Circuit Overview:
Sounds from the K250 largely, using 7x oversampling and floating point to gain more sonic depth. Purely Digital with specialized chips with "arnold" on labels that perform the 'engine' work. It's good to note that the original K1000 lacked after touch but the "SE" version added that. Also the PX, HX, SX, GX, expander modules were available to add pro, horn, string and guitar sounds in separate racks. SX and PX were combine to make "AX" acoustic expander eventually. And an internal expansion was available for each also I believe. But anyway eventually the K1000 SE II units came out with version 5 EPROM and they supported the more advanced controller features found in the later pro 76 and K1200 which contained the K/PXB ROM sound expansion. THe K1200 just added more keys and user RAM over the pro 76 from what I can find.
Service Tips:
"Arnold" chips have been known to have socket problems. Earlier black sockets replaced with brown ones. I recently worked on one where someone bent the pins and that led to some real interesting delay effects. Bizarre. I could probably put a switch in to recreate it and sell it as a 'circuit bent' thing on ebay :-).
Parts:
Kevin Lightner (Synthfool) has Arnold chips. I have a lot of the other parts for these including a pot and knobs that are close enough but not exact. I believe. Round the edges :-).
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