Mic issue

I borrowed a condensor mic from a studio, to record some stuff and I couldn't seem to get it going. Weird.

It was an MXL, large diaprahgm. I was using a Mobile-Pre unit, which was recording guitar just fine, but then I went to put the mic into the XLR input for channel 1 and had taken out the guitar input line.

Here's what happened--I could actually hear sound through the speakers coming from the mic, yet no signal! Nada. Weird. How can you get sound come in through your pc speakers and not have any registered signal.

Not only that, but I couldn't record anything or didn't know what was up at least..

Then the silly program froze up on me and I couldn't save anything or maybe it was not in the right file format? I don't know. I saved something today, so maybe it was a glitch.

What to do on the mic?

Yes, the phantom power was turned on.

I think one time it looked like signal was trying to come in and I saw it register and then the other time--no signal.

I had the audio engine button running--next to the reset button at top in the play toolbar. I usually hit that to get the signal going for each track, which took some time or fiddling to figure out...

Yesterday I tried using the mic on my Tascam 424 MKII Portastudio and couldn't get any signal coming in either. So maybe it is the mic?? Tried using the batter power on the Portastudio. Nothing.

I am going to try one more time today. If it doesn't work, well back to the studio... I wonder if they let me borrow a messed up mic?