The Roland Sound Canvas (SC-155) is a desktop (aftertouch and velocity sensitive), 24 voice (multimbral), GS/GM compatible digital synthesizer, featuring a resonant low-pass filter, an ADR envelope, vibrato (with delay), portamento, reverb/chorus, 128 presets, 10 drum sets, stereo mix inputs, and MIDI.
Early January 2024, a cool Craiglist local advertisement for a 50€ Roland Sc-155 in quite perfect shape in the zone of Naviglio in Milano. That was a perfect occasion to collect it and have a nice pizza with my partner in a windy cold, but sunny day. Afterwards we could not miss some delicious cakes and an hot expresso at the "Fugazzi's pastry bar", owned by a 90 years old lady with full sweet smile.
Back home with the SC155 (and one more Kilogram) it was time to put it on the bench and fire the module up, but before ...
Forewords: OK , I do love analog vintage synthesizers, but for some obscure, insane, Freudian, psychopath reasons, I do also appreciate Sound canvas and old GS-GM stuff. Maybe because I started making music with a 486 DX33 with a Soundblaster AWE32 and a Waveblaster canvas for some dull, fake flat sounds. Today I have quite a several bunch of half racks from Roland, like the famous Sc-55 ( "rare" version MK2) and of course the father of all: the MT32 with infamous Linear L.A synthesis.
First test with classic DOOM and ULTIMA Midi files, some all-time favorites. Ok sliders potentiometers ok, sound ok (F**K HATE CINCH RCA!) headphones. The only, classic, issues are some of the buttons the most used, both instruments "+" and "-" that change the sound patch of one of the 16 parts.
The tact switches are usually corroded by time or too many finger pressures. It had exactly the same trouble with another SC-155 (ok I admit, I have two now but keep it for you) but this time I will write some notes of what I did for future repair.
Ok let's grab the loyale screwdriver and open the case.
UPPER - As you can see there are 2 series of 3 screws under the hood, do not mix them and remember the type used.
UPPER You must detach all flats to access the button matrix. Do not force and do not bend any pins! You don't have to write down the flat's location, since all of them have a specific length and number of pins on the JT connector. Btw, while you're here, it won't be a bad idea to change the 3V battery, it's not soldered like Yamaha fanboys.
UPPER once you removed the two parts, there 's 3 more screws on a metal rail that holds an insulating silver sheet. Finally remove 4 little screws in the upper left corner. The board will come out easily (pay attention not to lose the plastic caps "ALL" and "MUTE" under the special diode-emitting Led tact switch). Locate the two tact switches (or change 'em all if you want a hell of a job!) and just unsolder and replace with 2-legs replacement - less common than standard and more stable 4 legged pins.
Well, it's nice to change freely between pizagogo and banjo patch with jumping on the button with an elephant. Not to mention the all mighty tr808 drum kit - Now it's time to play!
"TA DA TA TA DA TAAA TAA TAAA"
If you need it, here's the english MANUAL
and here the SERVICE MANUAL
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