Yahoo Groups archive
Thread
2010-02-06 by Alexis V. Rogers
One of the voices on a PolySix I'm looking at does not sound when the VCA switch is set to EG. It does sound when the switch is set to waveform. I tried swapping IC34 SSM2056 on that voice with another working voice but the problem did not follow. Does anyone have any suggestions on where else to look? Thanks, Alex
2010-02-07 by Andrew Jury
Hi, When you switch to EG mode does this non-sounding voice still light the LED? As a generic answer, you might want to perform some comparative measurements around bi-lateral switch IC35 and around emitter follower stage Q5 with the other working voices. My guess is that there is a problem somewhere in this vicinity. Good luck and don¹t forget to tell us how you get on. Cheers, Andy On 06/02/2010 22:49, "Alexis V. Rogers" <alexis.v.rogers@gmail.com> wrote: > > > > > > One of the voices on a PolySix I'm looking at does not sound when the VCA > switch is set to EG. It does sound when the switch is set to waveform. I tried > swapping IC34 SSM2056 on that voice with another working voice but the problem > did not follow. Does anyone have any suggestions on where else to look? > Thanks, Alex > > > > > [Non-text portions of this message have been removed]
2010-02-07 by Alexis V. Rogers
The LED does light on that voice. I checked voltages on IC35 and Q5 as you suggested and found two discrepencies with the other working voices. I'm measuring -1.495V on pin 1 of IC35 on the problematic voice, where I get -0.02ish on pin 1 on the working voices. Also, I'm getting -1.2V on the base of Q5 where I'm getting around -0.02V on the bases of Q5 on every other voice. --- In PolySix@yahoogroups.com, Andrew Jury <andy@...> wrote:
> > Hi, > > When you switch to EG mode does this non-sounding voice still light the LED? > As a generic answer, you might want to perform some comparative measurements > around bi-lateral switch IC35 and around emitter follower stage Q5 with the > other working voices. My guess is that there is a problem somewhere in this > vicinity. > > Good luck and don¹t forget to tell us how you get on. > > Cheers, > Andy > >
2010-02-12 by Andrew Jury
Check the none of the transistor have leaky junctions, but failing that swap IC35! On 07/02/2010 21:02, "Alexis V. Rogers" <alexis.v.rogers@gmail.com> wrote: > > > > > > The LED does light on that voice. I checked voltages on IC35 and Q5 as you > suggested and found two discrepencies with the other working voices. I'm > measuring -1.495V on pin 1 of IC35 on the problematic voice, where I get > -0.02ish on pin 1 on the working voices. Also, I'm getting -1.2V on the base > of Q5 where I'm getting around -0.02V on the bases of Q5 on every other voice. > > --- In PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com> , Andrew > Jury <andy@...> wrote: >> > >> > Hi, >> > >> > When you switch to EG mode does this non-sounding voice still light the >> LED? >> > As a generic answer, you might want to perform some comparative >> measurements >> > around bi-lateral switch IC35 and around emitter follower stage Q5 with the >> > other working voices. My guess is that there is a problem somewhere in this >> > vicinity. >> > >> > Good luck and don¹t forget to tell us how you get on. >> > >> > Cheers, >> > Andy >> > >> > > > > > > [Non-text portions of this message have been removed]
2010-02-13 by Alexis V. Rogers
Q5 and Q6 are fine. I swapped out IC35 but the voice still doesn't sound when the VCA is set to EG mode. When set to gate mode, it sounds slightly lower in volume than the other voices and is a little flat. I'm stumped. I've also looked for a cracked solder joints to no avail. --- In PolySix@yahoogroups.com, Andrew Jury <andy@...> wrote:
> > Check the none of the transistor have leaky junctions, but failing that swap > IC35! > > > On 07/02/2010 21:02, "Alexis V. Rogers" <alexis.v.rogers@...> wrote: > > > > > > > > > > > > > The LED does light on that voice. I checked voltages on IC35 and Q5 as you > > suggested and found two discrepencies with the other working voices. I'm > > measuring -1.495V on pin 1 of IC35 on the problematic voice, where I get > > -0.02ish on pin 1 on the working voices. Also, I'm getting -1.2V on the base > > of Q5 where I'm getting around -0.02V on the bases of Q5 on every other voice. > > > > --- In PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com> , Andrew > > Jury <andy@> wrote: > >> > > >> > Hi, > >> > > >> > When you switch to EG mode does this non-sounding voice still light the > >> LED? > >> > As a generic answer, you might want to perform some comparative > >> measurements > >> > around bi-lateral switch IC35 and around emitter follower stage Q5 with the > >> > other working voices. My guess is that there is a problem somewhere in this > >> > vicinity. > >> > > >> > Good luck and don¹t forget to tell us how you get on. > >> > > >> > Cheers, > >> > Andy > >> > > >> > > > > > > > > > > > > > > > [Non-text portions of this message have been removed] >
2010-02-13 by Andrew Jury
Oh dear! Guess you are going to have to make exhaustive comparative checks between working and the non-working voice to get to the bottom of this one. It would be interesting at this point to ensure C50 is OK and that the filter cut off bias voltage at pin 13 of IC32 doesn¹t vary to wildly from the others. Cheers, Andy On 13/02/2010 07:27, "Alexis V. Rogers" <alexis.v.rogers@gmail.com> wrote: > > > > > > Q5 and Q6 are fine. I swapped out IC35 but the voice still doesn't sound when > the VCA is set to EG mode. When set to gate mode, it sounds slightly lower in > volume than the other voices and is a little flat. I'm stumped. I've also > looked for a cracked solder joints to no avail. > > --- In PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com> , Andrew > Jury <andy@...> wrote: >> > >> > Check the none of the transistor have leaky junctions, but failing that >> swap >> > IC35! >> > >> > >> > On 07/02/2010 21:02, "Alexis V. Rogers" <alexis.v.rogers@...> wrote: >> > >>> > > >>> > > >>> > > >>> > > >>> > > >>> > > The LED does light on that voice. I checked voltages on IC35 and Q5 as you >>> > > suggested and found two discrepencies with the other working voices. I'm >>> > > measuring -1.495V on pin 1 of IC35 on the problematic voice, where I get >>> > > -0.02ish on pin 1 on the working voices. Also, I'm getting -1.2V on the >>> base >>> > > of Q5 where I'm getting around -0.02V on the bases of Q5 on every other >>> voice. >>> > > >>> > > --- In PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com> >>> <mailto:PolySix%40yahoogroups.com> , Andrew >>> > > Jury <andy@> wrote: >>>>> > >> > >>>>> > >> > Hi, >>>>> > >> > >>>>> > >> > When you switch to EG mode does this non-sounding voice still light the >>>> > >> LED? >>>>> > >> > As a generic answer, you might want to perform some comparative >>>> > >> measurements >>>>> > >> > around bi-lateral switch IC35 and around emitter follower stage Q5 >>>>> with the >>>>> > >> > other working voices. My guess is that there is a problem somewhere >>>>> in this >>>>> > >> > vicinity. >>>>> > >> > >>>>> > >> > Good luck and don¹t forget to tell us how you get on. >>>>> > >> > >>>>> > >> > Cheers, >>>>> > >> > Andy >>>>> > >> > >>>>> > >> > >>> > > >>> > > >>> > > >>> > > >>> > > >> > >> > >> > >> > [Non-text portions of this message have been removed] >> > > > > > > [Non-text portions of this message have been removed]
2010-02-16 by Alexis V. Rogers
C50 is fine. And the bias voltage at pin 13 of IC32 is .02V on the dead voice and -.04V on the working voices. --- In PolySix@yahoogroups.com, Andrew Jury <andy@...> wrote:
> > Oh dear! Guess you are going to have to make exhaustive comparative checks > between working and the non-working voice to get to the bottom of this one. > It would be interesting at this point to ensure C50 is OK and that the > filter cut off bias voltage at pin 13 of IC32 doesn¹t vary to wildly from > the others.
2010-02-24 by Alexis V. Rogers
Okay, I've checked everything on the voice and here are the discrepencies. There is -1.2V at the junction of R218, R217, C50, and IC 35 pin 1. There is -1.2V across R217 to IC24 pin 1. There is also -1.2V at IC35 pin 2 and across the series of resistors connected to that pin from R141, R142, R143, R135 and the base of Q6. When I hit a key to trigger this voice, D10 lights and the -1.2V on IC35 pins 1 and 2 goes up to -0.9V. I removed IC35 from the socket (with the synth off of course) and performed additional measurements. With no IC in the socket I get -5V on pin 1 and a few mV on pin 2. I'm not sure what to make of all this. Thanks for any help. --- In PolySix@yahoogroups.com, Andrew Jury <andy@...> wrote:
> > Oh dear! Guess you are going to have to make exhaustive comparative checks > between working and the non-working voice to get to the bottom of this one. > It would be interesting at this point to ensure C50 is OK and that the > filter cut off bias voltage at pin 13 of IC32 doesn¹t vary to wildly from > the others. > > Cheers, > Andy
2010-02-24 by Andrew Jury
The intense feeling of wanting to smash the thing will pass when you eventually discover the problem, I promise! Have you tried swapping both IC32 and 34 from another voice as a pair? Can¹t remember if we tried this? Also can you verify that VR9 is still a 1M trimmer and has a range which adjusts accordingly. Mark the position of it¹s current setting before you start. This pots have a horrible habit of going dead where the wiper sits on the carbon track for nearly 30 years! If I have some spare time (ha!) I¹ll go into the lab and takes some readings on one of mine... Cheers, Andy On 24/02/2010 15:25, "Alexis V. Rogers" <alexis.v.rogers@gmail.com> wrote: > > > > > > Okay, I've checked everything on the voice and here are the discrepencies. > There is -1.2V at the junction of R218, R217, C50, and IC 35 pin 1. There is > -1.2V across R217 to IC24 pin 1. There is also -1.2V at IC35 pin 2 and across > the series of resistors connected to that pin from R141, R142, R143, R135 and > the base of Q6. > > When I hit a key to trigger this voice, D10 lights and the -1.2V on IC35 pins > 1 and 2 goes up to -0.9V. > > I removed IC35 from the socket (with the synth off of course) and performed > additional measurements. With no IC in the socket I get -5V on pin 1 and a few > mV on pin 2. > > I'm not sure what to make of all this. > > Thanks for any help. > > --- In PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com> , Andrew > Jury <andy@...> wrote: >> > >> > Oh dear! Guess you are going to have to make exhaustive comparative checks >> > between working and the non-working voice to get to the bottom of this one. >> > It would be interesting at this point to ensure C50 is OK and that the >> > filter cut off bias voltage at pin 13 of IC32 doesn¹t vary to wildly from >> > the others. >> > >> > Cheers, >> > Andy > > > > > [Non-text portions of this message have been removed]
2010-02-25 by Alexis V. Rogers
Thanks again Andy. The frustration has passed. The conformal coating on the PCB was breaking down and there were a few shorts and spotty connections on the PCB itself. I cleaned it all up and ran a few jumper wires, and now everything works as it should. --- In PolySix@yahoogroups.com, Andrew Jury <andy@...> wrote:
> > The intense feeling of wanting to smash the thing will pass when you > eventually discover the problem, I promise! Have you tried swapping both > IC32 and 34 from another voice as a pair? Can¹t remember if we tried this? > Also can you verify that VR9 is still a 1M trimmer and has a range which > adjusts accordingly. Mark the position of it¹s current setting before you > start. This pots have a horrible habit of going dead where the wiper sits on > the carbon track for nearly 30 years! > > If I have some spare time (ha!) I¹ll go into the lab and takes some readings > on one of mine... > > Cheers, > Andy
2010-02-25 by Andrew Jury
Well done! Persistence always pays off! Cheers, Andy On 25/02/2010 17:48, "Alexis V. Rogers" <alexis.v.rogers@gmail.com> wrote: > > > > > > Thanks again Andy. The frustration has passed. The conformal coating on the > PCB was breaking down and there were a few shorts and spotty connections on > the PCB itself. I cleaned it all up and ran a few jumper wires, and now > everything works as it should. > > --- In PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com> , Andrew > Jury <andy@...> wrote: >> > >> > The intense feeling of wanting to smash the thing will pass when you >> > eventually discover the problem, I promise! Have you tried swapping both >> > IC32 and 34 from another voice as a pair? Can¹t remember if we tried this? >> > Also can you verify that VR9 is still a 1M trimmer and has a range which >> > adjusts accordingly. Mark the position of it¹s current setting before you >> > start. This pots have a horrible habit of going dead where the wiper sits >> on >> > the carbon track for nearly 30 years! >> > >> > If I have some spare time (ha!) I¹ll go into the lab and takes some >> readings >> > on one of mine... >> > >> > Cheers, >> > Andy > > > > > [Non-text portions of this message have been removed]
2010-04-23 by Paul T
My polysix keys don't work right. It's it's only real fault at this time, having repaired my PCB and done the battery mod/rechip all is well there. I know you can get the brush on contact stuff, and any other number of things you can try to repair a keyboard that doesn't fully work up and down the notes. It is a contact issue (not the electronics) in my case. I was wondering how 'easy' it would be to graft on another synths keyboard, say from a JX-8P which I've got laying around, the Polysix is more important to me so I wouldn't mind taking the JX's keyboard, modifying the electronics where needed and plugging/hacking it onto the polysix so that the (working) JX-8P keys would then play the Polysix. I could even use the aftertouch of the JX keys and rig it up somehow to the mod or some other function as an added bonus. JX keys aren't the best but they are way more solid than polysix (mine are semi weighted, not all 8P keys are). I'm sure there must be a way, in an ideal world it would simply be a case of checking voltages/triggers from the current keybed and mapping it to the JX's keybed, but I'm not sure if any micro controllers are involved that dictate a 'matrix' of which keys are pressed and how it differes from the JX. I also have a DX7 2, SY85 keyboard sitting around I could try if they are easier, but was thinking of breaking the 8P to make a custom rackmount from it anyway. I'm not so concerned about the physical side of fitting the keyboard into the polysix at this time, I'll cross that bridge when/if I come to it.. for now i'm talking purely about functionality and electronics and if it sounds possible? Any ideas are welcome. Thanks Paul _________________________________________________________________ http://clk.atdmt.com/UKM/go/197222280/direct/01/ Do you have a story that started on Hotmail? Tell us now [Non-text portions of this message have been removed]
2010-04-23 by Dave Garfield
Hi Paul,
Bob Weigel of Sounddoctorin.com has come up with a good fix for those ol' nasty Panasonic-type bubble switches. He found a material used by NASA that's as conductive as the carbon buttons, backed by 3M adhesive. He sells kits of these little conductive "dots" at his synth repair website, http://www.sounddoctorin.com. He also has an instructional video on how to apply them on YouTube.com.
While I've not used these personally, there is testimonial on his site as to their effectiveness, and Bob himself reports that he's fixed various Korg Poly- machines and a few other keyboards that use them (Polysix, Poly 61, '61M, Memorymoog), and they've lasted over a year (They're still being observed in use, as he only recently came up with these).
Now, Bob Weigel is a friend of mine, but I think that this is an important enough fix to set aside any personal relationships in favor of providing relief to a very aggravating quirk of these wonderful instruments. Sorry to sound like a commercial.
All the best,
Dave Garfield
[Non-text portions of this message have been removed]