Cannot change sub in speaker set up

Been a while since I've had reason to say much here and unfortunately now it's to report a perplexing problem. I run 950/770 and all has been fine until just last couple of days.
No sub output through SuperCube; and when I go into speaker set up (to check if sub was still selected) I can change any settings there EXCEPT the Sub setting. In other words can modify all other speakers from small/large/none, but sub is set to ON and will not respond to any commands.

This is obviously odd and I want to set this straight before I move to another trouble-shooting step to figure why no LFE

any ideas??

Have you tried resetting the 950? Could be a way to shake things loose.

OK Ok hold on.... I changed the fronts and the center to large which let me then change the sub...when the fronts and the center are set to small I cannot change the sub setting from ON. Is this standard operating proceedure??

Gonk how do I reset; besides just turning off then on?

Ah, you got it - the fronts must be set to "large" in order to turn off the sub, otherwise there's no place to re-route the LFE. Perfectly normal behavior.

There's a blurb in the manual in resetting, you have to pop the volume knob off and push a button hidden there.

Ok things all SEEM to be set up correctly (remember this has been running fine for some time now)...and I did reset the 950.
but even playing Dr Chesky's SACD which has a whole lot of LFE and listening to the LFE sections alone...there is almost nothing coming through the sub. Enough that it turns on as it recognizes a signal but nothing to speak of (or hear). Have sub volume truned up all the way too and it has never been past a hair beyond 1/2 way.
Can't figure out how to trouble shoot whether it is Supercube or 950 problem

Keep in mind that an SACD is going to not use the digital bass management - I'd look first at the player's settings and second at the position of the bass management switch on the back of the 950. Is the loss of sub signal appearing just on SACD or DVD-Audio discs, or is it across the board? Also, have you tried the 950's test tones to see if there's a problem with the level there (which might indicate a problem with the sub if the setup had been working previously)?

I've got almost nothing coming through using the 950's test tones with the other speakers responding very well. I have calibrated this system numbers of times before and though the sub test tone never jumps out like the others, at least I could hear/feel it. But not now. Maybe I need to take the sub over to my dealer tomorrow and see how it sounds there before I make myself too crazy. That at least involves the smallest amount of un-wiring to see if the problem lies there.
Hope it's not the 950. Funny how LFE just stopped responding. I even swapped the LFE RCA connector and same thing is happening.

I doubt it's the 950, as it's sort of an odd failure. If you want to try something tonight without major re-wiring, you could hook the sub directly to the LFE output of your SACD player and tinker with that a bit to see if the sub's amp or driver is the culprit.

Wanted to update this since I found out today that my 950 is in the clear, hooray for Outlaw.
I dropped by my dealer and we looked over/hooked up the SuperCube on their bench....they got the same nothing I got... after which a call was placed to Chet at Def Tech and new crossovers are being sent. Who knows how it happened (the sub is seperately surge protected)so it's just one of those flukes. Thanks Gonk for the input ..as always you're a responsive and good resource.
My son just asked if everyone on this forum is a geek...I said I guess so when it comes to audio. Meant or not, I took it as a compliment.

Ah, geekdom... Not a bad thing.

Glad to hear you tracked down the problem.