“For sale is a vintage Yamaha CS40M duophonic analog synthesizer in very good working condition. This rare synth can lock in a wide variety of awesome tones, from nasty bass to screamin’ leads and many places in between! It features a versatile control panel, rock solid Japanese build quality, and a supremely retro look and feel. This beautiful machine is something very special indeed! A great addition to any studio or player looking to expand their vintage synth collection.
This instrument has been thoroughly serviced by a professional technician and is backed by our CV Keyboards 3-month warranty. It’s in very nice shape for its age, with some scuffs and other normal cosmetic signs of use throughout (see photos). Does not include stand or other accessories.” Click here to visit listing on eBay
“In very good condition! The unit has been thoroughly tested by our professional technician and works perfectly. Please see post for details.” 
” This 1970s Yamaha CS-40M Analog Duophonic Synthesizer is in great shape and working condition. The CS-40m is a duophonic (2-voice) analog synthesizer! It was recently serviced in January 2019 to repair a broken trace in VCO 1 and reconstruct/remount broken PC boards. ”