I can help with determining the size:
The memory chips are GM71C4400, which are each a 4 megabit chip (1M x 4 bit). Each SIMM has 32 chips (16 on each side) so it appears these are 16 megabyte SIMMs.
30-pin SIMMs have to be matched in sets of four in the same bank, so you can't get away with only putting 2 in. You could try cleaning the contacts on the SIMMs, but they might just be bad. If all else fails, OWC sells replacement 16 MB SIMMs.
The memory chips are GM71C4400, which are each a 4 megabit chip (1M x 4 bit). Each SIMM has 32 chips (16 on each side) so it appears these are 16 megabyte SIMMs.
30-pin SIMMs have to be matched in sets of four in the same bank, so you can't get away with only putting 2 in. You could try cleaning the contacts on the SIMMs, but they might just be bad. If all else fails, OWC sells replacement 16 MB SIMMs.