Output monitor volume balance problem

[upstate]

System:

ProTools HD3,version 7.1.8, 2 x 192 I/O, Mac G5 (2X2Ghz) OS10.4.3, Control 24

* Output monitor volume disappears or is significantly reduced on one side (always left).
* Problem is intermittent.
* Usually occurs at beginning of playback but occasionally drops out during play back.
* Volume usually returns to normal after playback runs for a while.
* Sometimes closing and reopening session eliminates problem but not always.
* Problem is probably not speaker or power amp stage related. Occurs on both powered monitors and power amp driven passive monitors.
* Problem occurs with both main monitor and alternate monitor output of control 24.
* Reloading ProTools software did not help.
* I only use stereo mix option in sessions.
* All meter levels(software, control 24 and 192 hardware) indicate balance volume output even when left side volume is lost or reduced.
* There is no " pan" automation written in any sessions where this occurs. Occurs even when everything is panned center.

I am guessing that the problem might be in the control 24 output monitor section but not sure.

Has anyone experienced this problem or know what might be causing it ?

I really don't want to ship the control 24 out for repair not knowing if the problem is even in the control 24 hardware.

Thank you.

[albee1952]

Test by bypassing the monitor section(route your outputs directly to the monitors, use a master track and pull the fader down low to start). If this bypasses the problem, then you could add a simple monitor controller, bypassing the Control24. Options range from this:
http://shop.emotiva.com/collections/.../control-freak
to Presonus Central Station(what I use) on up to the Dangerous 2bus and beyond. The Emotive gadget could sit right on the desk

[upstate]

Dave,

Thank you very much for this suggestion. I will try it. I have looked at some of the "Dangerous" options you suggested. You also suggested some others I wasn't aware of. I'll check them out. Thanks again.