mistercooper
New member
Hi everyone,
first time posting in years... I've acquired a both a Yamaha CS-60 and CS-50 that need some work. The 50 is already mostly operational save for a couple envelopes. The 60 is in need of more attention, but I would rather get this one going as it has twice the voices and an awesome ribbon controller. If you've got any experience with this series of synths you know they're in many ways like working on a car... tens of boards littered with proprietary parts. I will use this thread to document my progress working on these machines and to put my questions in one place. Please feel free to chime in if you have any ideas or questions.
Anyhow, the first issue I've run into on the 60 is actually kind of mundane. Not getting proper voltage from the +-15 rails. My problem is that when the PSU is attached to the circuit, I can't know if there is a short on a board somewhere down the line bringing down the supply, but if I detach it and short the +15<->+15s and -15<->-15s, (I assume to maintain a load on the supply so it can operate) I get only a couple milivolts on the pins. Attached to the voice circuits, the PSU is somewhere around +.9v and ground-ish on the - rail. Any ideas why I can't test it with the boards disconnected from the psu, but it generates a volt when the cards are attached?
I can easily make measurements/scope anywhere in the schematic and report back if you have an inkling what might be going on.
Here is a copy of the relevant page from the service manual:
http://therogoffs.com/cs80/manuals/CS60_Service_Manual/29%20-%20SVU%20Circuit%20Diagram%20&%20Circuit%20Board.jpg
Thanks a bunch,
Cooper
first time posting in years... I've acquired a both a Yamaha CS-60 and CS-50 that need some work. The 50 is already mostly operational save for a couple envelopes. The 60 is in need of more attention, but I would rather get this one going as it has twice the voices and an awesome ribbon controller. If you've got any experience with this series of synths you know they're in many ways like working on a car... tens of boards littered with proprietary parts. I will use this thread to document my progress working on these machines and to put my questions in one place. Please feel free to chime in if you have any ideas or questions.
Anyhow, the first issue I've run into on the 60 is actually kind of mundane. Not getting proper voltage from the +-15 rails. My problem is that when the PSU is attached to the circuit, I can't know if there is a short on a board somewhere down the line bringing down the supply, but if I detach it and short the +15<->+15s and -15<->-15s, (I assume to maintain a load on the supply so it can operate) I get only a couple milivolts on the pins. Attached to the voice circuits, the PSU is somewhere around +.9v and ground-ish on the - rail. Any ideas why I can't test it with the boards disconnected from the psu, but it generates a volt when the cards are attached?
I can easily make measurements/scope anywhere in the schematic and report back if you have an inkling what might be going on.
Here is a copy of the relevant page from the service manual:
http://therogoffs.com/cs80/manuals/CS60_Service_Manual/29%20-%20SVU%20Circuit%20Diagram%20&%20Circuit%20Board.jpg
Thanks a bunch,
Cooper