I have a Macbook (mid 2007) that I bought used. I've bought other used Macs without issue, but this was not one of them. I believe it had a liquid spill. I've had to replace the hard drive and keyboard/upper case. I bought the MagSafe DC-In part because #1 -the battery won't charge past 72% (it only has 65 cycles on it), and #2 - the MagSafe adapter will flash between green and orange with the "not charging" message in the menu bar. From what I had read, I was hopeful this part would solve the problems with charging. It did not. I am still experiencing both problems. I've tried other "fixes" for this issue as well. Totally discharging the battery, resetting the PRAM, resetting the SMC, etc. None of these helped either. I believe my only other options now are replacing the motherboard (which I will not do) or purchasing another MagSafe adapter.
My son installed the part. Aside from having to deal with the teeny tiny screws and the trickiness of reinstalling the keyboard/upper case. It went fine.
I don't have any meaningful advice to give regarding this repair since it didn't fix my issue. If someone else needs to install this part, I would say that it is something can be done with relative ease by someone familiar with computer repairs.