Have you got a multimeter? Disconnect the amp remote line at the amp end, plug the empeg in. Wait until it's playing music, then put the meter on current and see how much current your amp is pulling through the remote wire.

The amp remote wire is internally fused (resettable solid state fuse) at 1.25A. This line also powers the display (hence why the display is off). If your amp is drawing anything more than about 200mA, I suspect something is funny with your amp - the remote wire usally just switches a relay inside the amp to turn on the main power supply.

Make sure you're not trying to actually *power* the amp off the remote line, this will definitely not work (and would explain the blown 3A fuse, too). The amp should have 3 power connections: ground (to the nearest bit of metalwork in the car), +12v (via a thick bit of wire direct to the battery, with a fuse as near the battery as possible), and REM/remote/control, generally a smaller terminal, which goes to the blue wire on the empeg harness.

Hugo