Dead Powerbook 170

I got an Apple Powerbook 170 (68030) from ebay a week ago and today I got a power brick to test it out. The seller said it was dead when he tried to power it (with what power brick and voltage I don't know). I tried it with a 7.5V 2A Sony power brick with the correct end and got nothing (tried it with the main battery removed). Took the unit apart and checked the main fuse and it is ok. The only thing I can see damaged are two power mosfets on the bottom of the board that melted into the bottom plastics (solder on the parts is discolored and one of the legs to ground reads 148 Ohms resistance on both units). The parts are both IRFR9020 (labeled as Q41 and Q43 on the motherboard) https://picasaweb.google.com/107784270771159898725/Broken#55896559704001329… <== shows location http://pdf1.alldatasheet.com/datasheet-pdf/view/115896/IRF/IRFR9020.html <== data sheet Nothing else seems physically blown so I wonder if just swapping those parts out will fix it? Since I don't see the exact International Rectifier part number on ebay what else can I substitute for it? For example we have this part on ebay: http://cgi.ebay.com/Lot-3-P-Channel-Power-MOSFET-15A-60V-0-15Ohm-SMT-SMD-/1… but I don't know how important the Rds Ohm factor is. I have read that Apple original power brick had issues that would blow the surface mount fuse, but no idea what might have caused these chips to overheat so much (over voltage??). Any old Mac laptop people on this list know? Thanks TZ