How about the rest of the boards?
http://www.vintage-computer.com/vcforum/showthread.php?30062-storage-
auction-help!!!&p=218808#post218808
The first one is a mystery--DIO board of some sort?
The second one we know (Sun memory)
The third one looks like a fiber optic transceiver board
The fourth one I guessed as part of a tape drive, but that's just a
hunch, owing to what seems to be 9 analog channels.
The fifth, the homebrew one with 4 RTL PDIPS, a bunch of TO-220s and
some resistors I figured out as a 2-decade BCD counter/decoder. What
for, I have no clue.
I like games like this,
--Chuck