Monitor display help request

[unclet]

Maybe someone can help me.  I have a Space Encounters arcade cabinet which I am trying to revive.  I have verified the motherboard PCB and daughter board are receiving the appropriate power supply levels.

I have some new 2107 Ram replacement chips which I just received and am trying to locate which Ram chips are bad.  I am trying to do this by setting the DIP switch settings to "RAM test" and then placing one new Ram chip on top of each of the 16 existing non-socketed Ram chips on the motherboard PCB.  I was hoping this would tell me which Ram chip was bad by eventually displaying the nice RAM test display on the monitor, however, this never occurred.

I actually tried every combination of one new RAM chip piggy-backing the exist RAM chip as well as even combo of 2 new RAM Chips piggy-backing two existing RAM chips.  No luck.

The following are pictures of what I am seeing:

1) This shows what I see when the RAM test DIP switch IS NOT on when the cabinet is powered on.

http://unclet.arcadecontrols.com/SpaceEn/myRamTestDipOff1.jpg


2) This is what my monitor fades to every now and again while the RAM test DIP switch IS NOT on.

http://unclet.arcadecontrols.com/SpaceEn/myRamTestDipOff2.jpg


3) This shows what I see when the RAM test DIP switch IS on when the cabinet is powered on.

http://unclet.arcadecontrols.com/SpaceEn/myRamTestDipOn.jpg


4) This shows what I see when the RAM test DIP switch IS on and one of my new RAM chips is on one of the old non-socketed Ram chips on the PCB.

http://unclet.arcadecontrols.com/SpaceEn/myRamTestDipOnWithNewRam.jpg



Any help with what I should do to resolve the problem as to why I can not see a nice game image would be nice..... 


QUESTIONS:

a) Are my Roms bad (based on the images ... if you can tell)? 

b) Can I simply piggy-back all 16 socketed RAM chips with 16 new 2107 replacement RAM chips all at the same time?

c) Am I damaging my PCB or RAM by piggy-backing RAM chips?

Thanks
UncleT