How do you know the circuitry in the keyboard is any good?
Is the 9 pin connector supposed to get power and ground on 2 of those?
Can you find any docs on the keyboard circuitry? Does it read the keys, hammers or strings?
Well the thing is I don't know, and I'm hoping it works.
I don't know that either, is it risky that I try to send 5V + ground to all possible combinations of cable on this?
Nah I couldn't find anything, it's old and it wasn't a good piano when it was released...
Were you trying to ohm the contacts with the DVM set to volts?
Nope I pu the DVM on ohm, I just wasn't sure on how to call it (I'm French).
I was thinking that an "old piano" would be made of wood and ivory and you were thinking of putting a switch under each key.
If MIDI is broken then the problem could easily be anywhere inside the box. That will probably disable the other outputs too. You would be extremely lucky if it was only the MIDI connector that's broken.
If MIDI is broken and you want to use MIDI, then try to repair any failed components that you feel competent to repair. If it's still broken, then buy a new one. We're not talking about something that's actually expensive are we?
By old piano I meant old numerical piano. And putting a switch under each key would be doable but I'm not sure on how to get nice velocity from that :/
It's not just the midi, the transformer got cooked and the circuit got fried too, it was like this :
Transformer (with multiple outs, big transformer, don't remember de values) ==> Power Amp ==> Motherboard (with keyboard connections and midi in & out) ==>Control board (with a few buttons to control the original sounds that I wasn't going to use anyway).
I'm just left with a keyboard with the addr and data cables connected to it.
How did you make that measurement? If you used a voltmeter, was the keyboard connected to anything (the old circuit)?
I took my voltmeter, set it to ohm and connected it to the first and last connections of the cables. Tried both cables, and multiple cable combinations on them.
A little bit more info on the piano :
I got it for 20 bucks from my High School when I was a student there, it was already old and had problems too. I took it home, I cleaned it, tested it, removed parts, cleaned them, put them back and It worked, one day the transformer took the power out in the house and smelled like bacon, the piano was done, but I recovered the keyboard.