via this auction
"This is a midi kit for your Roland TB-303... Here is a link for the instructions MB303"
EVERYTHING SYNTH

Here is an unrepeatable opportunity to commission a custom rebuild featuring all of Graham Hinton’s Modifications and more built into either rack mounting format or portable in a Zero instrument case. We have an original Sealectro 16×16 matrix or could expand it to a 20×20 Ghielmetti matrix, fully buffered of course. All pots would be conductive plastic with Elma collet knobs. This could be the synthesizer that EMS never built, but should have."