MIDI problem

[spoimala]

This is weird enough. When I put a cable from Triton's MIDI OUT to my Scope's MIDI IN, SFP doesn't receive any signal (checked with Midi Monitor).
BUT. When I use a sound module in between (JV-1010 in this case)
TRITON MIDI OUT - MIDI IN JV MIDI THRU - MIDI IN SCOPE
the SFP receives midi signal!

Any ideas?

[astroman]

the midi signal is received as a sequence of pulses that drive an opto-coupler by current (20mA afair).
There is a range of tolerance in which the signal could be too weak (output stage or cable) or the receiving circuit just not sensitive enough.

You probably exchanged the cables already, so if it really turns out that the receiver on the Scope card isn't sensitive enough it's easy to replace.
It's a standard TTL chip which means one can simply cut it off the circuit and solder a replacement on the remaining posts...

Reads more dramatic than it is (and certainly voids warranty), but actually avoids soldering on the (much more sensitive) circuit board, and is almost invisible if done properly.

cheers, Tom

[garyb]

very strange. it's not triton and scope in geneneral that's the problem as i've used tritons many times with scope.

[at0m]

Same here, didn't notice anything abnormal when the Triton was in the chain some years - except for it's fixed 48kHz internal clock eh. Maybe astroman's hint can sort it, or just leave another device in the serial chain...

[astroman]

oops forgot: you should inspect the cable whip for a damaged connection, half-broken wire, 'almost' short-circuit and the like.

if it's ok then loop back through the interface, if it fails insert the 'amp' device.
If it's working then, it's almost certainly the optocoupler.

cheers, Tom