Howdy,
I got my 2002 F150 back in June of 2005, and replaced the factory audio system within a few days with some stuff I had in a Mustang previously.

Here's a run down on what I have:
Alpine HU (kinda old, only single CD)
Phoenix Gold XS 6600 Amplifier (6 channel)
Infinity Reference 1050 10" 250W Subwoofer
Polk Audio 2-way 60W 5"x7" in front
Blaupunkt 3-way 60W 5"x7" in rear

Anyway, I've noticed a few problems with the audio system lately. First, I'm pretty sure my driver side front speaker is blown out because it sounds like crap half the time, and doesn't have any output the other half. Also, it seems like the entire front speakers cut out occasionally.

The first few times this happened, I thought the speaker wires had become disconnected from the speakers. I pulled off the door panels and checked them, but over time this has not solved the problem. I checked the speaker wires for all four speakers at the amp, as well as the power, ground, and RCAs (both front and rear channels), and everything is connected properly.

The only reason I can think of why my signal is cutting out on the front channels is that maybe the RCAs on the back of the head unit have come loose.

Being that my system is pretty simple, does anyone think I'm on the right track? The sub in my dad's truck was behaving like my front speakers, and I discovered that the RCAs on his HU had actually broken off. This leads me to believe that I may have a similar problem (only just loose, not completely broken off!).

My next question is, how the hell can I get the HU out to check? I borrowed some of those U-shaped prongs from a neighbor to get the factory radio out, and install the Alpine HU. Can I improvise, or where can I but the tools?