Your measurements on red and black are correct. EVGA's charger does not use a center "smart pin", therefore the white wire is not connected to anything to the charger.
Measuring my SC 17, the center pin white wire is being back-fed about 3 volts from the laptop's internal charging circuitry. But since the charger has no connection to that wire, it's inconsequential in my situation. But if your laptop's charging circuitry isn't back-feeding any power-good signal (regardless of whether the charger uses the signal [it doesn't]), I think that indicates that your laptop's internal charging circuitry has a problem.
To be clear, FROM your charger, the white wire will have 0 volts. Like, if you disconnect the header from the motherboard and then measure the voltage on that wire from the charger, there should be no voltage on that pin. That's normal. There is no connection to the charger on that wire. But from your laptop's motherboard, there SHOULD be voltage on the white wire. Like, if you leave the header connected to the motherboard and plug in the charger, you should see voltage backfed to the white wire FROM the motherboard; indicating that the motherboard's charging circuitry is working properly.
I can take pictures of my measurements and measurement methods, if you need something to compare with.
Nothing looks or smells burnt? I think the problem lies on your laptop's motherboard.
post edited by ty_ger07 - 2021/01/20 10:40:24