Have downloaded a scanned A1200 schematic from
http://www.acc.umu.se/~patrikax/amiga/others/schematics/(A1200R2_0009a.png if you download the A1200r2.zip file)
It looks like U49 is not a transistor as they all have a Qxxx prefix and the circuit symbol is triangular not transistor shaped.
The part reference from the schematic is RHSVA43A if that helps.
