Soundtracs Console overhaul - tips on workflow?

[mingus2112]

Hey guys,

I've got a soundtracs board (24 channel MRX) that I will start overhauling very soon.  I have to keep the chassis in my garage (where i'm building the studio), where it will remain for several months.  The strips will all come in to my basement shop for testing/overhaul.  Has anyone done this type of overhaul/testing before where the chassis will not be "in the mix?"

Each strip has ports for the ribbon cables to plug into, so I was thinking of building some sort of box that will have the power needed as well as I/O for all of the outputs, bus outs, etc.  Anyone do anything like this before?  I just want to go through each one of these channels one by one (as well as store them INSIDE the house instead of the garage) before the mixer is up.  It'll give me a chance to go through each channel and become familiar with everything about the mixer.  Then, once the mixer is in service, I can have an easy way to bring the channel inside to test and repair if needed.

I've got a power supply from an FMX that I could use to as power.  It'd be nice to put it in a 2U rackmount case (the power supplu is a 2U as well) and then mount the whole thing in a 4U portable box.

EDIT:  I'd also add that any other tips for workflow to test strips individually, etc. are welcomed!

-James

 

[JohnRoberts]

At a minimum you need to be able to accurately measure frequency response. If you can measure THD and S/N all the better.

Perform any mod/rework one channel at a time, but first benchmark all the channels. Look for outlier channels, strips with high distortion, bad frequency response or whatever.

Start by fixing the broken stuff...

Consider making an extender cable so you can plug the strip into the console and test it more or less in place.

If you identify a bad capacitor in one channel you might want to replace all the similar caps in other strips.

Be prepared to invest a bunch of time in these measurements, when the consoles were first built it took hours to confirm they were working correctly.

JR

 

[mingus2112]

Thanks, John.  Definitely ready to spend plenty of time with it.  What will be hard, at least at first, is testing anything in place.  As I said before, I don't have physical room for the console in my shop, so i'll have to start channel by channel.  That's why I was looking for a solution that would work on my bench.  If I have to fix the broken stuff (pots, etc) now in the shop, and then testing fully reassembled a year from now when the garage is finished, so be it.  (right now the garage is not climate controlled - which is why I don't want to store anything but the chassis.  should be OK in the winter, wrapped in plastic and moving blankets with silica gel bags and up off the floor.)

-J

 

[JohnRoberts]

Yes you can do preliminary screening and troubleshooting with a bench test fixture. Mainly you need to provide the correct DC power supplies and can rough test sends to sundry buses with a high impedance scope probe /meter.

You may need to connect multiple different local grounds through the connector as part of the larger console ground design strategy.

The different modules will require different interface connections, but all can be tested independently. 

Of course the bottom line is how they all play together...but you can find many problems in the bench.

A ribbon cable extender requires less thinking.

JR