so i am engineering an internet / VT studio for a client. he has a arrakis 12k series console. i wired up punch blocks to the inputs, triple checked my wiring against the manual. so i hooked up a mic through a dbx 286 both confirmed working even tried different wiring between mic and dbx and punch block. i can't seem to confirm via meter movement that board is passing audio. i did add a line to mic level pad so i don't blow the mic channel inputs and i did jumper the prefader i/o on cn3 terminal. also the board has some mods pictured here
Dropbox File (Private or Invalid)
i am unfamiliar with these mods although i have seen such mods in many studios i have no personal experience with these types of mods.
my question is does anyone have a experience with these boards that can shed some light on why the board does not appear to be passing audio?maybe i'm missing something simple? also can someone shed some light on these mods maybe via engineering notes of similar mods?
a lot of engineers have had there fingers in this particular pie and to top that off the guy when he moved did so in a hurry and just cut and ripped wires so i am basically deciphering several other engineers work with no notes on anything except the first engineers install nothing on the subsequent modifications to the original install and rebuilding the studio from scratch.
any help on this would be greatly appreciated i am studying the manual in the mean time to see if i am missing something that is preventing board from passing audio.
Not sure the vintage of this particular console, but on many of them, Arrakis used to use VCA chips instead of faders and a summing op amp to control audio. The part has been out of production for a long time and a direct-swap replacement isnt being made; which means if a VCA went south on you, you'd need to create a little "crossover socket" to make a modern one work.
Do you have a signal tracer -- i.e., www.grainger.com/product/52ZK79 ? Huge timesaver if you have to go stage-by-stage.
Is signal moving thru on other inputs, like the CDs or the three automation inputs? How about on any of the three busses - Prog, Aud & Utility? If they also are not passing audio, suspect a problem with the motherboard or one leg of the power supply. Look for a telltale coffee spill inside the chassis.
If I had to guess about the mods, the switches look like a poor man's mix-minus, where callers can hear a signal from the microphones; and as the pushbuttons are all harnessed together, they look like controllers for the automation (STOP, START, NEXT, MANUAL/AUTO). No idea what that Blue/Red thing is all about.
Let us know what you find out.
here is some more info on the problems with the arrakis,,,
i got audio going through it but now audio passes regardless of state of unit whether is has power or not and regardless of state of pots and channel on/off switch.
link to more info,,,
http://www.broadcastengineering.info/viewtopic.php?f=39&t=6174
problem solved chassis needed an electrical or earth ground. i grounded chassis to an electrical outlet screw and all the issues went away and board started to function as normal.