Roland M200 patch issue?

[Hansentd]

Not an audio guy- so this may be super obvious- our space has a Roland M200i- and channels 5 & 6 are not working.

I thought it was the snake- but I tested the lines and they're fine when I cross patch them.
So I looked for a patch issue.

The Channels are patched 1 to 1- with #5 on the snake into Ch5 in the back of the board into Fader 5.
When I switch the patch on Fader 5 to Channel 4 it outputs from Channel 4 just fine- so the output functions but isn't getting an input from the channel.

I also tried copying one of the functional Channels and pasting it onto the non-functional, and then reseting the patch.
That didn't solve the issue either.

What am I missing?

Thanks.

 

[FMEng]

Just to clarify, are you using a snake cable or digital I/O box? Do the sources require phantom power (condenser mic or active DI)? If so, is phantom turned on for channels 5 and 6?

 

[Hansentd]

The snake is an analogue XLR snake.
Something I did find in my test- mapping the non-working channels to otherwise working outputs caused them not to work (and vise-versa)
So it's something within the non-functional channels.

A friend suggested either blow pre-amps in the channels or broken connections in the inputs (they don't feel broken but you never know)
Are either of those something that can be fixed by an end user?

 

[TimMc]

The snake is an analogue XLR snake.
Something I did find in my test- mapping the non-working channels to otherwise working outputs caused them not to work (and vise-versa)
So it's something within the non-functional channels.

A friend suggested either blow pre-amps in the channels or broken connections in the inputs (they don't feel broken but you never know)
Are either of those something that can be fixed by an end user?

To answer the last question first, probably not.

The M200 is very long in the tooth and frankly it's been years since I've seen one in the wild, but I recall that it's possible to disable a channel, and it will not pass audio regardless of the input connected to it. And my memory could be faulty, too.

The Roland was a fairly well thought out system for its time, the REAC i/o racks, etc made it a big jump over the Yamaha 01v96 and similar mixers.

Good luck, and let us know what you find.

 

[FMEng]

Consider whether you can replace the mixer if it dies on the operating table. You might not have anything to lose by trying a repair. Each preamp has a pair of electrolytic capacitors (typically 47 uF or larger, 50-100V) between the connector and the input chip, for DC blocking. Those would be my first suspects. If Roland was smart, the preamp chip might be socketed for an easy replacement, too. Board mounted XLR connectors rarely break, but there's always a chance of a cold solder or crack in a trace. Check for continuity.