Hello, Thank you for the info! Best regards, Johannes Peter Andersson wrote: > Hi, > > I wanted to let you know that I've finally managed to repair my > Precious (Polysix). It was indeed the opto resistor, the PC-1, that > was faulty. It was suggested to me that I replace the old mysterious > PC-1 component with a VTL5C3 and change R93 from 4k7 to 1k2 (to get > the VTL5C3 working properly). I did and then the synth was as good > as new! > > Appearently, the PC-1 is what stabilizes the expo-converter circuit. > If it's broken, the circuit can't manage to keep the synth in tune > as the voltages vary (which is especially noticeable during the time > the machine is warming up). > > Thanks for the help! > > 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 D\ufffdnberg Electronics, who does sell this >>>> component, by entering "2sc1583" into Google >>>> >>>>* Q3 is a standard (Japanese) pnp small signal transistor, >>>> type 2SA733. D\ufffdnberg 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 >>>>>>>>> >>>>>>>>>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 >>>>>>> >>>>>>>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 >>>>> >>>>>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 >>> >>>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 > > > > > > >
Message
Re: [PolySix] Re: Notes go out of pitch
2004-02-14 by Johannes Hausensteiner