I have an old electric Hammond organ I recently restored and added a line out ect. But what I am attempting to do now is build a midi input circuit just like Sam did with his pipe organ . I basically have a lead soldered to all individual 61 keys on the key bus , and also have one -28 volt com wire , which when crossed with any of the 61 leads triggers the corresponding note to play. My understanding was that I could connect every key lead cable to the input terminals on the board like he did and the COM -28v cable to the V+ on the board that goes to the COM leg on the multiplexer chips ,hence when midi signal gets sent that makes the closed connection . The board is build and triggering midi input just fine , but when I connect the organ com and the input lead from a key it’s shorting the two together continuously.it’s pretty simple but the organ having that -28v com throws me off . It’s -28v constant and then when a key is pressed it goes to zero . I’ll post pictures here soon . Sam would be proud lol . If anybody has any suggestions it would be much appreciated this organ has been a passion project for a few week now and I can’t wait to get it midi’d out .
