So I'm sad to report that my RAM replacement didn't go as I had hoped and I think my logic board is toast.
Although I was careful in extracting the old RAM chips, I inadvertently lifted a couple of traces off the logic board. I became aware of the issue when, instead of being greeted by the '? diskette' icon and the normal power-up chime, I was greeted with a black screen and two faint clicks from the speaker. I pulled the logic board to inspect my work, ensuring that I didn't have any cold solder joints or areas where I may have inadvertently created a solder bridge - everything looked good. I then started to check with my meter and as I went through the continuity checks, I noticed that I didn't have consistent continuity across the address pins, I then realized I had broken traces.
After a little digging, I came across this schematic http://www.kiramek.com/21test95/EarlyMacSchematics.pdf, using it to check continuity across all 256 pins, I discovered that I had a total of 4 pins which needed to have traces repaired. I used some wire-wrap wire and made the repairs, but I'm still having the same issue - black screen with a couple of clicks from the speaker.
Since I used dip sockets instead of soldering the new RAM directly, I decided to pull the new RAM and try it with my old RAM - I figured I would at least get back to the point where I had a healthy power-up chime and the display would be corrupted with the 'Sad Mac' error. Instead, I get the same exact thing - black screen, two speaker clicks.
In addition to the lifted traces, I must have some damage in the middle two layers of the logic board. I haven't used the schematic above to test continuity outside of the area of the 16 RAM chips, but I guess that's my next step.
I'll dig deeper tomorrow...
Although I was careful in extracting the old RAM chips, I inadvertently lifted a couple of traces off the logic board. I became aware of the issue when, instead of being greeted by the '? diskette' icon and the normal power-up chime, I was greeted with a black screen and two faint clicks from the speaker. I pulled the logic board to inspect my work, ensuring that I didn't have any cold solder joints or areas where I may have inadvertently created a solder bridge - everything looked good. I then started to check with my meter and as I went through the continuity checks, I noticed that I didn't have consistent continuity across the address pins, I then realized I had broken traces.
After a little digging, I came across this schematic http://www.kiramek.com/21test95/EarlyMacSchematics.pdf, using it to check continuity across all 256 pins, I discovered that I had a total of 4 pins which needed to have traces repaired. I used some wire-wrap wire and made the repairs, but I'm still having the same issue - black screen with a couple of clicks from the speaker.
Since I used dip sockets instead of soldering the new RAM directly, I decided to pull the new RAM and try it with my old RAM - I figured I would at least get back to the point where I had a healthy power-up chime and the display would be corrupted with the 'Sad Mac' error. Instead, I get the same exact thing - black screen, two speaker clicks.
In addition to the lifted traces, I must have some damage in the middle two layers of the logic board. I haven't used the schematic above to test continuity outside of the area of the 16 RAM chips, but I guess that's my next step.
I'll dig deeper tomorrow...