If you look on the under side of the 1200 there is a trap door open this and thats where the extra memory board will be if its got an upgrade.
I used to have a 500 and a 600 and a 1200 and a 4000 Amiga i also used to stand accy market selling Amiga stuff.
i changed my 1200 and put it into a tower so i could add extra stuff like cd player and writer.
Funnily enough i got a text the other day from someone in Blackpool who is after a Amiga 1200 so if you cant sell it let me know
