MIDI fader Jumps in Scope mixer when I use external control

[Music Manic]

Hi Guys,

I have re-attached my behringer BCF 2000 to control my Scope Mixers.
I find that when I move the external faders it transmits odd values and makes the scope faders jump until they land in the right place.

I remember it working. Could it be the MIDI cable?

Any ideas?

[siriusbliss]

MIDI loop?

G

[dante]

You could put a MIDI monitor in the Scope project to see what BCF is transmitting. Maybe your BCF is in a different mode or something. Then you could try a different cable as well see if it makes a diff in the monitor.

[Music Manic]

Hey guys I've just tried the Midi of my 3rd card and it works smoothly.

It's definitely the 2nd card's Midi. I'm worried It's faulty now. I need all the Midi to work.

I will try and unplug and replug it.

[astroman]

you could setup a local loop on the card, feeding the physical midi out with a software CC
plug the cable into the midi input (where the BCF was) and connect a midi monitor to the midi source module
for more precision you could generate the increasing/decreasing CC via LFO
if the monitor reveals jumps in value, it's probably the midi receiving optocoupler gone bad

to check the sending port you'd need another card (or system) to monitor the output in a similiar way.
the optocouplers are the 2 8-pin ICs (relatively large, non-smd parts) on the IO plate

cheers, Tom

[garyb]

bad cable whip? it could be solderin' time...

[astroman]

oops, forgot about that (most obvious) - sure the whip should be checked before anything else...

cheers, Tom

[Music Manic]

I tried the MIDI cable in another card and it's ok so it's definitely from the card.

What do I need to solder or can I buy I new plate? It's a PULSAR 2.

Bought it second hand and it looked like it had been tampered.

Is there a way of checking anything else?

I believe this card causes the scope system not to be seen sometimes.

Thanks

[garyb]

well, first i'd inspect the connectors on each end of the cable whip. you'll need to disassemble. a meter might help as well...

it could be the plate, but i doubt it.

[Music Manic]

well, first i'd inspect the connectors on each end of the cable whip. you'll need to disassemble. a meter might help as well...

it could be the plate, but i doubt it.

Hi Gary,

I took the cable set out of the card with the problem and attached it to the anther card. The result was smooth and all worked fine.

I'm going to give it a more intensive test when I have time today and will report any findings.

The thing is all seems ok when it comes to audio etc for the same cable whip that has the problem.

It is a repetitive problem that is quite consistent. The MIDI monitor shows jumps, of the fader, to about 07 ever time I move the fader up and down. Outputting the midi to the berhinger seems ok.

I wonder if there is a software problem.

Thanks all for helping

[astroman]

in that case it's rather the afforementioned optocouplers, the receiving one at least.
Do you have another one to exchange the IO plate ?
Imho it's very unlikely that only the midi part (of the software) fails.
Btw the cable whip is famous for short-circuiting the S/PDIF connector(s) which results in loss of sync causing weird side effects.

cheers, Tom

[garyb]

astro is probably right on the money, i'm afraid.
the chance of a software issue is very near none.

[dawman]

See if it's a system reset message.
I use hardware MIDI and filter everything.
Also use 4 x Stock Scope MIDI FIlters on each Source and Dest module.
One way to confirm this is use the MIDI Monitor and see if anything close to this message appears.

11111111= FF= 255 or Reset.
Roy's LCD Monitor is much easier to read than the muchkin scribblings in Scope's Monitor.

[Music Manic]

Yep Astroman I think you are right with the optocouplers.

Everything else seems ok so I guess I can get by without the MIDI.


Is there a circuit diagram which will show me which part I need to replace if needed?


Thanks for all your help

[astroman]

no need for a diagram: if you look at the IO-plate it's the 2 8-pin 'regular-size' ICs at the (innermost) corners of the circuit board. On mine they are labeled QTC 2601, HP 2601 may have been used as well.
If you're not familiar with desoldering such parts, just cut them out and solder the new ones on top of the pins left in.
You may shorten the pins of the new ones for their 'slim' parts. There's enough space there.
Doesn't look cosmetically smart, but is better than spoiling the IO-plate, which is quite delicate.

cheers, Tom

[Music Manic]

no need for a diagram: if you look at the IO-plate it's the 2 8-pin 'regular-size' ICs at the (innermost) corners of the circuit board. On mine they are labeled QTC 2601, HP 2601 may have been used as well.
If you're not familiar with desoldering such parts, just cut them out and solder the new ones on top of the pins left in.
You may shorten the pins of the new ones for their 'slim' parts. There's enough space there.
Doesn't look cosmetically smart, but is better than spoiling the IO-plate, which is quite delicate.

cheers, Tom

Thanks Astroman.

Really hard to find those parts now in the UK. Googled everywhere.

[astroman]

this is strange... it's a very, very common IC.
Any electronics DIY shop should have them (or similiar types) on the shelf, at least the HP2601 (only the label is different). I'm almost certain I have some on old soundcards supposed to go to the trashbin...

cheers, Tom
(sorry different part - but Reichelt sells them for 1 Euro/piece)

[Neutron]

according to this

http://www.fairchildsemi.com/ds/6N/6N137.pdf

the 2601 is the same thing as the much more common 6N137

[Music Manic]

Hey Astroman and all, I believe that the whole card is faulty now.
I get the occasional "card 2 has lost contact" error and the card may be causing
side effects like you said.

Is there anyone that repairs them at all?

Thanks

[garyb]

maybe. maybe it's time to clean the connectors...