30 Mar
2011
30 Mar
'11
11:21 a.m.
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#558965597040013=
2978 <=3D=3D shows location=20
http://pdf1.alldatasheet.com/datasheet-pdf/view/115896/IRF/IRFR9020.html =
<=3D=3D 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:=20
I never think of E-bay as a source of components. I am quite sure that
most E-bay sellers are honest, but since components are something I can't
repair and are thus worthless if faulty, I prefer to deal with a
well-known company.
In this case, it appears that the origianl part is easily available.
I looked at Farnell and Digikey, both sell it. I am sure plenty of other
places do too. In this case, I'd fit the original part.
Whether that will cure your problems, I don't know. I have never seen
inside such a machine so I have no idea as to the circuitry and what ele
might have failed.
-tony