maxx11

looks like it might be a bad uln2803, new ones on order

I have a core and 2 DOUT modules to midify a band organ. When the core is powered up midi note 45 is always on ( LED shows 1|note C_2 Oo) With no midi input connected to the core the note is on, if I connect my midi file player and play a tune it will play all notes just fine BUT midi 45 will always be on. Any suggestions please? I'm stumped.

Thanks Tim for the clarification on the DOUT board. Wellll I connected the ULNs to ground and +12 common ( pins 9 & 10 ) and DOUT Vs to ground. All pipes play BUT there are always 2 that don't,always different ones. At first group 7 D4 and D7 were dead. Tested with LED's and reconnected and they worked,but then group 6 D6 and D7 were dead. Checked with LED's, reconnected and they worked but 2 others were out. Maybe it's a software bug and I need to reload? Occasionally a note will not turn off when hitting stop. A pause command will usually do it. Don't know if it is midio or my player. Will have to hook up my LCD to the core and see if I can see anything. Any suggestions? Thanks!

Thanks Lyle, was going to try this today but got more confused, using a DOUT board from smashtv but don't see any connections for pins 9 and 10 of the uln which is mounted on the board. There is a Vs pin on the J3-6 output connectors but I read .7 volts between this pin and power supply ground. Is it ok to tie the Vs pins from J3-6 to supply ground? Thanks for your help!

More info: core 8 with 18F452 PIC,ULN's mounted on DOUT board, relays and core powered separately from a 12 volt motorcycle battery, relays are 90 ohm 133ma at 12 volts,each relay has a flyback diode and series diode to isolate 2 ranks. Tried a couple of things: moved the outputs of DOUT group 3 01,02,04 05 that didn't work to group 4 01,02,04 05 and sent each a midi signal separately and they worked, tried again and they didn't work. Some,but not all, of the outputs feed 2 relays each with a separate +12 common buss. For now these are tied together, I will see what happens if I remove one, but since some of the outputs that don't work only feed 1 relay I can't see that it would make a difference. Thanks for your help.

I am building a band organ with a core and 2 DOUT modules feeding relays thru uln2803a's. The midi in is fed from a palm vx running ittymidi software. When first tested with a song not all notes played.I have a midi file where you can play each note separately and found 10 midi channels not firing(out of 64). I disconnected everything and hung LED's on the DOUT outputs. When I send a midi note signal from the player,the respective LED lights for each channel, so this should be telling me that everything is working correctly? I have a LCD connected to the core and when I send a note (say C) the LCD shows note C. So I hook everything back up and send single note commands to the organ relays as I did with the LED's,only again I have 10 or 12 channels not firing,some the same as not firing previously, some different. I hook the LED's back up to the channels that are not firing and they light right up. Any suggestions? I am totally confused. One other issue is that the LED's sometimes don't turn off when I hit stop but I think that my player is not always sending a note off command. Appreciate any help you can give me. Thanks.