Our antique g4 iBook would no longer charge, and no power was getting to the unit. We could charge the battery externally and run the laptop on that so we knew it had to do with either the power supply or the circuit board. After testing with a known good power supply, that narrowed it down to the DC In board.
Researched on-line for a DC-in bard and ordered one from an outlet in Hong Kong, that never came (hylove.com, don't order there). Then discovered iFixit, and took another gamble. Received the part very quickly. Was advertised as used, but the part looked to be new in a sealed bag. Price was excellent.
The repair of the DC in-board is very easy, you just have to be very careful not to lose any of the small screws when taking the iBook case apart. Also, separating the case was initially a little tricky, especially the two snap points to the left and right of the screen hinge. It took me more time to unsnap the case than any other part; probably 1/2 hour total (being very careful, and not wanting to break any small plastic tabs).
Once the case is opened and the shield is off, very carefully remove the old DC-Inboard. It is take the held securely to the motherboard by sticky tape.
The iFixit guide is good. Watch that you don't break the tab in step 9.
Be gentle in separating the case, and use a small flat head screw driver. The plastic will scratch if the screw driver slips. Three of the screws are under the rubber feet. I did not use spudger or a tool, the metal rings around the screws stayed with the screws. After the case was unscrewed, I left the screws in place in the case. This is step 5 in the iFixit guide.
There are two springs that sit under the edge of the battery, covered with two small plastic inserts. Don't lose them.
The screws were a mix of small Phillips (00?) and T8 Torx. If you don't have a T8 Torx, a very small Allen wrench will fit (5/64?), but be very careful in tightening and loosening. If your laptop has security Torx, then you will have to use a security Torx wrench, nothing else will fit.