Holy crap, this amazing! This must be the one Tommy Mars played when he was in the band. You can see (and hear) it in action in the Halloween 1981 concert video. Tommy primarily used this for a brass pad type sound, but he had a great string sound on it as well. Any chance those custom patches are still intact?
His memory presets are still intact on both machines. I’ll have to check that video out to see which one of the two he was playing and if the presets match. This was the least modified and most complete of the 2 keyboards. The pitch wheel modded synth will be rebuilt in the future and I plan on keeping his pitch wheels in place and functional. Going to patch the pitch wheel into the pitch ribbon circuit so both controls work. That’s the plan anyways.
HELP! Service manual has invalid data regarding filter calibration on the voice cards. Anybody reading this ever calibrated CS-80 filters using the service manual instead of resorting to listening by ear and “close enough”? Anybody have Deckards Dream schematics? Perhaps from there I can reverse engineer the correct filter range.
Check this blog: mfoxhd.blogspot.com/2015/12/yamaha-cs-80-calibration-intro.html On that website there is all the information for the CS80's calibration, and the author talks about the wrong service manual instructions too, specifying what are the correct values for the wrong ones in the documentation. Here also you may find useful information for the CS80: joachim.milson.free.fr/
LEDs are to indicate what card is active for calibration, otherwise there is no way to know other than electrical testing the control lines every time. I only came across 2 bad chips. One filter and one Hitachi stereo preamp. Everything's else was good. The chips seem to be very durable. They made it 40 years, should make it another 40. No FLASH or windowed EPROM memory to go bad. The controller is either ASIC or some type of mask programmed device, so nothing to become corrupt. Only the 4000 series cmos get flaky, but that was the fabrication process of that era and those are still available and replaced.
The white noise generator preamp stage, IC1 on the SUB oscillator board. It's the dual 4558 op amp right after the zener diode circuit that creates the actual noise itself. The 2nd dual 4558 unity-gain op amp (IC 3) after the two VCA chips in the noise generator does not have to be changed. That one is operating within specifications no problem. The gain on the original 3MHz bandwidth amp was way too high as they tried to compensate for the poor bandwidth, so all the noise above 3kHz is distorted. I tried at first a 10MHz bandwidth audio grade op amp, but it still had slew artifacts. Tried Excalibur and finally clean waveforms on the scope. No more strange slew distorted waveforms and muffled white noise as you go to higher pitched notes. The gain on the old op amp was maxed out beyond proper parameters, so you will have to recalibrate the white noise section voltage output to 2 volts as in the service manual. The Excalibur has significantly more output not having slew rate limited output of the older, less efficient chip. Be aware this will change the white noise sound characteristic of the CS-80.... that is real white noise now. So socket the chip in case you don't like it to put the old one back. But I am certain this was a design oversight as there were design changes from early to later models trying to eek out more bandwidth. They should have added one additional stage of preamp as the conventional op amps didn't have the gain bandwidth at the time. Sorry for the long response.
It's so moving to hear it 'cry' again.
Good job-bring back Frank while you're at it
oh wow this is actually nuts
Number 701, one of the last in the series.
Thanks to Frank.
This seems to be the best CS80 restoration I've ever seen. Fantastic!!
I hate how rare these are. I just want to play one, but never will in my life time. Sucks.
Happy rebirth babe!!!
Much respect to you who have the genius to be able to repair it!
no way 💙
Holy crap, this amazing! This must be the one Tommy Mars played when he was in the band. You can see (and hear) it in action in the Halloween 1981 concert video. Tommy primarily used this for a brass pad type sound, but he had a great string sound on it as well. Any chance those custom patches are still intact?
His memory presets are still intact on both machines. I’ll have to check that video out to see which one of the two he was playing and if the presets match. This was the least modified and most complete of the 2 keyboards. The pitch wheel modded synth will be rebuilt in the future and I plan on keeping his pitch wheels in place and functional. Going to patch the pitch wheel into the pitch ribbon circuit so both controls work. That’s the plan anyways.
Frank Zappa the famous pianist !!!!
Dude, amazing!
Oh wow, you're the one who won the auction against me! :) I'm glad it was you!
HELP! Service manual has invalid data regarding filter calibration on the voice cards. Anybody reading this ever calibrated CS-80 filters using the service manual instead of resorting to listening by ear and “close enough”? Anybody have Deckards Dream schematics? Perhaps from there I can reverse engineer the correct filter range.
Check this blog: mfoxhd.blogspot.com/2015/12/yamaha-cs-80-calibration-intro.html
On that website there is all the information for the CS80's calibration, and the author talks about the wrong service manual instructions too, specifying what are the correct values for the wrong ones in the documentation.
Here also you may find useful information for the CS80: joachim.milson.free.fr/
I’d buy that for a Dollar
@@mima85 Long delay in this reply from me...THANK YOU! THANK YOU!!!!!!!!!!!!!!!
@@gavincurtis You're welcome, don't worry for the delay. Glad I was of help :-)
Bravo
Did you buy that for a dollar?
What use are those LEDs? So you can see which voice card is energized? How long do the custom Yamaha ICs last?
LEDs are to indicate what card is active for calibration, otherwise there is no way to know other than electrical testing the control lines every time. I only came across 2 bad chips. One filter and one Hitachi stereo preamp. Everything's else was good. The chips seem to be very durable. They made it 40 years, should make it another 40. No FLASH or windowed EPROM memory to go bad. The controller is either ASIC or some type of mask programmed device, so nothing to become corrupt. Only the 4000 series cmos get flaky, but that was the fabrication process of that era and those are still available and replaced.
I’d buy that for a Dollar
Hi. which op amp has replaced with excalibur?
Thanks
The white noise generator preamp stage, IC1 on the SUB oscillator board. It's the dual 4558 op amp right after the zener diode circuit that creates the actual noise itself. The 2nd dual 4558 unity-gain op amp (IC 3) after the two VCA chips in the noise generator does not have to be changed. That one is operating within specifications no problem. The gain on the original 3MHz bandwidth amp was way too high as they tried to compensate for the poor bandwidth, so all the noise above 3kHz is distorted. I tried at first a 10MHz bandwidth audio grade op amp, but it still had slew artifacts. Tried Excalibur and finally clean waveforms on the scope. No more strange slew distorted waveforms and muffled white noise as you go to higher pitched notes. The gain on the old op amp was maxed out beyond proper parameters, so you will have to recalibrate the white noise section voltage output to 2 volts as in the service manual. The Excalibur has significantly more output not having slew rate limited output of the older, less efficient chip. Be aware this will change the white noise sound characteristic of the CS-80.... that is real white noise now. So socket the chip in case you don't like it to put the old one back. But I am certain this was a design oversight as there were design changes from early to later models trying to eek out more bandwidth. They should have added one additional stage of preamp as the conventional op amps didn't have the gain bandwidth at the time. Sorry for the long response.
Thanks a lot !!