Kawai SX-240 -1983    Weight=28.5 Lbs Number mfg.= 1000 MRP= $1695

User Manual: Kawai US or Synthmania
Reset Proceedures: N/A
Operating System code:
MIDI or other control protocol: See Manual
Software related Links:
Patches or knob settings: synthmania
Circuit Overview: below
Scematics/Service Manual: My pdf! (Please send 2 dollars to help defray the hours that went into these 45 pages; many that required stitching together, to the sounddoctorin@gmail.com via paypal) or Manual Manor for hard copy
Common Service Issues/Tips: below
Parts Sources: Keys semiconductors misc
Uncommon chips/modules used:8253 pgm. timers, SSM2044 VCF, BA6110 ota's, MN3009 BBD's, 2- 8031 cpu's, .3" 6116 SRAM
General Info Links: Vintage Synth Explorer

Circuit Overview:
     Two DCO/voice version of SX-210 in many respects. They use 8253 programmable timers for DCO's and two CPU's to control the various facilities. Subtractive with digital controlled/generated oscillators and dial/button select data entry.

Service Tips:
      Bad solder galore in the one I worked on. The battery is likely to spill caustic stuff. They placed these better than in some machines but STILL things can get damaged so watch out!
More recently one had a power supply problem that let 5V hit 7.5V or so. The CPU apparently was damaged as after I replaced the buzzer stayed on all the time instead of intermittently. The last problem though was line SAD6 being clamped in some way by the .3" 6116 chip by the slave EPROM. Just have to cut traces and patch them back in such instances to confirm what is causing the problem since they aren't socketed except EPROM on that one.


I should have many parts for these. Contact me if you need something.