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I still can't get it to recieve MIDI, i took some pics of the board (poor qulaity i need to get a good camera ad repost asap) Front Back i tried the loopback test again and it failed, when i took the opto out of the socket and connected the in and out pins of the the optocoupler the loopback was fine (only i had to connect the remaining MIDI pins with each other otherwise it would not work J12 M- to J13 M- were connected and pins 2 and 6 off the OPTO were connected). When i put the opto in the socket no go (i have +5V between pins 5 and 8 of the opto). I don't know how to check the diode (if it's not broken), i have a digital multimeter with a diode teseter but since i'm a complete n00b in diy electronics i don't know what sould it be showing in both directions of the diode (any help here?).

i'm sorry bad i'm very unsure if im reading the test schematic right i tried drawing what i'm wiring, the led+res on the pic is connected to pins 26 and 31 like i drew, and the pins of the MIDI i/o are shortened like above, the LED lights up but does not turn off when i connect ground to the MIDI IN pin (the other one) is this the right "diagram" for this test ? (sorry for the childish drawings but i'm very "green" when it comes to electronics)

i got a new optocoupler and still no luck what should i be reading on the optocouplers output ? is there some way i can find out if it's passing the MIDI messages what does it do in practice ? i don't know what to do now, maybe i'm looking in the wrong place, and the optocoupler was ok anyway? i'm kinda stuck i'd appritieate some practical advice on how to debug this problem thanks.

yeah that's the only one i didn't do cause i don't have the spare resistors and no vectorboard to attach it, but i'm on my way to the store today to get that stuff and will test it, also i'll get a couple of spare optocouplers anyway. thanks for the help, hope i'll manage to get it working.

just an update: 1) the MIDI event goes on the input (the multimeter beeps on every event) 2) it passes the diode D1 (beeps on both diode ends) 3) the input pin of the optocoupler has the signal (when connected t the optocoupler pin, the meter beeps) 4) when connected to the output of the optocoupler no beeps, the voltage between IC2::5 and IC2::8 is 5V based on this ca i assume that the optocoupler is broken (i've been playing around with the MIDI input polarity alot, trying to figure out witch is right and someone on the forum wrote that wrong polarity can break the optocoupler)

the CORE is not getting anything on it's INPUT, it's sending but not receving (can't upload anything, instead of checksums i get upload requests on every sent data chunk) the debug test1 is this http://www.ucapps.de/mbhp/mbhp_core_midiin_debug.gif the loopback test is with the PIC off the socket and when the TX and RX are connected so everything that comes in should go out (that's not working).

i did the optocoupler test, and 1) after connecting the LED to to pins 26 and 32 of the PIC the diode lights up 2) a connected the MIDI IN and OUT socket pins like on the diagram (led still on) 3) i tried grounding the pin (COM input of my multimeter), the led still on and i checked the optocoupler position, it's ok (opposite to the PIC the dot of the PIC is upper left and the opto is lower right)

I'm getting sme problems with my core 1) The PIC is alive, sends the upload request every 2 sec 2) The LED on the input port flickers on MIDI IN events 3) the MIDI DEBUG test1 - LED is lit but does not flicker on SysEx events sent to the core 4) the loopback test - events are coming IN (checked with a led), but not coming out I noticed with my multimeter, that a MIDI event causes the meter to beep (diode test) on an event i checked the path and up until the optocoupler it's the same beep, but after the optocoupler and on the PIC it's silent, i dunno if this test should pass the MIDI events unaltered, or do they change in some way? i didn't do the standalone optocoupler test cause i don't really understand it any help welocmed, thanks.