Any info on laptop power supply brick?

[nomadh]

I have a laptop I'm resurrecting. Took it down to nothing to get to the power jack and got it fixed only to find out that the power brick is dead. Possibly from a fall as it was partially cracked open. Its a 90v 4.74a unit. I was looking at replacing with a 6amp unit to give me some headroom. That should be fine as long as its regulated, correct? I'm finding them for $40 on up but I was interested in actually fixing this unit if possible. Been doing some reading at Sams and such but my theory is really rusty. Haven't had a oscope in 15 yrs but I'd be willing to dig into this a bit and spend a few bucks on parts if I could get some guidance/advice. Anyone have info on doing this before or ideas on how I should proceed? I suspect these psu are getting pretty standard to the point where we could generate a FAQ for this.
Thanks for any help/advice
Damon

[jonnyGURU]

90V? Hot damn! They're usually 19V!

The amperage shouldn't matter as long as it meets the minimum. Like a PC power supply, it's power on demand. The unit isn't alway going to put out 6A.

[nomadh]

Hope that gave you a laugh. Yes its 19v. actually if it was still 19v I wouldn't have a prob but it currently has a declining voltage starting at around 5v and ramping down to <1v. Any guesses where to start troubleshooting?