Canon Battery Pack FN

This is the battery pack that takes 12 AA battery cells.  It has been working since I bought the set in 2010.  Then it stopped working as the battery drained.  I have never used any rechargeable cells with this.

This past weekend I went to IKEA and bought a bunch of rechargeable cells.

Unfortunately they don't work inside this Canon pack.  They mystery is is the pack broken or does it demand the 1.5V per cell very strictly?  The IKEA cell called LADDA is rated at 1.2V at 2450mAh.

I have yet to buy a whole bunch of cells to test it out.  The pack has no response if I set to it OFF, which is expected, but neither is S and L.  The only time the pack is making an effort as if it's trying to wind the film it's when I set it to H.  It makes some grinding noise as if it's trying very hard to advance the film.  I don't believe it's the contacts or something with the camera itself.  It's either the motor is broken, the switch is broken, or some combination of such, or the pack is working but it has no leeway in terms of voltage.  Though that's a bit hard to believe.  I tested the LADDAs in my Nikon F5 and my Sunpak 120J, the batteries have juice to power them.

I know next to nothing to electricity but I read usually the 1.2V would work on 1.5V appliances as when loaded or when over time, the cell can hardly stay at 1.5V.  But the fact that it takes 12 of 1.5V batteries, if replaced by 1.2V then the voltage variance can be quite big when magnified by 12.

I wonder why I don't just go out and buy 12 of those one time use 1.5V AA cell to prove this theory one way or another.

My initial thinking was something wrong with the "motor drive" or even the camera.  But as I did some trouble shooting here and there, I changed my mind.

This battery pack is really just a pack.  It's separate from the actually mechanism that drives the film, which is done by the AE MOTOR DRIVE FN.  The AE MD FN itself doesn't have any power source and it's a separate piece of equipment.