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Re: CS-80 + FC7
开云体育I remember this, but, afair, ?it used to work. Perhaps better to eliminate that pedal, in any case…
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Re: CS-80 + FC7
开云体育the original CS80 volume pedal was a lightbulb and photocell with a teardrop? shaped dowser to limit light to the photo cell... I have yet to try my FC7s on my 80 as I once had ground rail burn out with a faulty connector short on the expression jack.... there is voltage there to power a bulb... ---- On Mon, 22 Jan 2018 15:22:18 -0600 Fernando Zarone fernandozarone@... [yamahacs80] wrote ----
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CS-80 + FC7
Hi all.?
After one year (moved to a new house) I switched my CS-80 on and fortunately everything still works fine, but the FC-7 connected to it. The malfunction is: when I push the pedal forward ?it raises the volume /wha-wha regularly, but when I go back down to the “low “ position, the volume takes some seconds before fading. In other words, when used fot raising the volume it works, when lowering it, it is … delayed. Like a long release…? Any clue? Thanks Fernando ? |
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Re: YM26600/26700 IC Alternatives
Thanks, gentlemen, you've given me some hope, as I fear I may have fried my 26600 either by static discharge or by touching the +15V card riser rail against the keyboard PCB's (now I know to pull the keyboard toward the front before lowering the riser! Ugh..) . Even if I can find an original replacement (there's currently a 26700 on Ebay for $850!), or a donor CS-60, in the end it'll still be a fragile 40-year-old chip I'm throwing in there.
Old Crow's actually the tech that serviced this particular CS-80 back in '13. All new 4000-series IC's throughout. |
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Re: YM26600/26700 IC Alternatives
开云体育Beside what David said - yes, someone did it already: Ok, it is not for the polyphonic series, but it shows, that is doable, and also that it would provide other advantages, like adding MIDI.On 16.01.18 18:39 , jonathan4051@... [yamahacs80] wrote: ? |
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Re: YM26600/26700 IC Alternatives
开云体育Jonathan,Duplicating the logic is easy. ?The big pain is the voltage. ?The Yamaha uses 4000-series CMOS and runs all the digital logic at +8.5 / -6.5 -> 15 volt supply. ?It’s offset above/below zero to interface with the analog circuits that run off +/- 15 volt. ?No modern chips run at this high voltage. ?Even 5-volt is history and 3.3-volt is only kept around for interfacing with older parts. ?All the chip guts these days are running around 1-volt. ? So, you end up needing tons of level-shifting chips to connect the Ardiuno (or FPGA) to the rest of the logic. ?Most circuits I’ve seen use chips that were intended for converting RS-232 (also fairly extinct) like the MAX232. ?The chips that were most commonly used won’t work anymore since they convert to +5v TTL. ?David
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Re: CS-80 tech question: initial velocity problem on TSB board
I checked the voltages at the 4051 key input pins
(13-15, 1, 2, and 5), and they do not look reasonable. Whilst healthy
keys on other 4051's rest at 6V and approach 13-14V as you apply aftertouch, the bad
keys are resting at 9.23V and jump to 15.49V as soon as they are hit,
without even applying the aftertouch. The voltages on some of them
slowly drop back toward 9.23 until you hit them again and they jump back
to 15.49V. Odd.
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Re: CS-80 tech question: initial velocity problem on TSB board
Hi David,
Thanks for the info and happy new year to you as well! This is actually the second time you've helped me, as I've been going by the CS-80 schematics and block diagrams from your website - thanks for uploading those! I do have an oscilloscope, so will give it a whirl, and will try removing IC4 and see if pin 3 is still +15v. I'm also wondering what effect the TKC board has on the A, B, and C inputs of the 4051, and if that could be the culprit. One guy on Muffwiggler suggested a possible broken trace or wire going to the aftertouch PCB under the keyboard, and that if the -15v rail wasn't getting to this board, +15v at pin 3 could be the symptom. Another said to simply wiggle all the spider webs of wires going to the solder pads, as they can detach over time. So I have a few things to try. That thread can be found here: https://www.muffwiggler.com/forum/viewtopic.php?t=193847 For some reason, the last tech that serviced this board installed JRC 072BD's in place of the old 4558's. Am not sure if this is a common swap, but the design on their respective data sheets looked pretty close. Pin-outs are the same, just some subtle differences in the actual circuit. Cheers, Jonathan |
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Re: CS-80 tech question: initial velocity problem on TSB board
开云体育Hi Jonathan!Happy New Year and sorry about your CS80 problem. ?It sounds like you’re doing a good job trying to isolate the problem. ?However, I don’t know if you can do this with just a multimeter since the signals are multiplexed by the 4051. ?I think a cheap, used oscilloscope would really help. ?The fastest clock in the digital logic is only about 100KHz so even a 1Mhz or 10MHz. If IC4, pin 3 is really stuck at +15v, that ?would give you max velocity (initial touch) and aftertouch on those 6 notes. ?What if you remove IC4 and leave the socket empty? ?Is it still +15? ?That would indicate a short on the board. ?If not, then your idea of the op-amp, IC7 having a problem could be it. ?Try replacing/swapping/removing that. ?It’s just a common 4558 dual op-amp. ?If it’s not one of those or a board short, I’m not sure what’s going on. Good luck! ?David
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CS-80 tech question: initial velocity problem on TSB board
Hello,
I am looking for technical help for a Yamaha CS-80. The issue it is having is: a cluster of six notes (G2 to C3) generate full volume at all times when keyed, no matter how softly they are played. I have traced the problem to IC4 (a newer 4051 multiplexer) on the TSB circuit board, and have tested the chip with a multimeter. The INH pin 6 is not stuck high and is toggling as it should. Pin 3 (Com in/out), however, is stuck at +15V for some reason, and I can't seem to figure out why. I believe this voltage should be around 5V as initial velocity is triggered and approach 15V as the poly aftertouch is applied. I tried swapping in another 4051 from IC3, and the problem remains exclusive to the IC4 socket and the same cluster of keyboard notes. I've also checked the solder underneath for shorts and opens and compared it to the other 4051's on the board and haven't found anything out of the ordinary. Does anyone have any idea as to where I should look next? Could the IC7 (a JRC 072BD dual op-amp, also a recent replacement of the original 4558) that pin 3 goes to be involved? Could a faulty TKC board component be causing the problem? Any help would be greatly appreciated. Thanks! Cheers, Jonathan |
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Re: cannot seem to access CS80 group!
Murilo Faria
Thanks guys! Sorry about the mess! I don't use Yahoo Groups in a long time! Bests,
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Murilo Faria (Mura) |
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Re: cannot seem to access CS80 group!
Jonathan sent this mail to my mail-account directly. I answered him the following:
toggle quoted message
Show quoted text
-----------snip----------- Hello Jonathan I am not the moderator, but your posting appeared on the groups list. So appearently are subscribed and the address jw_dewdney@... is the valid address. The last postings were from Murilo Faria on november 21st. Do you read the group as maillist or do you read it online in the browser? Florian -----------snip----------- maybe the real group owner / admin can get in contact with him. Florian Am 01.12.2017 um 09:24 schrieb Jonathan Dewdney jw_dewdney@... [yamahacs80]:
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Re: cannot seem to access CS80 group!
Hello Jonathan
toggle quoted message
Show quoted text
I am not the moderator, but your posting appeared on the groups list. So appearently are subscribed and the address jw_dewdney@... is the valid address. The last postings were from Murilo Faria on november 21st. Do you read the group as maillist or do you read it online in the browser? Florian Am 01.12.2017 um 09:24 schrieb Jonathan Dewdney: Hi Florian - I think you are the moderator of the CS80 group? --
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cannot seem to access CS80 group!
Hi Florian - I think you are the moderator of the CS80 group?
Do you know anything about changes to Yahoo's programming that has been causing problems? I do not seem to be able to access the CS80 group - nor any other yahoo group i am a member of! Have you heard of this? Do you know if there's another way to access it (apart from the links in the e-mails)? I am using Firefox on an apple computer (since it became impossible for similar reasons to access yahoo groups on safari some time last year) thank you very much and sorry to bother you |
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