From the SST datasheet:
– 4.5-5.5V for SST29SF020/040
– 2.7-3.6V for SST29VF020/040
Might be a good idea to stick a voltmeter on the power pins (+ve on 8 and Gnd on 24) BEFORE putting the device in the programmer and check you get 3.3V
It's ever so disapointing if you let the magic smoke out

sounds like you are the guy to talk to.
hitachi 47dj = sst39sf020a tsop32 5.0v (badly flashed)
want to replace that chip with one in my lite-on cdrw with mtk controller and sst39VF040 (3.3v) and 4meg plcc
programming would be done with the sst39vf040 in its socket (in the liteon) done with mtkflash or xsf
i would love to put that in my hitachi 47dj, is this possible?
if it is i would also love to have that dual boot bios like you said in another post by making a switch goto a18 and pin9
will this actually work?
thanks