> > Thanks, Phil.
> >
>

Update: Fault no3 fixed...was an open transistor Q22 on the lower 
voice board. It's in the 8' Bass wave shaper circuit. 

3 faults to go!

One thing ive discovered pouring over these terrible quality PDF's is 
that the Omni and the Omni 2 have a fairly fundamental difference I 
don't see mentioned on the net anywhere.. The omni has the Bass synth 
8' and 16' sounds routed through the 4075 filter same as the the main 
synth section.

The omni 2 bass has it's very own seperate filter and a more complex 
envelope generator that both reside on the Omni 2 unique 'Bass Voice' 
board. They are both fixed sadly.

This totally changes the sound between the two. I can see why they 
did it but the bass sounded great running through the 4075 filter. I 
miss that. But I suppose it makes it more flexible in the long run.

What they should have done was put in another fully adjustable 4075 
just for bass...that would have been awesome...hmm future mod maybe?

Phil.



--- In vintagesynthrepair@yahoogroups.com, "eggwheatis" 
<eggwheatis@...> wrote:
>
> Hi guys, finally decided to work on my Arp Omni 2...wow this thing 
had 
> so many faults I dont where to start...actually I give you a write 
up 
> later! Basically it was a dead pile of boards. Nothing worked.
> 
> But anyway now I've got a few faults left I could use help with, I 
dont 
> have original schems and the PDF's on line are terrible, so If 
anyone 
> has a better copy let me know!
> 
> Faults:
> 
> 1: Strings slow attack setting only works on the first note or 
chord 
> pressed, you have to wait for all the notes to have died out before 
it 
> works again, other wise you just get fast attack.
> 
> 2: 8' Bass and Cello are much quieter than 16' bass and String bass.
> 
> 3: In the synth section if you set a short release and play one 
note 
> and let go of the key the release is perfect, however if you play 
more 
> notes after that you hear the tail of the previous notes in the 
current 
> note played..if that makes sense?
> 
> Basically it sounds just like youve got a long release set all the 
> while you're hitting notes.
> 
> 4: there is no top E to top C 4' sound produce from either the 
strings 

> or the synth section. It is kind of there but very faint.
> 
> Thanks, Phil.
>

On Sunday 10 August 2008 16:45, eggwheatis wrote:
> ...stupid old weird keyboard!

Hey,  if you decide that you really don't want it,  feel free to send it to 
me...    :-)

-- 
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

I love it, sounds gorgeous...:o) and all fixed now...had a massive 
amount of faults..50% caused by the person who was in there before me!

Phil.

--- In vintagesynthrepair@yahoogroups.com, "Roy J. Tellason" 
<rtellason@...> wrote:
>
> On Sunday 10 August 2008 16:45, eggwheatis wrote:
> > ...stupid old weird keyboard!
> 
> Hey,  if you decide that you really don't want it,  feel free to 
send it to 
> me...    :-)
> 
> -- 
> 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 Monday 25 August 2008 18:17, eggwheatis wrote:
> I love it, sounds gorgeous...:o) and all fixed now...had a massive
> amount of faults..50% caused by the person who was in there before me!
>
> Phil.

Ah well,  I'll run across one that I can snag one of these days...    :-)

> --- In vintagesynthrepair@yahoogroups.com, "Roy J. Tellason"
> <rtellason@...> wrote:
> > On Sunday 10 August 2008 16:45, eggwheatis wrote:
> > > ...stupid old weird keyboard!
> >
> > Hey,  if you decide that you really don't want it,  feel free to
> > send it to me...    :-)

-- 
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