Mjw,
Unlike desktop power supplies the voltage and amperage outputs vary greatly from laptop mfg to mfg, so a unit like the one included with PC-Doctor won’t work. Then there is the connector issue, everyone seems to have a different one.
The easiest way to test it is with a voltmeter. When, in a previous life, I was testing a lot of the same type of laptops I made up a little pigtail with a male and female connector so that I could put the multi-meter in parallel and test for voltage drop under load.
-Fred
