Alright, thanks! I'll get me some cooling spray, then get to work.
Peter
--- In
PolySix@yahoogroups.com, Johannes Hausensteiner
<jo.synth@c...> wrote:
> I would not start to replace all components; I would rather try
> to find out the faulty one. Heat up the whole area of the PCB
> using a hot fan. Then you can selectively cool down single
> components with cooling spray. If you start the Arpeggiator
> before you can let play the Polysix for its own and hear changes
> immediately.
>
> Johannes
>
>
> Peter Andersson wrote:
> > You're right, searching for "2SC1583" does give me a bunch of
> > interesting matches. No seller in Sweden but there are shops in
> > Germany, for example, selling both that and the 2SA733. I'll ask
a
> > friend to get them and post them to me. Like you say, the opto
> > resistor (PC-1) could be tough to get hold of, though. I'll
start by
> > replacing the transistors anyway and see if that does anything.
Oh,
> > and what about those amplifier ICs? Is that a long shot you
think?
> >
> > Peter
> >
> > --- In PolySix@yahoogroups.com, Johannes Hausensteiner
> > <jo.synth@c...> wrote:
> >
> >>I read from the schematic:
> >>∗ Q12 is a dual npn transistor, common emitter.
> >> The used type is 2SC1583.
> >> I found a company Dönberg Electronics, who does sell this
> >> component, by entering "2sc1583" into Google
> >>
> >>∗ Q3 is a standard (Japanese) pnp small signal transistor,
> >> type 2SA733. Dönberg also do have this one or you can take
> >> a BC557 as a substitute. But be careful, the pinout is
> >> different:
> >> 2SA733 BC557
> >> B-C-E E-B-C
> >>
> >>∗ PC-1 seems to be a Korg custom component. Doesnt it have a
> >> black rubber tube on it? It is drawn in the schematics as
> >> an LED optically coupled to an LDR. Hm.
> >> Maybe someone of the list has a spare?
> >>
> >>Johannes
> >>
> >>
> >>
> >>Peter Andersson wrote:
> >>
> >>>Wow, that's very useful info! Thanks Johannes!
> >>>
> >>>The control voltage must be crucial for the expo conversion to
> >
> > work
> >
> >>>properly then. If any of the amplifier circuits would be broken
> >>>(IC17, 18 or 19), could that cause this behaviour do you think,
> >
> > or
> >
> >>>would that just make everything fail "from start"?
> >>>
> >>>Well, speaking of which... The synth no longer tunes up
> >
> > correctly
> >
> >>>after 20 minutes. Now the tuning and the note intervals are
> >
> > screwed
> >
> >>>up period. So whatever needed "warming up" a few days ago seems
> >
> > to
> >
> >>>have failed permanently now.
> >>>
> >>>I just went over the soldering points around the components you
> >>>pointed out and resoldered most of them to be sure. I still get
> >
> > the
> >
> >>>same problem, though, so I guess it's time to start replacing
> >>>components. I'll definitely try testing with cooling spray.
Good
> >>>suggestion!
> >>>
> >>>BTW, it seems I can replace all components in the expo
> >
> > conversion
> >
> >>>circuitry easily except Q12, Q3 and PC-1. Can't seem to find
> >
> > info on
> >
> >>>these anywhere. You wouldn't happen to know of components
> >
> > compatible
> >
> >>>to any of these three, would you?
> >>>
> >>>Peter
> >>>
> >>>
> >>>--- In PolySix@yahoogroups.com, Johannes Hausensteiner
> >>><jo.synth@c...> wrote:
> >>>
> >>>
> >>>>The hold capacitors are C56 in unit0..5. But I do not think
that
> >
> > it
> >
> >>>>is the hold capacitors very likey. If it were, not all six
voices
> >>>>would be affected equally. No, it must be something common. If
it
> >>>>is not the wires to/from KLM-396, then the "expo converter" is
my
> >>>>no.1 candidate. KLM-396 seems to be a part of it. The KBD works
> >>>>logarithmically; that is going up a certain number of keys
(e.g.
> >>>>12 for one octave) multiplies the frequency of the generated
note
> >>>>by a certain factor (times 2 in case of an octave). So the KBD
CV
> >>>>logarithmic by its nature, whereas the oscillators work linear;
> >>>>that is, the generated frequency changes linearly with the
> >
> > control
> >
> >>>>voltage (e.g 1V gives 1000Hz, 2V give 2000Hz, 3V give 3000Hz,
> >>>
> >>>etc.).
> >>>
> >>>
> >>>>These two schemes are not compatible to each other but it is
> >>>
> >>>possible
> >>>
> >>>
> >>>>(and necessary) to convert from one to the other. When
converting
> >>>
> >>>>from logarithmic to linear you have to do the opposite of
> >
> > logarithm
> >
> >>>>which is exponential function. It happens that diodes and
> >>>
> >>>transistors
> >>>
> >>>
> >>>>have exponential transfer curves, so they can be used for this
> >>>>purpose. But the exponential function is extrem sensitive to
> >
> > small
> >
> >>>>variations; a small variation of the input causes a big change
at
> >>>>the output. Furthermore the human ear is very sensitive to
> >
> > changes
> >
> >>>>in pitch. This means that there must be taken special measures
> >
> > that
> >
> >>>>the whole thing does not run out of tune.
> >>>>The expo converter in the Polysix is made of IC17, 18, and 19,
> >
> > Q12
> >
> >>>>(the expo component), PC-1 (kind of an opto-coupling device),
Q3,
> >>>>and surrounding components. In case of "old production" units
> >>>>KLM-396 belong to this circuitry, too. Polysix has 6 voices but
> >>>>the analog (de)multiplexers for the CV have 8 inputs/outputs.
The
> >>>>additional 2 inputs/outputs are used for some kind of
calibrating
> >>>>the exp. amplifier and thus stabilizing tuning of the
instrument.
> >>>>I am not 100% sure how this works as the CPU never measures any
> >>>>value and therefore cannot adjust to changing values. From
what I
> >>>>can see from the code there is always the value 0 ouput
> >
> > to "voices"
> >
> >>>>6 and 7.
> >>>>
> >>>>According to what you tell, it may be a thermal problem. So I
> >
> > would
> >
> >>>>carefully check all solder points and try to heat up / cool
down
> >>>>the PCB in the area where these components are located. With
> >>>
> >>>cooling
> >>>
> >>>
> >>>>spray you may identify a faulty component.
> >>>>
> >>>>Johannes
> >>>>
> >>>>
> >>>>Peter Andersson wrote:
> >>>>
> >>>>
> >>>>>Yes, it's an old production unit alright. I've checked the
> >
> > wires
> >
> >>>>>between the 366 and the 396. It seems ok, the solder joints
too.
> >>>>>
> >>>>>Can you tell me which major components are actually involved
in
> >>>
> >>>the
> >>>
> >>>
> >>>>>lin/log conversion/tuning? I've been told to "check" the key
> >>>
> >>>voltage
> >>>
> >>>
> >>>>>selector chip, the DAC and the S/H capacitors as well as
> >>>
> >>>something
> >>>
> >>>
> >>>>>called an expo converter. (I don't understand half of this
> >
> > stuff
> >
> >>>to
> >>>
> >>>
> >>>>>be honest - I know you're not surprised. I'm learning,
> >
> > though...
> >
> >>>>>quickly!). These are some of the key components of the 366 as
> >>>
> >>>far as
> >>>
> >>>
> >>>>>I understand. Do they handle the conversion/tuning you're
> >>>
> >>>refering
> >>>
> >>>
> >>>>>to? I thought I'd start out by replacing the S/H capacitors.
> >
> > The
> >
> >>>>>cheapest and easiest operation to start with, I thought.
> >>>
> >>>However, I
> >>>
> >>>
> >>>>>haven't even been able to locate them. It's nearly impossibe
to
> >>>
> >>>read
> >>>
> >>>
> >>>>>the numbers on the 366 schematics I got off the Old Crow web
> >>>
> >>>site.
> >>>
> >>>
> >>>>>(Man what a fantastic resource his site is, btw!).
> >>>>>
> >>>>>Again, thanks for helping!
> >>>>>
> >>>>>--- In PolySix@yahoogroups.com, Johannes Hausensteiner
> >>>>><jo.synth@c...> wrote:
> >>>>>
> >>>>>
> >>>>>>From what you tell I would say it is a problem on the KLM-
366,
> >>>
> >>>in
> >>>
> >>>
> >>>>>>the log/lin conversion/tuning section.
> >>>>>>Or maybe you have one of the rare "old production" units. Is
> >>>
> >>>there
> >>>
> >>>
> >>>>>>a small add-on board "KLM-396" to the KLM-366?
> >>>>>>It could be a lose wire (if "old production") and/or a bad
> >
> > solder
> >
> >>>>>>joint.
> >>>>>>I can see that you are located in Sweden; maybe you ask
Ricard
> >>>>>>( http://home.swipnet.se/ricard2/p6index.html ) for
technical
> >>>
> >>>help.
> >>>
> >>>
> >>>>>>Peter Andersson wrote:
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>>Actually, tones are quite stable even during the first 20
> >>>>>
> >>>>>minutes, but
> >>>>>
> >>>>>
> >>>>>
> >>>>>>>the synth is not in tune generally. Also, an octave is a
> >
> > quite
> >
> >>>>>stable
> >>>>>
> >>>>>
> >>>>>
> >>>>>>>major 7 interval for the first 20 minutes, until suddenly,
> >
> > the
> >
> >>>>>synth
> >>>>>
> >>>>>
> >>>>>
> >>>>>>>goes into tune and then the octave is correct as well. I'll
> >>>
> >>>check
> >>>
> >>>
> >>>>>>>tonight if a single generated tone changes a lot during the
> >>>>>
> >>>>>first 10
> >>>>>
> >>>>>
> >>>>>
> >>>>>>>sec.
> >>>>>>>
> >>>>>>>All six voices are affected. If I play a chord when it
> >
> > suddenly
> >
> >>>>>slides
> >>>>>
> >>>>>
> >>>>>
> >>>>>>>out of pitch, all notes follow. It actually sounds like I'm
> >>>>>
> >>>>>turning
> >>>>>
> >>>>>
> >>>>>
> >>>>>>>the pitch wheel. (I disconnected the pitch wheel, btw, just
> >
> > to
> >
> >>>>>be sure
> >>>>>
> >>>>>
> >>>>>
> >>>>>>>it wasn't playing tricks on me).
> >>>>>>>
> >>>>>>>It is not related to the MG setting and I've played around
> >
> > with
> >
> >>>>>all
> >>>>>
> >>>>>
> >>>>>
> >>>>>>>three - VCA, VCF and VCO. I'm quite sure it's not affected
by
> >>>
> >>>the
> >>>
> >>>
> >>>>>>>waveform setting either (whether I use a saw or a pulse)
but
> >>>
> >>>I'll
> >>>
> >>>
> >>>>>>>double check that tonight. The PWM setting does not make any
> >>>>>>>difference.
> >>>>>>>
> >>>>>>>Does this give you any clues? Thanks for helping!
> >>>>>>>
> >>>>>>>
> >>>>>>>--- In PolySix@yahoogroups.com, Johannes Hausensteiner
> >>>>>
> >>>>><jo.synth@c...>
> >>>>>
> >>>>>>>wrote:
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>>It is not normal that it takes 20 miuntes to tune up.
> >
> > Usually
> >
> >>>it
> >>>
> >>>
> >>>>>>>>takes about 10sec to tune and then it is quite stable.
> >>>>>>>>Check the following: hold a key down when switching power
> >
> > on.
> >
> >>>The
> >>>
> >>>
> >>>>>>>>generated note should change quite a lot until it
stabilizes
> >>>>>
> >>>>>after
> >>>>>
> >>>>>
> >>>>>
> >>>>>>>>a few secs.
> >>>>>>>>Are all six voice affected? Is the effect related to the
MG
> >>>>>
> >>>>>setting
> >>>>>
> >>>>>
> >>>>>
> >>>>>>>>(VCA/VCF/VCO)? Is it related to PWM setting?
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>Peter Andersson wrote:
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>>Hi all,
> >>>>>>>>>
> >>>>>>>>>I'm the proud new owner of a Polysix. I love it! Can't
take
> >
> > my
> >
> >>>>>>>hands
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>>>off those knobs - the filters are just great! But I'm
> >
> > having
> >
> >>>a
> >>>
> >>>
> >>>>>>>>>problem with it and I'm hoping someone can tell me what
it's
> >>>>>>>
> >>>>>>>about
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>>>and maybe even what can be done...
> >>>>>>>>>
> >>>>>>>>>After I've played the synth for a while, notes start to
go
> >>>
> >>>out
> >>>
> >>>
> >>>>>of
> >>>>>
> >>>>>
> >>>>>
> >>>>>>>>>pitch every now and then. It happens randomly every 10-30
> >
> > sec
> >
> >>>or
> >>>
> >>>
> >>>>>>>so.
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>>>The notes go off pitch with a note or so and always jump
or
> >>>>>
> >>>>>slide
> >>>>>
> >>>>>
> >>>>>
> >>>>>>>>>back to the original pitch again within half a second.
> >>>>>>>>>
> >>>>>>>>>At first I thought it was some filter setting of mine
that
> >>>>>
> >>>>>caused
> >>>>>
> >>>>>
> >>>>>
> >>>>>>>>>it, but as it turns out I get this no matter how the
Poly6
> >
> > is
> >
> >>>>>>>>>programmed (or if I use a preset or a fresh "manual"
> >
> > sound).
> >
> >>>(By
> >>>
> >>>
> >>>>>>>the
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>>>way, it takes about 20 minutes for the unit to get in
> >
> > perfect
> >
> >>>>>>>tune
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>>>after a cold start. Don't know if that's normal or if it's
> >>>>>>>
> >>>>>>>related
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>>>to this problem in any way).
> >>>>>>>>>
> >>>>>>>>>I'd be truly grateful for any help!
> >>>>>>>>>
> >>>>>>>>>Peter
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>>PolySix "Digiest" Page:
http://www.acc.umu.se/~amber/Poly6 > >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>>Yahoo! Groups Links
> >>>>>>>>>
> >>>>>>>>>To visit your group on the web, go to:
> >>>>>>>>>http://groups.yahoo.com/group/PolySix/
> >>>>>>>>>
> >>>>>>>>>To unsubscribe from this group, send an email to:
> >>>>>>>>>PolySix-unsubscribe@yahoogroups.com
> >>>>>>>>>
> >>>>>>>>>Your use of Yahoo! Groups is subject to:
> >>>>>>>>>http://docs.yahoo.com/info/terms/
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6
> >>>>>>>
> >>>>>>>Yahoo! Groups Links
> >>>>>>>
> >>>>>>>To visit your group on the web, go to:
> >>>>>>>http://groups.yahoo.com/group/PolySix/
> >>>>>>>
> >>>>>>>To unsubscribe from this group, send an email to:
> >>>>>>>PolySix-unsubscribe@yahoogroups.com
> >>>>>>>
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> >>>>>>>http://docs.yahoo.com/info/terms/
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6
> >>>>>
> >>>>>Yahoo! Groups Links
> >>>>>
> >>>>>To visit your group on the web, go to:
> >>>>>http://groups.yahoo.com/group/PolySix/
> >>>>>
> >>>>>To unsubscribe from this group, send an email to:
> >>>>>PolySix-unsubscribe@yahoogroups.com
> >>>>>
> >>>>>Your use of Yahoo! Groups is subject to:
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> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>
> >>>
> >>>
> >>>PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6
> >>>
> >>>
> >>>Yahoo! Groups Links
> >>>
> >>>To visit your group on the web, go to:
> >>> http://groups.yahoo.com/group/PolySix/
> >>>
> >>>To unsubscribe from this group, send an email to:
> >>> PolySix-unsubscribe@yahoogroups.com
> >>>
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> >>>
> >>>
> >>>
> >>>
> >
> >
> >
> > PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6
> >
> > Yahoo! Groups Links
> >
> > To visit your group on the web, go to:
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> >
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> >
> >