How many SNES variations?

[zedrein]

I've been in the market for an original model SNES that has the APU as a separate unit [in a aluminum chassis] that attaches to the console, so I logically went searching for model # SNS-001, as many knowledgeable people told me to, and eventually I found one at the local Goodwill, but when I got home and opened her up to do the S/PDIF mod I discovered it was the two chip model with the chips attached to the main board! This was confusing as all the information on the interwebs told me to look for the first model version for my purposes. Does anyone have a detailed chart of some sort that can help me differentiate between all of the variations? Thanks.

[kamiboy]

Google is your friend.

[zedrein]

Thank you, friend.