I picked up a Magnavox Micromatic console for my girlfriend for Valentine's Day, and have been trying to get it back up to snuff. It is in great condition, and all works perfect---except the record player! So that isn't leaving much. But the radio, and tape input, etc. all sound great. When I play a record? Very, very weak. It almost sounds like the amp isn't kicking in or something? I have to turn the loudness to max to hear anything. My brother is convinced it is the amp, but I want to be 100% certain before I buy a new pre-amp to put inside. One thing that has me curious is the wiring. This thing looks like someone has tinkered with it at some point, and I'm curious if:
(1) The wiring is even right
(2) The cartridge is or isn't junk
I can find a ton of wiring diagrams AFTER the turntable, but I can't find any that shows how the actual wiring is on the turntable itself. For instance, I can't figure out which of these wires (white, brown, blue-grayish) are ground, right speaker, left speaker. This is a picture of the underside of the turntable. Sorry for flash...it took some color out.

I'm going nuts tinkering, trying to figure out what possible piece needs replacing. Or if the whole thing needs junked.