I am the original owner of a 128k Mac from my first year at Drexel University in 1985. I am trying to restore it back to operating condition. When I powered it up I got the Chime and then the Sad Mac Icon with code 040820 was displayed with a good quality screen picture. So I replaced RAM chips G8 and F10. After that I powered it up and got the Chime and then the Sad Mac Icon with code 020040 was displayed, also with a good quality screen picture. So I replaced RAM chip F11. Now when I power it up I no longer get a chime, the screen comes on with basically a white/black static display, and I get random static sounds out of the speaker. See two links to videos of the current symptoms. Any idea what might have gone wrong with my second RAM chip replacement, or other ideas of what could be wrong now?