Re: CS80 woes after storage
The issue persists without the 4050 chips.
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Here is a video of the issue if you care to watch. Hard to hold the camera and play so don't expect Stanley Kubrick.
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It may be hard to tell from this small snippet of the problem but the pitched tone it seems to either raise up? - or down in pitch until out of hearing range.
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Re: CS80 woes after storage
What I mean is, remove the IC4 & IC5 chips completely and then power on the synth without those chips on the KAS board. Does the problem still persist??
Hi Scott, I've socketed and replaced the 4050 chips but the KB control problem persists (it may have helped with the ribbon pitch issue as i'm not noticing that now).
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I'll swap out the 4006s when I lay my hands on some and report back.
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A heartfelt "thanks" for your help and pointing a novice in the right direction. Cheers mate!
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P.S. It's not for the faint of heart in there.
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Re: CS80 woes after storage
Hi Scott, I've socketed and replaced the 4050 chips but the KB control problem persists (it may have helped with the ribbon pitch issue as i'm not noticing that now).
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I'll swap out the 4006s when I lay my hands on some and report back.
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A heartfelt "thanks" for your help and pointing a novice in the right direction. Cheers mate!
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P.S. It's not for the faint of heart in there.
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Re: CS80 woes after storage
Regarding the Keyboard Control issue, the outputs are very separate and very segregated from physical pitch voltage inputs downstream, so thinking about upstream...
On the large KAS board, are the IC4 and IC5 chips socketed? Those two 4050 chips pass pitch information to the KBC cards.?If they're?in sockets you can try removing them to see if the problem goes away.
The data lines coming out of those are ganged at the inputs to the Keyboard Control cards,?so if one of the KBC cards is pulling down or shorting digital data on the KAS through the 4050's, the other KBC would certainly feel the effect as well. Those data lines connect to CD4006 shift register chips on the KBC cards; if the 4006's on the KBC cards happen to be RCA chips, those are pretty notorious for going bad. Somewhere to look anyway.
Argh... please disregard my last message. Your were onto it - the midi board was the source of a bunch of those issues.
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I received the Kenton install instructions and now I know that traces and wires were cut to do the install which caused some crazy behaviour when the kit was removed.
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A major fault does remain - the Keyboard control brilliance and level controls are causing a pitch input. I can dial in a fairly reasonable pitch and play the CS80 close to normally but outside that 'sweet spot' range is a load of dissonant shreaking that eventually goes out of hearing range as the paddles are at maximum.
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Thanks for your help, Scott. I was mulling it over all day and the coin finally dropped to have a closer look at the midi install.
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Re: CS80 woes after storage
Glad you found the issue!
I've installed a couple of those boards and I add quick disconnects (or connects as the case may be) and a set of instructions that allows the user or a tech to quickly remove the board for debugging.
I think Kenton should do something similar, especially given the very expensive midi board they sell for what it is, but they do leave it up to the customer.?
Argh... please disregard my last message. Your were onto it - the midi board was the source of a bunch of those issues.
?
I received the Kenton install instructions and now I know that traces and wires were cut to do the install which caused some crazy behaviour when the kit was removed.
?
A major fault does remain - the Keyboard control brilliance and level controls are causing a pitch input. I can dial in a fairly reasonable pitch and play the CS80 close to normally but outside that 'sweet spot' range is a load of dissonant shreaking that eventually goes out of hearing range as the paddles are at maximum.
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Thanks for your help, Scott. I was mulling it over all day and the coin finally dropped to have a closer look at the midi install.
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Re: CS80 woes after storage
I repaired a CS60 once that showed bizarre pitch issues, where controls that weren't expected to affect pitch actually did cause pitch drifts. In this case the cause was that the grounds between the various power supplies had become disconnected from each other, and so the the power rails were all just floating around relative to each other. There was a single point at a bolt/screw on the housing where all the various grounds came together, and some of the wires near that connection had broken (I assume due to vibration/handling in this case).
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jkjelec
On 04/14/2025 6:18 AM EDT Nigel99 <nigel@...> wrote:
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Argh... please disregard my last message. Your were onto it - the midi board was the source of a bunch of those issues.
?
I received the Kenton install instructions and now I know that traces and wires were cut to do the install which caused some crazy behaviour when the kit was removed.
?
A major fault does remain - the Keyboard control brilliance and level controls are causing a pitch input. I can dial in a fairly reasonable pitch and play the CS80 close to normally but outside that 'sweet spot' range is a load of dissonant shreaking that eventually goes out of hearing range as the paddles are at maximum.
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Thanks for your help, Scott. I was mulling it over all day and the coin finally dropped to have a closer look at the midi install.
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Re: CS80 woes after storage
Argh... please disregard my last message. Your were onto it - the midi board was the source of a bunch of those issues.
?
I received the Kenton install instructions and now I know that traces and wires were cut to do the install which caused some crazy behaviour when the kit was removed.
?
A major fault does remain - the Keyboard control brilliance and level controls are causing a pitch input. I can dial in a fairly reasonable pitch and play the CS80 close to normally but outside that 'sweet spot' range is a load of dissonant shreaking that eventually goes out of hearing range as the paddles are at maximum.
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Thanks for your help, Scott. I was mulling it over all day and the coin finally dropped to have a closer look at the midi install.
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Re: CS80 woes after storage
Hi Scott,
I have had a more thorough going over it and here is the symptom list:
Drone single note when midi board installed with analog in/out ribbon connected to Kenton board. All keys play the same note no matter what key is pressed. Same result both via midi and CS80 Keyboard.
If analog in/out connector is removed from Kenton midi board notes play in a single octave no matter what key is pressed from both over midi and the CS80 keyboard. The octave resets at each D key. ?The result is the same with the Kenton board removed completely.
Glissando is on full no matter how the controls are adjusted.
LFO and Sub OSC controls have no affect but will trigger over midi with the in/out ribbon from the CS80 removed from the Kenton board.
Moving the aftertouch paddles causes a pitch sweep of a few octaves or so, depending on the paddle movement. Paddle down and pitch is higher and paddle up makes the pitch of whatever note is playing, lower.? Depending on paddle position the pitch change is not noticeable e.g. brilliance paddles up there is no pitch sweep but when the level paddles are at middle position notes can be heard. I’m assuming that they scale out of hearing range when the Level paddles are fully down as I can’t hear anything.
All of that makes it very hard to actually understand what is going on with the synth. With short attack a blip will play but sometimes a single note will sustain randomly here an there. It seems like the Attack slider is controlling the sustain time.
Mostly if I place a finger on the pitch ribbon I get a random crazy high or low note but in some cases I get a clean note that if I hold my finger in place on the pitch ribbon, with my other hand I can play the synth normally with chords and everything and mostly in tune. Should I play an 8 note chord, it will sound within the realm of decent and in tune.
I’m losing my mind. If anyone else feels these issues look familiar please drop me line. It would be much appreciated.?
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On 14 Apr 2025, at 3:09?am, Scott Rodriguez via groups.io <synthrodriguez@...> wrote:
Thinking about this some more and the way it's behaving, it sounds like the Kenton board may be the problem.
It's hard to imagine a non-Kenton unit displaying those mannerisms?and all of the items you called out are related to Kenton functions.
Maybe try pulling and re-seating all the Kenton board connectors. On Sun, Apr 13, 2025 at 12:59?PM Scott Rodriguez via <synthrodriguez= gmail.com@groups.io> wrote: Those are some weird issues. As always, step 1 is to verify power. Use a meter to check for voltage and ripple or better yet use a scope.
+15, -15,?+10.6, -6.5,?+8.5 should all be pretty close. If so, move on. If not, you found where to start! :)
Hi CS80 gurus, owners and fans.?
I have a CS80 with Kenton midi that I have owned since 2012 and recently put into storage for three years. The synth was working fine prior to storing but now there are a range of strange, possibly interconnected, issues. I’ll try and describe yhem
as best I can.?
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On powering up a single octave plays whatever keys you press on the keyboard.? For instance no matter what C key that I press it’s all the same octave etc.?
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The LFO doesn’t seem to work at all and the aftertouch brightness high and low paddle causes a pitch change.
maybe most telling when a select some preset buttons a random third button will light.?
Weirdly, at one stage I held the ribbon at a particular spot and was able to play the synth more or less normally.?
There may be more weirdness that I’m yet to discover but these are the main symptoms. I’m reasonably techy and have a scope but it would be great to get some ideas of where to start.
?
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Re: CS80 woes after storage
Hi Scott, thanks for your input.
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I'll verify the PSU today. I suspected the Kenton board as well and removed the board and the issues are the same.? I've checked the installation for shorts or wiring issues and it all seems fine. It was installed by Kent and i've had no issues with the midi or the synth in 10 years.
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In it's current state the CS80 is not responding to LFO or SUB OSC aftertouch controls from it's own keyboard but if I trigger notes over midi these functions are working.? It's a real head-scratcher.
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I'm wondering about the possibility of a failed IC or diode in the preset panel that could be sending mixed signals or failure in the BA board.?
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I'm trying not to go straight into freak-out mode and suspect a YM26XX IC but it's hard with this many seemingly unrelated issues.??
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Re: CS80 woes after storage
Thinking about this some more and the way it's behaving, it sounds like the Kenton board may be the problem.
It's hard to imagine a non-Kenton unit displaying those mannerisms?and all of the items you called out are related to Kenton functions.
Maybe try pulling and re-seating all the Kenton board connectors.
On Sun, Apr 13, 2025 at 12:59?PM Scott Rodriguez via <synthrodriguez= gmail.com@groups.io> wrote: Those are some weird issues. As always, step 1 is to verify power. Use a meter to check for voltage and ripple or better yet use a scope.
+15, -15,?+10.6, -6.5,?+8.5 should all be pretty close. If so, move on. If not, you found where to start! :)
Hi CS80 gurus, owners and fans.?
I have a CS80 with Kenton midi that I have owned since 2012 and recently put into storage for three years. The synth was working fine prior to storing but now there are a range of strange, possibly interconnected, issues. I’ll try and describe yhem
as best I can.?
?
On powering up a single octave plays whatever keys you press on the keyboard.? For instance no matter what C key that I press it’s all the same octave etc.?
?
The LFO doesn’t seem to work at all and the aftertouch brightness high and low paddle causes a pitch change.
maybe most telling when a select some preset buttons a random third button will light.?
Weirdly, at one stage I held the ribbon at a particular spot and was able to play the synth more or less normally.?
There may be more weirdness that I’m yet to discover but these are the main symptoms. I’m reasonably techy and have a scope but it would be great to get some ideas of where to start.
?
?
?
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Re: CS80 woes after storage
Those are some weird issues. As always, step 1 is to verify power. Use a meter to check for voltage and ripple or better yet use a scope.
+15, -15,?+10.6, -6.5,?+8.5 should all be pretty close. If so, move on. If not, you found where to start! :)
Hi CS80 gurus, owners and fans.?
I have a CS80 with Kenton midi that I have owned since 2012 and recently put into storage for three years. The synth was working fine prior to storing but now there are a range of strange, possibly interconnected, issues. I’ll try and describe yhem
as best I can.?
?
On powering up a single octave plays whatever keys you press on the keyboard.? For instance no matter what C key that I press it’s all the same octave etc.?
?
The LFO doesn’t seem to work at all and the aftertouch brightness high and low paddle causes a pitch change.
maybe most telling when a select some preset buttons a random third button will light.?
Weirdly, at one stage I held the ribbon at a particular spot and was able to play the synth more or less normally.?
There may be more weirdness that I’m yet to discover but these are the main symptoms. I’m reasonably techy and have a scope but it would be great to get some ideas of where to start.
?
?
?
|
Hi CS80 gurus, owners and fans.?
I have a CS80 with Kenton midi that I have owned since 2012 and recently put into storage for three years. The synth was working fine prior to storing but now there are a range of strange, possibly interconnected, issues. I’ll try and describe yhem
as best I can.?
?
On powering up a single octave plays whatever keys you press on the keyboard. ?For instance no matter what C key that I press it’s all the same octave etc.?
?
The LFO doesn’t seem to work at all and the aftertouch brightness high and low paddle causes a pitch change.
maybe most telling when a select some preset buttons a random third button will light.?
Weirdly, at one stage I held the ribbon at a particular spot and was able to play the synth more or less normally.?
There may be more weirdness that I’m yet to discover but these are the main symptoms. I’m reasonably techy and have a scope but it would be great to get some ideas of where to start.
?
?
?
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Re: Do we have a list off all the errors in the calibration manual?
Hey Michael and everyone, I am indeed part of the group and thanks for chiming me in :)
As Michael stated, the resonance seems to “collapse” when you adjust too far, but iirc I noticed if you raise the brilliance paddle up to top then back to centre you can “regain” the level and continue from where you had it collapse, allowing it to go further up in p-p voltage. ?Hope that makes sense! ?
The one observation I noticed doing it this way however is the relationship of this calibration to the brilliance paddle movement. For example once calibrated to a higher p-p voltage, raising the paddle from middle to top then back to middle keeps the maximum resonance centred—however lowering the paddle to bottom and back to middle the balance point becomes offset and collapsed(the maximum slightly higher than the detent point). ?It makes me think that what we are actually trying to achieve here with this calibration is a bipolar balance so moving the paddle to either extreme and back to the detent we can keep the maximum level at the detent position if that makes sense. ?Not sure what p-p voltage that would be in certain CS80’s, maybe closer to the CS60 values as Michael was experimenting with, but just my own theory.
Anyway… Someone out there must be holding some secret Yamaha documents about this calibration between revisions though, I find it too strange how this particular calibration was so off in the CS80 I had here.
Greg C.
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On Nov 11, 2024, at 3:16?PM, Michael Fuchs via groups.io <yahoogroups@...> wrote:
Hi Mike,
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MFox here. :)
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Just a few additional words. I was really struggeling with the resonance, it always collapsed when I dialed it to the specs, but not on every voiceboard, some made it collapse earlier some later. Joachim Wilson (also a member of this group) was able to push it further. In the end I decided to go with the of the CS60 procedure for the filter and maybe adjust it a little more towards the CS80 specs until it worked fine on every voice board. Not sure what sound nuance I am missing, but the good thing is it still sounds like a CS80. ;)
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Not sure if Greg is also a member of the group, but he was also seeing this during his calibration and tried to figure out a solution. He was telling me, that he calibrated the HPF to 4.3V and then cycled back to the same note, rised the brilliance level all the way up and then back down to the center. There is a level loss, but it sounded in the end right to him. Maybe you can try out that approach.
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Michael
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Re: Do we have a list off all the errors in the calibration manual?
Hi Mike,
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MFox here. :)
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Just a few additional words. I was really struggeling with the resonance, it always collapsed when I dialed it to the specs, but not on every voiceboard, some made it collapse earlier some later. Joachim Wilson (also a member of this group) was able to push it further. In the end I decided to go with the of the CS60 procedure for the filter and maybe adjust it a little more towards the CS80 specs until it worked fine on every voice board. Not sure what sound nuance I am missing, but the good thing is it still sounds like a CS80. ;)
?
Not sure if Greg is also a member of the group, but he was also seeing this during his calibration and tried to figure out a solution. He was telling me, that he calibrated the HPF to 4.3V and then cycled back to the same note, rised the brilliance level all the way up and then back down to the center. There is a level loss, but it sounded in the end right to him. Maybe you can try out that approach.
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Michael
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Re: Do we have a list off all the errors in the calibration manual?
Hello Mike, I have a CS-80 that repaired long, long time ago,
more than 20 years....
I have the tech manual, but it is very far from me, now. to see
it and go to the point. But I remember one thing that you can use.
You are trying to calibrate a board that you have changed
components, right?. So look for a pattern that repeats on boards
that do not have suffered a modification and is ok. I suppose that
having 16 OSCILLATORS, you could find some that are OK. I remember
that some parameters are affected by the way you touch the
keyboard.... so I build a simulator of the mechanism with relays
(for replacing the switches) and 555 to simulate it in a
predictable way.
GOOD LUCK!
Gustavo.
On 2024-11-11 10:20 AM, Scott Rodriguez
via groups.io wrote:
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Mike: For the CS-80, when referencing the Adjustment
Procedure?document, below is what I have learned about the
typos and inaccuracies on the filter and vca adjustment docs and
how I do it.
VCF - Complete Alignment - Page 11
?Make sure to do the sustain level and attack adjustment
procedures first.
When doing the?adjustment, I use two trimmers at the same time
and adjust the peak and gain pots simultaneously. Makes setting
the?High Pass filter quick and easy.
If you can't achieve the correct voltage settings
(sometimes you can ALMOST get there, argh) then you have a bad
chip. Good chips will easily hit the intended target level
every time.
Item 1. The CP3 terminal reference is
incorrect?and should be CP2. I use CP7 however which is
electrically the same thing; it's just easier to get at the
way I do it.
The 4.3 Vp-p value is incorrect and is the zero-to-peak
value. The correct value is double that and should be 8.6
V peak-to-peak to match the pictorial representation.
Item 2.??The terminal reference of CP3 is
incorrect and should be CP8. The 2.2 Vp-p value in the
pictorial is correct.
VCA - Page 15
Make sure you have a good ground reference for the
scope on the card itself. If using a rack mounting
ear, make sure the screw is good and tight (which
should be done anyway).
Item 2. VCA #2 Gain - As shown, but set both
the BRILLIANCE and RESONANCE paddles on the main panel
to the full forward (the low) position to achieve the
correct wave shape.
Item 4. Output Terminal - Rather than using a
scope for adjusting the output VCA to 80,mVp-p,?use a
good DMM and set it to dBm. Adjust the trimmer to a
28.3 mV RMS value. Much easier to do and more
consistent between voices.
Also, lately I've been replacing the voice card
2SC458 output transistor with KSC1815 parts as I've
seen several go bad. Drop-in replacement with a lower
noise figure. Yamaha went to the 1815's for the CS-70M
cards, fwiw.?
Scott Rodriguez
11/11/24
I'm asking this question basically to see how people have
approached the filter and VCA tuning discrepancies in the
service manual.? I've read several different opinions on
them, but have yet to find a consensus or a correct answer.?
I've got two CS-80s here right now to experiment on.? One of
them I probably calibrated somewhat wrong over a decade ago
and could probably use a new calibration.??
?
Here's the latest take:
?
?
Thoughts?
?
-Mike Borish
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Re: Do we have a list off all the errors in the calibration manual?
Mike: For the CS-80, when referencing the Adjustment Procedure?document, below is what I have learned about the typos and inaccuracies on the filter and vca adjustment docs and how I do it. VCF - Complete Alignment - Page 11
?Make sure to do the sustain level and attack adjustment procedures first. When doing the?adjustment, I use two trimmers at the same time and adjust the peak and gain pots simultaneously. Makes setting the?High Pass filter quick and easy. If you can't achieve the correct voltage settings (sometimes you can ALMOST get there, argh) then you have a bad chip. Good chips will easily hit the intended target level every time. Item 1.
The CP3 terminal reference is incorrect?and should be CP2. I use CP7 however which is electrically the same thing; it's just easier to get at the way I do it. The 4.3 Vp-p value is incorrect and is the zero-to-peak value. The correct value is double that and should be 8.6 V peak-to-peak to match the pictorial representation. Item 2.??The terminal reference of CP3 is incorrect and should be CP8. The 2.2 Vp-p value in the pictorial is correct.
VCA - Page 15 Make sure you have a good ground reference for the scope on the card itself. If using a rack mounting ear, make sure the screw is good and tight (which should be done anyway).
Item 2. VCA #2 Gain - As shown, but set both the BRILLIANCE and RESONANCE paddles on the main panel to the full forward (the low) position to achieve the correct wave shape.
Item 4. Output Terminal - Rather than using a scope for adjusting the output VCA to 80,mVp-p,?use a good DMM and set it to dBm. Adjust the trimmer to a 28.3 mV RMS value. Much easier to do and more consistent between voices.
Also, lately I've been replacing the voice card 2SC458 output transistor with KSC1815 parts as I've seen several go bad. Drop-in replacement with a lower noise figure. Yamaha went to the 1815's for the CS-70M cards, fwiw.?
Scott Rodriguez
11/11/24
I'm asking this question basically to see how people have approached the filter and VCA tuning discrepancies in the service manual.? I've read several different opinions on them, but have yet to find a consensus or a correct answer.? I've got two CS-80s here right now to experiment on.? One of them I probably calibrated somewhat wrong over a decade ago and could probably use a new calibration.??
?
Here's the latest take:
?
?
Thoughts?
?
-Mike Borish
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CS-80 Coming Up For Sale -Borish Electroncs-
I'm just putting the finishing touches on a CS-80 planned for sale in Chicago, IL USA.? I've really gone over almost everything in this one.? All new electrolytic caps, all new CMOS, full calibration, etc.? Leg bag, lid and legs included.? Pictures coming soon.??
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You can e-mail me at mike@... with offers if you're interested.?? ?
Thanks,
-Mike
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Do we have a list off all the errors in the calibration manual?
I'm asking this question basically to see how people have approached the filter and VCA tuning discrepancies in the service manual.? I've read several different opinions on them, but have yet to find a consensus or a correct answer.? I've got two CS-80s here right now to experiment on.? One of them I probably calibrated somewhat wrong over a decade ago and could probably use a new calibration.??
?
Here's the latest take:
?
?
Thoughts?
?
-Mike Borish
borishelectronics.com
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Re: How long can your CS80 go until the need of recalibrating the oscillators?
Hi. I have had 3 CS80s in the studio, once they have settled in for a few days, I do the complete calibration. I calibrated all three once a year, but just to get the beats the way I like them, otherwise they were playable without problems. In the last ten years I have only kept one, since I moved to the seaside, I thought I would have problems, but once the tuning has been done , I repeat it for my pleasure, just once a year.
Il giorno mer 24 gen 2024 alle ore 18:51 Michael Fuchs < yahoogroups@...> ha scritto: Hi All,
since there seems to come back some life into the group, I was always wondering about one thing: Before I had a CS80 I was always reading about what a headache the machine is regarding staying in tune over time. Some technician even told me once that just by moving it around in the room detuned some oscillators.
I haven't made that experience. Actually I calibrated mine from ground up, which was quite a ride that will cost me a few years of my lifespan, but I learned a lot. I documented it, mainly for myself if I have to ever do it again :) , in case of interest : Anyway, I calibrated mine in 2016, meanwhile I also moved to another apartment. I recently checked how good it is in tune and it is slightly detuned here and there, but it is not bad and I cannot really hear it when playing.
I wonder about my fellow CS80 owners what experience they make or made regarding this.?
Michael
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Re: How long can your CS80 go until the need of recalibrating the oscillators?
Honestly it should have gone for more. ?Selling the dream of owning a CS-80 with a view of downtown Los Angeles is right out of the film Blade Runner. ?This experience is completely priceless.?
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On Jan 24, 2024, at 11:28?AM, Stan Valiulis <scvaliulis@...> wrote:
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Hi All,
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I am going to unsubscribe because I sold my CS80 a couple of years ago.? I am not a tech and it was very needy and hard to move.? FYI, I sold it for $47,000.00 to some film person
out West.
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Best of luck to all of you.? These are amazing instruments.
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Stan
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From:
yamahaCS80fans@groups.io <yamahaCS80fans@groups.io> on behalf of Scott Rodriguez <synthrodriguez@...>
Date: Wednesday, January 24, 2024 at 1:24?PM
To: yamahaCS80fans@groups.io <yamahaCS80fans@groups.io>
Subject: Re: [yamahaCS80fans] How long can your CS80 go until the need of recalibrating the oscillators?
If otherwise in well-calibrated and good operating?condition, and in a stable environment, about once-a-year tuning is pretty typical. Much like a piano.
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Nigel99