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Clean CS-80 Overall Circuit Diagram

unfrostedpoptart All Messages By This Member #4354 Forgot to mention - I really like the job you did on the diagram! ? ?David
Joachim Milson All Messages By This Member #4355 Hi David, Of course I'm aware of the two sites you mention. I have browsed them both more than once. Without them, my project would certainly not be well under way as it is today. I want to share my reworked CS-80's overall circuit diagram with the people interested in studying it. The original printed version has so many errors (just to mention drawing errors or oversights), I can't count them. I fixed most of them with the diagrams of the service manual and the circuit boards. Working on the interactive diagram for the site, lately, I still found a few errors (less important, but errors anyway). Sometimes, the layout is unduly complex (but all was hand-drawn then). I try to make it more immediately understandable. I just uploaded the interactive diagram. For the moment, only one third is interactive (the left part). I hope it will be of some help for newcomers who wish to understand the inner working of the beast. Joachim
noddyspuncture All Messages By This Member #4495 Hi folks, Currently I am looking at the 'M' boards in one of my CS80's with view to recapping and?I had a look at the circuit diagram to cross ref against what I see on the board. On the board I see 4x 100uF capacitors... yet the schematic only shows 2 (near the IG00153). I cannot find the single 33uF cap on the board which is shown near the VCA/IC1 on the schematic. I am assuming that they fitted a 100uF there - which still leaves one of the 100uF caps unaccounted for..! I also see 4x 4.7uF polarised caps on the board... yet the schematic shows only 2 (across the power rails next to each IG00156) There also seems to be 4.7uF anomaly though... the polarised ones are 50v rated whereas the non-polarised ones are 16v rated on the schematic. Also on the schematic, non-polarised 4.7uF are marked 'NP' but the one near the IG00153 shows as 16v but doesn't make any reference to polarisation..! So the question is which are these other 4.7uF polarised caps...? I think the schematic needs updating here as well..!? Cheers, Tom
Joachim Milson All Messages By This Member #4496 Hi Tom, Thanks for pointing these issues. You're right concerning the 100uF capacitors. There are 4 decoupling capacitors; two between ground and +15V, and two between ground and -15V. I changed the 33uF one near the IC1 to a 100uF, and I added a new 100uF one near the IC3 (which corresponds roughly to where it really lies on the board). As for the 4.7uF capacitors, those on my boards are in compliance with the schematics. Two are polarized and are yet other decoupling capacitors (between -15V and +15V, this time). The other two are non polarized and are located near IC8 and IC9. I updated the overall circuit diagram to reflect these. It is available . I also put in the photo gallery of the CS80 group a copy of the M-board schematic (p44 of the service manual) where I highlighted the 42 capacitors, and also fixed a couple of missing components and a label inversion (fixed in red). You can find it . Joachim
unfrostedpoptart All Messages By This Member #4497 开云体育 Speaking of replacing caps. ?For years, I’ve replaced tantalums whenever working on old gear because of their problems like exploding. ?There’s one-per-note on the TSB boards. ?I just read in ?that there’s another important reason: I had no idea they were connected with conflict minerals! And I also didn’t realized what this did to the price when companies switched to non-conflict sources a few years ago: ?David toggle quoted message Show quoted text On Jan 8, 2017, at 9:17 AM, joachim.milson@... [yamahacs80] <yamahacs80@...> wrote: Hi Tom, Thanks for pointing these issues. You're right concerning the 100uF capacitors. There are 4 decoupling capacitors; two between ground and +15V, and two between ground and -15V. I changed the 33uF one near the IC1 to a 100uF, and I added a new 100uF one near the IC3 (which corresponds roughly to where it really lies on the board). As for the 4.7uF capacitors, those on my boards are in compliance with the schematics. Two are polarized and are yet other decoupling capacitors (between -15V and +15V, this time). The other two are non polarized and are located near IC8 and IC9. I updated the overall circuit diagram to reflect these. It is available?. I also put in the photo gallery of the CS80 group a copy of the M-board schematic (p44 of the service manual) where I highlighted the 42 capacitors, and also fixed a couple of missing components and a label inversion (fixed in red). You can find it?. Joachim?
Tommy Priakos All Messages By This Member #4498 开云体育 Whoa! That is incredible background info. So if we've never replaced those caps, would our?CS-80s have these minerals of conflict? If so, it would be my only keyboard that has a scandalous reputation, ha!? Well, I have no background history on it when Roy Orbison owned it, Who knows the things that might've gone on around it when he had it in his studio! toggle quoted message Show quoted text On Jan 9, 2017, at 7:13 PM, David Rogoff david@... [yamahacs80] <yamahacs80@...> wrote: ? Speaking of replacing caps. ?For years, I’ve replaced tantalums whenever working on old gear because of their problems like exploding. ?There’s one-per-note on the TSB boards. ?I just read in ?that there’s another important reason: I had no idea they were connected with conflict minerals! And I also didn’t realized what this did to the price when companies switched to non-conflict sources a few years ago: ?David On Jan 8, 2017, at 9:17 AM, joachim.milson@... [yamahacs80] <yamahacs80@...> wrote: Hi Tom, Thanks for pointing these issues. You're right concerning the 100uF capacitors. There are 4 decoupling capacitors; two between ground and +15V, and two between ground and -15V. I changed the 33uF one near the IC1 to a 100uF, and I added a new 100uF one near the IC3 (which corresponds roughly to where it really lies on the board). As for the 4.7uF capacitors, those on my boards are in compliance with the schematics. Two are polarized and are yet other decoupling capacitors (between -15V and +15V, this time). The other two are non polarized and are located near IC8 and IC9. I updated the overall circuit diagram to reflect these. It is available?. I also put in the photo gallery of the CS80 group a copy of the M-board schematic (p44 of the service manual) where I highlighted the 42 capacitors, and also fixed a couple of missing components and a label inversion (fixed in red). You can find it?. Joachim?

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