schematic diagram for eclipse 3242 amp?

Hello, I have this nice amp by Eclipse, but it is starting to show it's age with some nonsense problems. First, the rear channels only work in full range, not hi-pass or low-pass. The switch is ok, but there must be something wrong within the crossover circuitry here. The next issue is that the front channel LEFT side cuts out, but it will tun back on when the volume is turned to MAX range. It's a newer model JVC head unit, probably not more than 2v output, for some reason it needs to be over a certain threshold for the signal to pass through. The RIGHT channel works fine, the LEFT even sounds perfectly fine when it works, it either works or it doesn't. I've checked all of the switches with my multimeter and those are all fine. I haven't followed the signal yet since my scope is also down... Where can I get a schematic for this Eclipse 3242 4 channel amplifier? It is this one here: http://ampguts.realmofexcursion.com/Eclipse_3242/ I've looked it over and can't seem to find anything that could cause this like bad solder joints.

Thanks idiot, That information is very useful. I was originally thinking I may have to simply bypass the pre-amp stages, but I'd rather this be fully functional as long as there is hope. I just need to figure out how to power it on inside, I have a 12v jumper pack, but I'm not sure how long that can sustain. I read somewhere that 36 amps is the recommended minimum for testing amplifiers. I could play with it in the truck, I just don't want the neighborhood kids to know about my gear.

You can easily power the amp with the jump pack.  At idle it will pull less than 1 amp.  Playing a single speaker at a volume loud enough to hear it will require only 2 or 3 amps of current. Let's Go Brandon Brown. Congratulations on your first Xfinity Series Win. LGBFJB

Thanks, I looked at those pins and the soldering looks fine, the next step is hooking up the battery pack and getting some voltage readings on those pins.