I'm having power issues with my laptop, a hp zd8000. The powah brick mains adaptor thing kinda blew-up, well shorted out, as the case was loose and some of the wires would shift around when I pushed it back together (stll plugged-in to the mains, as you do).

Anyway I have a replacement but with the adaptor plugged in the battery symbol is always flicking on/off ie, one for a couple of seconds then back off again. Looking into power manager it's constantly switching betwen mains ac adaptor and battery power

It eventually runs the batterydown and shuts off but the battery will charge if left plugged in and shut-down for a couple of hous. I also noticed the adaptor is a slightly lower rating @

input 100-240v 2.2a output 19v ~ 7.1a

against the original

input 100-240v 2.9a output 19v ~ 9.5a

So I guess the adaptor isn't man enough to run the laptop and charge the battery ? The battery iteslf is maybe 2 months old. The pc is a hand-me-down so there's no warranty or anything.
Soz if t isn't obvious but I haven't payed attention topc hardware for years.

That 2 amp output difference is more than enough to cause this problem, clearly it is underpowered (2 amps is a big difference). You should be able to find power adapters independently, either at a computer store of some sort or the internet. Next time make sure to check the power ratings, to be sure that they match.