I have an Alpine MRV-F540 - At moderate to high volumes it goes into
protection mode. It just started recently and is getting worse. It also only
happens when I am driving all 4 channels, or if I bridge down to 2 channels.
IOW, if I fade all the way to front, it won't go to protection, if I fade
all the way to the rear, it won't go into protection - only when i'm pushing
the amp semi-hard, with all channels driven does it go into protection.

I checked *ALL* connections - and re-connected all leads at all terminals
(amp terminals, distribution blocks, chassis ground, battery fuse, etc.)
just to be safe. Turned everything back on and damn if it doesn't keep doing
it.

Got out the Fluke DMM to see how bad a voltage drop I have at the amp
terminals when playing at volume. With car off, low volume 12.1v, when it
cuts off at high volume - 11.8v. With the car running low volume is 14.4v,
and at high volume when it cut off the volume was 14.1v.

These voltages were measured at the amplifier terminals - it tells me that I
don't have a loose connection somewhere - and it's not a battery supply
voltage problem because the terminal voltage never falls below an acceptable
level.

I checked speakers, and even attached different pairs with the same result.
nominal dc resistance is 3.6 ohms on each front speaker and 3.7 ohms on each
rear speaker. No shorts here either.

The amp was purchased new at the end of December, 2003 and is still under
warranty.

Can anyone think of something that I'm missing or is it time to send it back
to Alpine for repair?