Sundown Audio SIA-3500D Output Mosfets

Can you measure drain voltage? Exact part is impossible, but knowing voltage and current a bunch of possible substitutes we can give.
Thanks for your reply,

Using the PEAK DCA75 I pulled one that I think is good based on its not shorted like 3 others in the row of 8. Here are the measurements from that test.
All 8 are marked H9 so are all 8 N-Channel mosfets?
N-Ch Enhancement mode MOSFET
Red-S Green-D Blue-G
Vgs(on)=4.116V at Id=5.05mA and Ig=0µA
Vgs(off)=3.166V at Id=4.9µA
gm=28.7mA/V at Id=3.0mA to 5.0mA
Rds(on)<1.0Ω at Id=5.0mA and Vgs=8.0V
with body diode