[sdiy] DX7 battery replacement help

[Jason Proctor]

hi all -- i'm about to dive in and replace the shot battery on my 
original series DX7. i came across some instros here --

http://www.maths.abdn.ac.uk/~bensondj/dx7/battery.txt

-- which specify a maximum 40w soldering iron ("or you WILL fry the board").

i have a Weller WTCPT, which is 60w. i'm fairly handy with a 
soldering iron and the actual soldering looks pretty simple.

question: are some boards so fragile that different wattages would 
mess them up? is it ok to proceed with my regular iron as long as i'm 
super careful?

thanks,
j