Now I got the feeling the the multitransistor has gone defected... I
let the machine work all night long, and when I check it out the
dualtransistor is not hot at all ! It used to get very hot when I let
it work for a few hours... could it just has gone defected ?
Any idea what voltages I should see on either of the legs ? Thanks
--- In PolySix@yahoogroups.com, "gil_we" <gil_we@y...> wrote:
>
> 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
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> >
>