Mac LC II Memory Issue

So I've recently installed 2 4MB SIMMs in my LC (which has System 7.5.3), and when I go to power on the computer, it gets stuck at the welcome to macintosh screen. I've tried to disable extensions but that didn't work, but when I tried to boot off of a 6.0.8 Disk Tools floppy it booted all the way and I was able to see I had 10 MB installed. So then I made 7.0.1 Disk Tools floppy thinking it was my hard disk installation having a problem but that also gets stuck on the welcome to macintosh screen, and when I remove the new RAM it boots fine. Anyone have any idea why this is happening?

 

The thing is that I've copied the system folder from the boot disk to the hard drive and it worked so I've pretty much ruled out hardware problems.

 

Right now I can't take any pictures of the ram but I can tell you that they're 30 pin parity SIMMs, one that's 80 ns and the other is 70 ns, and they both have 9 separate chips on them.

EDIT:
Added a picture of the RAM, It's a bit bad quality but I think you can see them pretty ok. The chips read M5M44100J 121SG7C-8, and they have the Mitsubishi logo on them.

 

Ok, so I've looked into the capacitors and I think all of them are fine. I can't test them with a voltmeter now but none of them are leaking and I don't see any corrosion on the logic board. But I have to ask, what changed between System 6 and System 7, because the earlier one works while the newer one gets stuck on the start-up screen?