Some Video:
At first, various types of garbage on screen, and no audio, shown in the video below:

When getting a scrambled screen, or garbage on the screen, it is suggested to remove the rom at location H on the motherboard (or remove all of the roms, it will have the same effect) and see if you get several alternating straight lines, in the video below, it does have this.

This is one of the extra boardsets I have...I'm thinking I may have some RAM issues with this one...note the line pattern that should be there, but the way the screen shifts... I'll have to install the multikit to this board and see what it says.

After installing the Braze Multi-kit, Eureka! I have a picture (but no audio...yet)

Per a suggestion on BrentRadio's Space Invaders Page, I replaced the IN4004 diode right below the Power connector. After replacing the IN4004 Diode, I now have audio. There's a bit of hum noise still, and one of the wires coming off the PS seems to have a bit of a short in it, but it's pretty much fixed now.

(sorry for the shaky image, it's kind of hard to play SI and film at the same time)

Useful Links for Space Invaders:
BrentRadio's Space Invaders Page
ElektronForge- helpful info on testing, plus they Repair and sell Space Invaders boards
Space Invaders Board Pinout (from Robotron2084's page
Marvin3m page on SeaWolf (similar boardset to SI)
DJGallagher's Space Invaders Page
OuterWorld Arcade
Braze Technologies Space Invaders Multi-Game Kit
TNT Amusements- Todd Tuckey
KLOV Forums
Or, if you have any questions, you can shoot me an Email or send me a PM on the KLOV forums