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another "MIDI does not work" post? ;)


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Guys, sorry that I post this quite general 'MIDI does not work' topic, but with the thousands of results you get when searching 'midi problem', 'optocoupler' etc. I couldn't find if this issue happened before or if I overlooked something.

History:

- tried to USBify MBSEQ V 3.4f using a single GM5 module.

- the GM5 module worked fine when connected to PC (before having any connections to the SEQ).

- after connecting MIDI in/out to SEQ's Core v3 via J11 ("MIDI IO at TTL level") , the GM5 didn't work. (its status LED shone veeeeeery dark, looked like a typical short circuit)

- while GM5 was connected, SEQ had hickups when I pressed play, later showed a message something like 'MIDI timeout' or so.

- removed GM5 again, decided to stick to the regular external USB-MIDI interface, re-connected original MIDI in/out connections of the SEQ.

- I realized I had an Optocoupler both on the GM5 and on the Core.

Symptoms:

- SEQ works, but no MIDI in/out at all now. (doesn't send any MIDI out, nor does it receive/react to MIDI in) Different PIC was tested, MIDI wires were replaced, Optocoupler was replaced.

- If it's a firmware problem, I seem to have no way to re-upload mios or the application unless I upload via a second Core.

Does anybody have a suggestion what could help?

Thanks!

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ok have you pulled the optocoupler in ic2? if not pull that you dont need it

also have you linked the gnd pin from the gm5 to the core? this is will give you a timeout error also.

also make sure you have the pins linked correctly, use J6 on the gm5 for midi in and out to the core and use the gnd from J7 to link the gnd from the gm5 to the core gnd.

as in this picture.

gm5.jpg

once you have it connected like that, load up mios, connect the relevent links in the midi setup and then try reuploading mios first, then reinstall the seq files.

Edited by ssp
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Thanks for the reply!

I indeed didn't ground the GM5 module via the Core, cause I assumed it's already grounded via USB (since the power supply comes from USB) So probably the GM5 module got damaged that way.

But my GM5 seems broken anyway, so...

What I am trying now is to get back my regular MIDI connections via the Core's J12 and J13 ports. To make it clear, they are broken now for some mysterious reason, despite a different pic, with different optocouplers and different MIDI wires. Do I have to replace the whole Core now? How come? Could the diode on the Core have been damaged? test (although i tested the diode with a multimeter as well...)

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just connect the gm5 on its own, see if thats working and being picked up in the operating system. make sure the gm5 has its optocoupler in, as that will need it. also on the ucapps site is a driver for the gm5 grab that just in case you need it, dont write the gm5 off just yet.

as for the core you have changed components etc so first thing first check all of your connections, check for shorts and solder joins etc.

pull the pic and then check the voltages as per the instructions on ucapps.de.

check things one by one before ruling them out.

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just connect the gm5 on its own, see if thats working and being picked up in the operating system. make sure the gm5 has its optocoupler in, as that will need it. also on the ucapps site is a driver for the gm5 grab that just in case you need it, dont write the gm5 off just yet.

Thanks! Just have to check my Core and GM5 --- again and again! :)

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Solved!

The solution, just to conclude this thread:

The problem was a combination of all those little things.

The GM5's status LED seems to be broken and possibly caused some weird quasi-short circuit (?)

The original pair or midi connectors didn't work for a reason, a newly soldered pair didn't work for a reason, a third newly soldered pair finally worked!

My stupid Macbook's USB ports are too weak, both for the GM5 module and for my cheap Swissonic MIDI interface! No wonder I had no MIDI traffic at all.

I have to connect a powered hub inbetween -- now both work fine.

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