Its an replica - not just another clone
Schematics and Service Notes:
BOM: (last upload 08/2021)
|1||Wiring||You can use the MTA100 system from TE connectivity for example -|
|2||noisy/hiss||make sure to solder the potentiometer at all pins to have the correct ground - (the ground flow thru the outside pins / it act like a trace/bridge)|
measure the transistor HFE value for the switchboard Q604 - a gain of 350 should be fine.
otherwise it can happen that MIDI OUT doesn't work.
you can also mod the MIDI Out : http://www.colinfraser.com/tr909/909mods/909midi.htm
select the * S* Transistors to the same HFE to get a balanced gain on all voices.
check the schematics for more details:
q12 in Bassdrum
q51 in snaredrum
q20 in Low Tom
q27 in Mid Tom
q58 in High Tom
Q71 in Crash
Q85 in HH
Q65 in Rimshot
Q37 in Handclap
Q33 Tom Noise - should be ignored or just use the same hfe as above