A computer that works some math on samples and has a nice analog chorus on board also. :-) Uses the serial dac common to S-10 and others of the series.
Other than key cleanings and some dirty buttons I haven't seen much trouble with these machines. Loading patches from MIDI CAN be a real problem though. On both a D-550 and D-50 recently with version 2.10 EPROM I had horrible problems. (Hold '0' on keypad and 'increment' while turning on power to get the version number! Boomer said it had to do with Yamaha hassling them about copying their way of doing things or something. Anyway here's the proceedure that worked for me. We're just using a cable from 'out' to 'in' on the D50. No handshaking.
1) Turn off memory protect (under tune/function, select memory protect with buttons underneath display then 'decrement')
2) Set MIDI channel to 1 under midi
3) hit 'Data transfer' once.
4) NOW hit 'Data Transfer" at the SAME TIME as you hit the soft key for 'B.Load' DO NOT RELEASE 'Data Tranfer'!
5) Not while still holding (don't release 'Data Transfer' til the patches are totally loaded!) hit 'Enter'
6) Begin your transfer from whatever you are using to load the sounds. After several seconds 'transferring' shows up on display. And eventually 'Completed'. That's it hopefully!
I have a few of the slider caps I believe. Contact below..
Roland still stocks many parts for older instruments! You can always order them through your local Service Center and see what happens! Otherwise I have some parts also so don't hesitate to ask. WE HAVE A SCRAP UNIT right now but some things are gone I think on it.
Contact Sound Doctorin'