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On eBay I had bought parts of a Casio Symphonytron. I don't own the entire stage organ system but only one CT-8000, the RC-1 accompaniment/drum machine and a defective MB-1 sequencer in very beaten up condition (full of scratches, dirt and glue residues), but no pedal board. It came without the CIDI (Casio's Infernal/Inferior/Internal/Instrument Digital Interface) cables, so I ordered 3 DIN14 cables for Atari ST floppy, those work perfectly with the RC-1 (with one keyboard it does key split accompaniment with arpeggio, and also the trio mode works). Like with Kawai MS20, when you set a preset sound on the keyboard it plays a short fanfare with it (always the same notes). How ever my MB-1 doesn't work at all (buttons don't respond and it makes sometimes a louder growing digital buzz); possibly the eprom is dead. Also CT-8000 and RC-1 contain (as the only Casio instruments I know) each a soldered eprom; I backed up all 3 to avoid data loss. Unfortunately my Symphonytron sequencer unit MB-1 is dead (does nothing, but plays note mess when touching the crystal etc.), so I am not sure if its eprom may have failed (dump does not change by reducing Vcc) or it might be still a bug by the lack of original CIDI port cables. - hardware details I have photographed all my Symphonytron PCBs from both sides. The multi-chip hardware is quite complex and particularly the RC-1 and MB-1 have several stacked PCBs in their crowded case. Fortunately there are are some pinout marks on them, those may help to decipher them. The MB-1 and CT-8000 both have the same CPU "NEC D8049C 364" (Intel MCS-48, I dumped its firmware) with sound IC "D931C 011". The RC-1 CPU is a "NEC D930G 011". So they are far relatives of the Casio CT-410V (MT-65) hardware class (minus the VCA, but with external ROM) which may help to research hidden functions of its chip set. I don't own the FK-1 pedal board, so I have no clue what is inside. Did you know that early Casio keyboards had a CPU compatible with Intel 8049? Unfortunately the "Willem Pro4 isp" eprommer had a way too weak power supply with tiny SMD transistors switching the voltages. One was burnt anyway, so I had to install bigger non-SMD ones to get the MCS-48 adapter to work. Casio "D8049C xxx" ICs need Vcc of at least 4.5V to read properly, which was impossible with the original transistors ans PSU (it gave only 4V even in 5.6V mode). I installed a 10kOhm resistor into the EA line to avoid damage by the +12V if the IC would not have supported it properly, and connected it to a 5kOhm potentiometer to vary the voltage, which I didn't need. (Too high EA voltage (15V) outputs only "00" while too low voltage (9V?) makes the CPU run its program and output garbage. At too low Vcc it repeats the first part of the rom again and again.) So I e.g. could read the firmware of the Symphonytron Casio CT-8000 cpu and Casio HT-6000 synth (its D80C48 seems to be a real CMOS IC that draws less current). Also MT-36,MT-40,MT-90/MT-200 and Casiotone 401 have such a CPU. - need service manual Eons ago I downloaded the complete Symphonytron user manual from an eBay link, but I have no schematics. Has anybody a service manual? Particularly I am interested in the MB-1 hardware, the official CIDI cable wiring (may the MB-1 only need a crossed wire somewhere?) and the pedal board (has anybody dumped the eprom?).
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I have many electronic keyboards. 4 of them are Casio Arranger keyboards. Until now they have been pretty much bullet proof. The WK6500 has a high G key that plays only full velocity and does not return to full height after playing. I am fairly sure that the pad under the key is bad. How can I repair this? And where can I buy the part? Or do I just chuck it and buy another instrument?
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Hello, I am collector of music keyboards and electronic sound toys and partly modify them into synthesizers. This is my keyboard site: http://weltenschule.de/TableHooters/index.html I bought an eprommer ("Willem PRO4 isp",had unfortunately defective transistors and other flaws I had to fix) and have started to dump EPROMs and ROMs of my keyboard collection. - Has anybody tried yet to make an emulator (similar like MAME) for old Casio keyboards? E.g. Casiotone 401 and MT-40 are controlled by an Intel MCS-48 microcontroller which ROM I successfully dumped. So at least the accompaniment section would be possible to emulate yet. Robin Whittle (firstpr.com) found out much about the Consonant-Vowel synthesis main voice sound ICs in early Casios, which would be useful to emulate them. Also the various Casio calculator emulators on the internet might be useful to understand what kinds of special CPUs Casio has used. Google patent search helped much to get an idea what is going on inside of them. Unfortunately most early main ICs seem to be rather based on general digital logics (networks of gates, counters and flipflops - like a Pong game) than a CPU (software controlled by one central code ROM) in its stricter sense. I am still working on documenting the pinouts and functions (e.g. key matrix eastereggs) of all 1980th Casio home keyboard special ICs. For this I already have examined all service manuals I could find on free websites. Unfortunately there aren't many about first generation Casios. (If you need info, e-mail me.) I also own a dead SK-200 (from eBay,someone elses circuit-bending-corpse); after disabling the auto-power-off (to make it turn on),only all lights flicker wildly and there is some bus activity (seen on CRT oscilloscope), but it makes no sound at all. Does anybody know the symptom? Is the sound CPU dead?
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