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via
this auction
via the listing:
"It has had the red LEDs replaced with blue ones, the switches have been replaced and are working flawlessly (no double hits making programming impossible) and has been recently serviced by a well known tech who specializes in TB-303 maintenance/repairs. The previous owner had installed a CV mod on it, hence the CV holes in the case. I had the tech remove the mod (it didn’t work) and restore it to its original condition as well as get it serviced to Roland manufacturing specs."