gm5x5x5 problems

[bosone]

i have built the gm5x5x5 some months ago: i remember i tested it and it worked.

now i have rebuilt my studio and i finally connected the gm5x5x5 to the PC.

the problem is that it seems that the out ports 1 and 4 dont work. all the input ports are working and the 2,3,5 out ports are ok.

to test this is used th esame midi cable, connected to an external synth. the midi out signals are sent only if the cable is connected to out ports 2,3,5.

also, the LEDs do not seem to behave in a "normal" way.

i checked the connections and they seem ok (but there MUST be something wrong!!). i also tried to exchange the IC 74HC14 but without success

i'm using the bulk order pcb board, so everything should be straightforward... :(

do you have any ideas??

Edited November 9, 2009 by bosone

[ssp]

bosone, on the board IC2 is orientated with the notch of the ic pointing left on the silkscreen, however pin one is to the right upper. make sure you have this ic in the right way around. also this should be in troubleshooting not mb hui section

Edited November 9, 2009 by ssp

[nILS]

That does in fact seem rather odd. Just follow the path of the two MIDI outs from the gm5 to the sockets and check that all the parts in the path are correct and the soldering is good (pay special attention to the gm5 pins, maybe those two aren't soldered rigtht):

MIDI Out 1:

GM5:14 -> R32 (220) -> IC3:13

IC3:12 -> IC3:11

IC3:10 -> MIDIOut1:5

MIDIOut1:4 -> R31 (220) -> +5V

MIDI Out 4:

GM5:17 -> R12 (220) -> IC6:13

IC6:12 -> IC6:11

IC6:10 -> MIDIOut4:5

MIDIOut4:4 -> R11 (220) -> +5V

Check continuity between each connection and make sure the resistors are 220 Ohm.

[bosone]

bosone, on the board IC2 is orientated with the notch of the ic pointing left on the silkscreen, however pin one is to the right upper. make sure you have this ic in the right way around. also this should be in troubleshooting not mb hui section

actually IC2 (eeprom ,rigth?) is not connected.

[bosone]

solved!

actually, it was just a bad solder (maybe more than one...). it's strange because, as i said, i'm pretty sure some months ago it worked and, with the tester, the connections seemed OK.

i just renewed the solder of out 1 and 4

thanks!

[nILS]

*While* you push down the multimeter probe on a bad solder joint it may well make a connection, especially SMD pins ;)

Glad you got it to work! :frantics: