Hi Bob,
I got this sorted in the end by putting new sockets for the filter chips in
and re-flowing all joints. Before, I was losing amplitude at either end of
the cutoff freq across all the voices, now it's all as described in the
resonance calibration section.
Most of the chips were stiff in their sockets, so I don't know if this was
a combination of electrolysis and dry joints or not? I've still got one
voice that takes a little longer to warm up than the others and suspect
it's a related issue.
Patrick
On Wed, Jul 31, 2013 at 4:11 PM, Bob Stewart <bob@blzproductions.com> wrote:
> No, no other issues.
>
> I swapped the filter caps with another channel to if the issue would move
> with the caps, but the issue remained where it was. Short of stripping the
> board, ultrasonicaly cleaning board and rebuilding with new sockets, I was
> kind of at a dead end.
>
> Interested to see if you turn up anything
>
> Cheers
>
> B
>
> On Wednesday, July 31, 2013, murger wrote:
>
> > ∗∗
> >
> >
> > Thanks for that Bob. That all sounds pretty frustrating. Mine is working
> > after a 20 min warm up period or so and I've ruled out the ssm as well.
> >
> > Based on your experience I'll start by sticking a new turnpin socket in,
> > reflow everything and perhaps give it a clean as well then take some
> > freezer spray to the circuit. Will let you know how I get on. Did you
> > change all the ceramics (these can breakdown) and mylars around the
> filter
> > chip then?
> >
> > And have you had any other associated issues with that voice? I have a
> > different voice which is pretty much a semitone flat of all the others,
> > that also takes around 20 mins or so to settle.
> >
> > Pat
> >
> > --- In PolySix@yahoogroups.com <javascript:_e({}, 'cvml',
> > 'PolySix%40yahoogroups.com');>, Bob Stewart <bob@...> wrote:
> > >
> > > Hi Pat.
> > >
> > > No didn't get to the bottom of it, but it wasn't any of the
> following...
> > >
> > > Filter chip, electrolytics, filter caps, control inputs (multiplexers),
> > VCA
> > > transistors (just incas it was a loading issue).
> > > The only thing I did that seemed to make difference was to clean the
> > board
> > > with isopropyl. The effect of doing this was that once the Polysix
> > > has warmed up.... The problem disappears.
> > > I can only think that the issue is related to either spillage, or
> > > electrolyte on the board in that area.
> > >
> > > If you have any joy, please let me know.
> > >
> > > Cheers
> > >
> > >
> > > B
> > >
> > > On Wednesday, July 31, 2013, murger wrote:
> > >
> > > > ∗∗
> > > >
> > > >
> > > > Hi Bob,
> > > >
> > > > Any luck with this one? Got the same issue. Looking at the 560p
> between
> > > > pin 4 and 5 of the ssm.
> > > >
> > > > Pat
> > > >
> > > > --- In PolySix@yahoogroups.com <javascript:_e({}, 'cvml',
> > 'PolySix%40yahoogroups.com');> <javascript:_e({}, 'cvml',
> > > > 'PolySix%40yahoogroups.com');>, Robert Stewart <bob@> wrote:
> > > > >
> > > > > First thing I did.
> > > > > Problem is not the SSM2044
> > > > >
> > > > > :-s
> > > > > On 10/07/2013 14:53, alesisfusion8hd wrote:
> > > > > >
> > > > > > Have you swap SSM2044 with another voice to make sure the issue
> > > > > > follows the filter? Never serviced a Polysix though, but I had a
> > > > > > similar behavior on my Trident MkII. The SSM2044 was faulty.
> > > > > >
> > > > > > HTH
> > > > > > François
> > > > > >
> > > > > > --- In PolySix@yahoogroups.com <javascript:_e({}, 'cvml',
> > 'PolySix%40yahoogroups.com');> <javascript:_e({}, 'cvml',
> > > > 'PolySix%40yahoogroups.com');> <mailto:PolySix%40yahoogroups.com<javascript:_e({},
> 'cvml', 'PolySix%2540yahoogroups.com');><javascript:_e({},
> > 'cvml', 'PolySix%2540yahoogroups.com');>>,
> > > >
> > > > > > "blzproductions" <bob@> wrote:
> > > > > > >
> > > > > > > Hi
> > > > > > >
> > > > > > > Servicing a Polysix for a client, and have come up against a
> > weird
> > > > > > issue, which I can't fathom. Hoping someone out there has had a
> > > > > > similar issue, and may be able to help...
> > > > > > >
> > > > > > > One voice has a faulty filter section in that the resonance can
> > be
> > > > > > adjusted as per the line up procedure, but then if you lower the
> > cut
> > > > > > off, the resonance decreases.
> > > > > > >
> > > > > > > I have ruled out the problem being the SSM2044, all signals
> > coming
> > > > > > into the chip (ie. cut off/resonance control etc.) look correct,
> > and
> > > > > > are comparable, and I'm pretty sure it's not the filter caps as
> > > > > > they're not electrolytics or Tantalums.
> > > > > > > Also the connections between the caps and the filter chip are
> > all OK.
> > > > > > >
> > > > > > > If anyone has any ideas, please get it touch. It's beginning to
> > > > > > drive me mad.
> > > > > > >
> > > > > > >
> > > > > > > Bob
> > > > > > >
> > > > > >
> > > > > >
> > > > >
> > > > >
> > > > >
> > > > > [Non-text portions of this message have been removed]
> > > > >
> > > >
> > > >
> > > >
> > >
> > >
> > > [Non-text portions of this message have been removed]
> > >
> >
> >
> >
>
>
> [Non-text portions of this message have been removed]
>
>
>
> ------------------------------------
>
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