Hello there I was wondering if anyone could help me I have an ASUS laptop charger and I have connected it to the said laptop and teated it with a multi meter and it doesn’t even get up to 19v for one going into the power jack and it also has the voltage going way down to about 0.5 volts and then back up to 8 where it starts. Now I wouldn’t mind having a go at repairing the the charging plug but I wouldn’t know where to start diagnosing faults on the charging plug pcb as I am just starting out in repairing electronics for a hobby, any help anyone could give would be greatly appreciated also I hope I have explained this well enough

 

These are not really worth repairing, they can be very dangerous to work on for a beginner as they are Switchmode types, . Best to just get a replacement one.

 

Too easy to make things worse. That's what I usually do -just buy a replacement.