Now I see what happened... I guess that was a big mistake using the
freeze spray on such a sensitive circuit.
The problem is that I already even readjusted VR3, VR4 and VR5... So
even if and when the bad componet gets to its natural state the synth
will be out of tune ! shouldn't have touched it from the start ...
Johannes,
1. can the dual transistor get back to its initial, natural state ?
Maybe if I let the machine work a few days (so the components
can "recover" from the freeze harm - maybe by warming up ?)
2. Do VR4 (Antilog Freq.), VR3 (Antilog Width) and VR5 (Antilog
Offset) act like the VR6 (Hi Tune), VR7 (Mid Tune) and VR5 (Low
Tune) - on the Polysix new-version ? So basically if and when the
components are ok, I should be able to tune it the same way you tune
a Polysix ?
3. Last question - should the TH1 heat sensor be located just over
the multitransistor in general ? it was leaning over the circuit
board when I check it out, just realized it is a sesnor...
Thanks very much, I SHOULD fix that one it's one of a monster
beautifully sounding instrument !
--- In
PolySix@yahoogroups.com, Johannes Hausensteiner <johau@g...>
wrote:
>
> The "multileg component" probably is the dual transistor for the
> antilog amplifier. This is one of the most critical stages in terms
> of note frequency. It has an exponential transfer characteristic,
> which means that a tiny variation at the input may cause a huge at
> the output. Applying a freeze spray definitely will have a large
> effect on the tune of the instrument, but all voices are affected
> equally, because the antilog conversion is applied to the multi-
> plexed CV.
>
> gil_we wrote:
> > ooops... the multileg component is IC6, not R40
> >
> >
> > --- In PolySix@yahoogroups.com, "gil_we" <gil_we@y...> wrote:
> >
> >>Thanks guys !
> >>
> >>There was something strange going on.... After writing my
previous
> >>mail I ran over a few components with a "freeze" spray, among
them
> >>the transistors and caps area of both VCOs on the problematic
> >>oscillator and the R40 component (what looks like a mutli-leg
> >>transistor but I guess is a multi-resistor ?)
> >>
> >>Suddenly, two things happen (which still happen if I turn the
> >
> > machine
> >
> >>off for a few hours and back on... regardless internal
temperature):
> >>
> >>1. The bad oscillator is no more out of tune !
> >>
> >>2. The entire scale has changed - i.e the gap between each note
to
> >>the one that follows it is larger (there is more than one octave
> >
> > gap
> >
> >>between C4 and C5 for example)
> >>
> >>But that made me recall that when I got hte unit there was not
> >
> > tuning
> >
> >>issue at all, and the bad tuning problem on the second oscillator
> >>only started once I started servicing the machine)
> >>
> >>Strange huh ?
> >>
> >>Could it be R40 that is defective ? does that make sense ?
> >>
> >>Thanks again !
> >>
> >>
> >>
> >>
> >>
> >>--- In PolySix@yahoogroups.com, "Chromatest J. Pantsmaker"
> >><chromatest@g...> wrote:
> >>
> >>>
> >>>
> >>>replace them again? Sometimes (and it will always bite you) you
> >>
> >>put in a bunk part as a replacement.. then you spend all week
> >
> > looking
> >
> >>for something else, saying "it can't be X! I replaced X"..
> >>
> >>>
> >>>----- Original Message -----
> >>>From: gil_we <gil_we@y...>
> >>>To: PolySix@yahoogroups.com
> >>>Subject: [PolySix] Re: Trident MKII - one oscillator is out of
> >
> > tune
> >
> >>>Date: Tue, 06 Dec 2005 21:51:15 -0000
> >>>
> >>>
> >>>>You know what ?... now I relaize I replaced IC8 and ICx11 as
> >>
> >>well !
> >>
> >>>>Any other idea you can think of ?
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>--- In PolySix@yahoogroups.com, Johannes Hausensteiner
> >>
> >><johau@g...>
> >>
> >>>>wrote:
> >>>>
> >>>>>If you already replaced Rx39/Cx10 then the only thing in
> >
> > common
> >
> >>>>>for both VCOs in one voice is ICx11 (TL072). THe value of
> >
> > Rx39
> >
> >>>>>is not very critical unless it is very different to the
> >
> > nominal
> >
> >>>>>value of 1k
> >>>>>
> >>>>> > By IC8 are you refering to ICx08 ? it's a 4558 opamp.
> >>>>>No, I mean IC8, which is a 4051. It is common to all voices;
> >
> > it
> >
> >>>>>demultiplexes the CV for the VCOs
> >>>>>
> >>>>>Johannes
> >>>>>
> >>>>>
> >>>>>gil_we wrote:
> >>>>>
> >>>>>>Thanks !
> >>>>>>
> >>>>>>>The Cx10 and Rx39 have been already replaced to no avail.
> >>>>>>>By IC8 are you refering to ICx08 ? it's a 4558 opamp.
> >>>>>>>btw, I now see that I had to replace Rx36 with a slightly
> >>>>
> >>>>different
> >>>>
> >>>>>>value because even after the machine is warm enough, with
> >
> > the
> >
> >>>>>>original value the related VCO still cannot get tuned with
> >
> > the
> >
> >>>>other
> >>>>
> >>>>>>oscillators, not matter how you set the VCO tuning trimmers.
> >>>>>>
> >>>>>>>Thanks again.
> >>>>>>>--- In PolySix@yahoogroups.com, Johannes Hausensteiner
> >>>>
> >>>><johau@g...>
> >>>>
> >>>>>>wrote:
> >>>>>>
> >>>>>>>>Hi,
> >>>>>>>
> >>>>>>>The caps are Cx10 ... where x is the voice number. On the
> >>>>
> >>>>schematics
> >>>>
> >>>>>>>only voice #7 is drawn in detail, so you can see C710.
> >
> > Maybe
> >
> >>it
> >>
> >>>>is
> >>>>
> >>>>>>>not
> >>>>>>>
> >>>>>>>>the cap but the accompanying resistor (R739), or the
> >
> > demux
> >
> >>(IC8).
> >>
> >>>>>>>This is a great machine. Two really independant VCOs!
> >>>>>>>
> >>>>>>>Johannes
> >>>>>>>
> >>>>>>>
> >>>>>>>gil_we wrote:
> >>>>>>>
> >>>>>>>
> >>>>>>>>Thanks very much !
> >>>>>>>>
> >>>>>>>>The tuning is bad on both VCO1 and VCO2 of that oscillator
> >>
> >>>>>(although > >>>it seems more extreme on VCO2).
> >>>>>
> >>>>>>>>I uploaded the schematics diagram for the VCO board to the
> >>>>>
> >>>>>files >>>section - what would be the caps to check on that
> >
> > one ?
> >
> >>>>>>>>Thanks again.
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>--- In PolySix@yahoogroups.com, Johannes Hausensteiner > >
> >>>>>
> >>>>><johau@g...> > >>>wrote:
> >>>>>
> >>>>>>>>
> >>>>>>>>>Hi,
> >>>>>>>>>
> >>>>>>>>>I only have the schematics for the MK I; which I do not
> >>
> >>know > > whether
> >>
> >>>>>>>>>>it is similar to the MK II. Which VCO has the problem?
> >
> > Is
> >
> >>it
> >>
> >>>>VCO-
> >>>>
> >>>>>>>1 or
> >>>>>>>
> >>>>>>>>>>VCO-2 or both? If it is both then have a look at the
> >
> > hold
> >
> >>>>>>capacitors > >>>>after the VCO CV demux IC15 (a 4051) on
> >>>>>
> >>>>>KLM-301 board. These
> >>>>
> >>>>are
> >>>>
> >>>>>>>the
> >>>>>>>
> >>>>>>>>>>caps C25 - C32.
> >>>>>>>>>
> >>>>>>>>>Good luck,
> >>>>>>>>>
> >>>>>>>>>Johannes
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>>gil_we wrote:
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>>>I've been recovering this one, found in the flea market.
> >>>>
> >>>>Overall
> >>>>
> >>>>>>>it > >>>>>had about 8-9 different faults that I fixed,
> >>>>>
> >>>>>leaving two > > problems.
> >>>>>
> >>>>>>>>>>>The first is a bad SSM2056 chip which I need to find.
> >
> > The
> >
> >>>>second
> >>>>
> >>>>>>>i > >>>>>probably inherent in the discrete ciruit of the
> >>>>>
> >>>>>second > > oscillator.
> >>>>>
> >>>>>>>>>>>Upon powering it up, that particular oscillator will
> >
> > be
> >
> >>>>>out of > > tune, > >>>>>till it gets to its max. internal
> >>>>>temperature where the tuning > > of > >>>>>that VCO is geting
> >>>>>more or less - stable.
> >>>>>
> >>>>>>>>>>All other oscillators are immediately in tune, no matter
> >>
> >>what
> >>
> >>>>is
> >>>>
> >>>>>>>the > >>>>>temperatue inside the machine.
> >>>>>>>
> >>>>>>>>>>I, of course, tried to figure out what the bad component
> >>
> >>is
> >>
> >>>>>by >>>>>blowing with a straw on each and each of the
> >
> > suspected
> >
> >>>>>>compnents, but > >>>>>blowing on every component on the
> >>
> >>circuit
> >>
> >>>>>of that oscialltor > > which > >>>>>seems to be pitch
> >
> > related,
> >
> >>>>>seems to effect the pitch.
> >>>>>
> >>>>>>>>>>I also tried to switch transistors between the bad
> >>>>>
> >>>>>oscillator > > and > >>>>>another (working one) but the
> >
> > problem
> >
> >>>>>persisted.
> >>>>>
> >>>>>>>>>>Does anyone have any other idea / direction ?
> >>>>>>>>>>
> >>>>>>>>>>Thanks
> >>>>>>>>>>
> >>>>>>>>>>
> >>>>>>>>>>
> >>>>>>>>>>
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>
> >>>>>>>>>>>>>>PolySix "Digiest" Page:
> >>>>>
> >>>>>http://www.acc.umu.se/~amber/Poly6 > Yahoo! Groups Links
> >>>>>
> >>>>>>>>> > > > >
> >>>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6
> >>>>Yahoo! Groups Links
> >>>>
> >>>>
> >>>>
> >>>>
> >>>
> >>>
> >>>
> >>>.sig
> >>>-Chromatest J. Pantsmaker
> >>>http://www.chromatest.net
> >>>
> >>
> >
> >
> >
> >
> >
> >
> >
> > PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6
> > Yahoo! Groups Links
> >
> >
> >
> >
> >
> >
> >
> >
>